Contact Dermatitis

Complex MONDO:0005480 Pathograph 15 Dermatological Disease Inflammatory Disease

Contact dermatitis is an exogenous inflammatory eczema triggered by direct skin exposure to irritants or sensitizing allergens. The umbrella disorder includes irritant contact dermatitis, driven by barrier injury and innate inflammation, and allergic contact dermatitis, driven by hapten-specific type IV T-cell immunity after sensitization.

3
Mappings
2
Definitions
0
Inheritance
13
Pathophysiology
2
Histopathology
4
Phenotypes
15
Pathograph
2
Genes
4
Treatments
2
Subtypes
3
Differentials
2
Datasets
2
Trials
0
Models
1
Literature
🏷

Classifications

Harrison's Chapter
skin disorder
🔗

Mappings

MONDO
MONDO:0005480 contact dermatitis
skos:exactMatch MONDO
Primary MONDO disease identifier for this contact dermatitis entry.
ICD-10-CM
ICD10CM:L23 Allergic contact dermatitis
skos:closeMatch ICD-10-CM
Contact dermatitis includes allergic contact dermatitis as a major clinical subtype.
ICD10CM:L24 Irritant contact dermatitis
skos:closeMatch ICD-10-CM
Contact dermatitis includes irritant contact dermatitis as a major clinical subtype.
📘

Definitions

2
Clinical syndrome definition for contact dermatitis
Contact dermatitis is an exogenous eczematous inflammatory disorder caused by direct skin contact with an external substance, most commonly expressed as irritant contact dermatitis or allergic contact dermatitis at sites of exposure.
CASE_DEFINITION General clinical framing of contact dermatitis in dermatology and occupational medicine
Show evidence (2 references)
PMID:25102574 SUPPORT Human Clinical
"Contact dermatitis results from skin contact with an exogenous substance."
This supports the core disease definition as dermatitis caused by external cutaneous exposure.
PMID:25102574 SUPPORT Human Clinical
"The two most common variants are irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD)."
This supports the umbrella disease definition encompassing irritant and allergic forms as the principal variants.
Practical diagnostic definition for suspected allergic contact dermatitis
In routine practice, suspected allergic contact dermatitis is defined by a compatible exposure-linked dermatitis pattern evaluated through focused history and physical examination, with patch testing used to confirm relevant sensitization and distinguish allergic from irritant disease.
DIAGNOSTIC_CRITERIA Clinical diagnosis of recurrent, persistent, or exposure-pattern dermatitis suspicious for allergic contact dermatitis
Show evidence (2 references)
PMID:31757238 SUPPORT Human Clinical
"Diagnosis is based on a thorough history, physical examination, and patch testing."
This supports the practical diagnostic framework of history, examination, and patch testing.
PMID:25102574 SUPPORT Human Clinical
"If ACD is suspected the patient should be referred to secondary care for patch testing."
This supports patch testing as the confirmatory step when allergic contact dermatitis is suspected clinically.
◆

Subtypes

2
Allergic Contact Dermatitis
Delayed type IV hypersensitivity dermatitis caused by prior sensitization to a contact allergen.
Show evidence (2 references)
PMID:25102574 SUPPORT Human Clinical
"Classical ACD is mediated by type 4 cell-mediated immunity."
This review explicitly defines allergic contact dermatitis as a type IV cell-mediated immune process.
PMID:19839974 SUPPORT Human Clinical
"Allergic contact dermatitis (ACD), one of the commonest occupational diseases, is a T-cell-mediated skin inflammation caused by repeated skin exposure to contact allergens, i.e. nonprotein chemicals called haptens."
This supports allergic contact dermatitis as a hapten-driven T-cell-mediated subtype of contact dermatitis.
Irritant Contact Dermatitis
Non-sensitization-dependent dermatitis caused by direct toxic or barrier-disrupting effects of an exposure.
Show evidence (2 references)
PMID:25274939 SUPPORT Human Clinical
"Irritant contact dermatitis (ICD) is the most common form of contact dermatitis."
This supports irritant contact dermatitis as a principal subtype within the broader contact dermatitis category.
PMID:25102574 SUPPORT Human Clinical
"ICD is a form of eczema and is induced by direct inflammatory pathways without prior sensitisation."
This supports the non-sensitization-dependent inflammatory mechanism of irritant contact dermatitis.
📚

References

19
PMID:19839974
Effector and regulatory mechanisms in allergic contact dermatitis.
No top-level findings curated for this source.
PMID:25102574
Identifying the causes of contact dermatitis.
No top-level findings curated for this source.
PMID:25274939
Irritant contact dermatitis.
No top-level findings curated for this source.
PMID:31757238
Allergic Contact Dermatitis.
No top-level findings curated for this source.
PMID:38713001
Differential diagnosis of contact dermatitis: A practical-approach review by the EADV Task Force on contact dermatitis.
No top-level findings curated for this source.
PMID:39709083
Epidermal spongiotic Langerhans cell collections, but not eosinophils, are a clue to the diagnosis of allergic contact dermatitis: A series of 170 clinically- and patch test-confirmed cases.
No top-level findings curated for this source.
PMID:26370659
Prevalence of contact allergy in the general population in different European regions.
No top-level findings curated for this source.
PMID:23343419
Filaggrin mutations are strongly associated with contact sensitization in individuals with dermatitis.
No top-level findings curated for this source.
PMID:23039796
Impact of atopic dermatitis and loss-of-function mutations in the filaggrin gene on the development of occupational irritant contact dermatitis.
No top-level findings curated for this source.
PMID:19580930
Management of occupational dermatitis.
No top-level findings curated for this source.
PMID:30465037
Allergic Contact Dermatitis to Mastisol Adhesive Used for Skin Closure in Orthopedic Surgery: A Case Report.
No top-level findings curated for this source.
PMID:41804652
Prevalence of Contact Allergy to Isothiazolinones in Dermatitis Patients From 2000 to 2025: A Systematic Review and Meta-Analysis.
No top-level findings curated for this source.
PMID:41784277
Systematic Review and Meta Analysis of Allergic Contact Dermatitis from 2-Octyl Cyanoacrylate Adhesives.
No top-level findings curated for this source.
PMID:41064302
Mojito-Induced Phytophotodermatitis: A Case of Lime-Triggered Skin Reaction.
No top-level findings curated for this source.
PMID:40921440
Allergic Contact Dermatitis Triggered by a Mare's Milk-Based Soap.
No top-level findings curated for this source.
DOI:10.1073/pnas.2009192117
Machine-learning–driven biomarker discovery for the discrimination between allergic and irritant contact dermatitis
No top-level findings curated for this source.
DOI:10.1155/2013/916497
Cytokines and Chemokines in Irritant Contact Dermatitis
No top-level findings curated for this source.
DOI:10.3389/fmed.2023.1184289
Advancing the understanding of allergic contact dermatitis: from pathophysiology to novel therapeutic approaches
No top-level findings curated for this source.
DOI:10.1111/all.16642
Transcriptomic Analysis of Allergic Patch Test Reactions in Non‐Atopic Patients: A Comparative Study Across Multiple Allergens
No top-level findings curated for this source.
⚙

Pathophysiology

13
Irritant exposure and toxic insult
In irritant contact dermatitis, direct exposure to chemical or physical irritants causes the initiating toxic cutaneous insult.
Show evidence (1 reference)
PMID:25274939 SUPPORT Human Clinical
"It represents the cutaneous response to the toxic/physical effects of a wide variety of environmental agents."
This supports direct toxic or physical exposure as the initiating event in irritant contact dermatitis.
Epidermal barrier disruption
Irritant injury disrupts epidermal barrier integrity and creates the tissue context for downstream inflammatory activation.
keratinocyte link
Show evidence (1 reference)
PMID:25274939 SUPPORT Human Clinical
"involves skin barrier disruption"
This identifies barrier disruption as a distinct mechanistic step in irritant contact dermatitis.
Keratinocyte activation and proinflammatory mediator release
Barrier-injured keratinocytes enter an activated inflammatory state and release mediators that propagate local cutaneous inflammation.
keratinocyte link
keratinocyte activation link inflammatory response link
Show evidence (2 references)
PMID:25274939 SUPPORT Human Clinical
"involves skin barrier disruption, cellular changes, and release of proinflammatory mediators."
This supports proinflammatory mediator release as a distinct ICD mechanism.
DOI:10.1155/2013/916497 SUPPORT Human Clinical
"Irritant contact dermatitis is a result of activated innate immune response to various external stimuli and consists of complex interplay which involves skin barrier disruption, cellular changes, and release of proinflammatory mediators."
This corroborates activated innate immune signaling and mediator release as central mechanisms in irritant contact dermatitis.
Innate inflammatory cell recruitment
Irritant-induced mediators recruit and activate inflammatory cells in skin after barrier injury.
dendritic cell link
inflammatory response link
Show evidence (1 reference)
PMID:25274939 SUPPORT Human Clinical
"release of proinflammatory mediators that directly recruit and activate T lymphocytes."
This supports recruitment and activation of inflammatory cells as a separate downstream ICD mechanism.
Hapten exposure
In allergic contact dermatitis, repeated skin contact with small reactive chemicals exposes the immune system to haptens and initiates sensitization.
Show evidence (1 reference)
PMID:19839974 SUPPORT Human Clinical
"Allergic contact dermatitis (ACD), one of the commonest occupational diseases, is a T-cell-mediated skin inflammation caused by repeated skin exposure to contact allergens, i.e. nonprotein chemicals called haptens."
This supports hapten exposure as the initiating event in allergic contact dermatitis.
Skin innate immune activation during sensitization
Early innate immune signaling in allergen-exposed skin shapes the sensitization phase and supports subsequent adaptive immune priming.
Langerhans cell link dendritic cell link
Show evidence (1 reference)
PMID:19839974 SUPPORT Human Clinical
"Recent advances in the pathophysiology of ACD have demonstrated the important role of skin innate immunity in the sensitization process"
This supports skin innate immune activation as a distinct mechanistic stage in allergic contact dermatitis sensitization.
Breakdown of regulatory T-cell-mediated hapten tolerance
Allergic contact dermatitis reflects failure of suppressive CD4-positive regulatory T-cell programs that normally prevent hapten priming and dampen eczema in sensitized individuals.
regulatory T cell link
Show evidence (1 reference)
PMID:19839974 SUPPORT Human Clinical
"Subsets of CD4+ T cells endowed with suppressive activity are responsible for both the down-regulation of eczema in allergic patients and the prevention of priming to haptens in nonallergic individuals."
This review identifies suppressive CD4-positive regulatory T-cell activity as a core counter-regulatory axis in allergic contact dermatitis.
Allergen-specific T-cell priming
During sensitization, antigen-presenting cells prime allergen-specific T cells, establishing the adaptive immune memory required for later flares.
Langerhans cell link dendritic cell link CD8-positive, alpha-beta T cell link
dendritic cell antigen processing and presentation link T cell activation link
Show evidence (1 reference)
PMID:19839974 SUPPORT Human Clinical
"Allergic contact dermatitis, also referred to as contact hypersensitivity, is mediated by CD8+ T cells, which are primed in lymphoid organs during the sensitization phase and are recruited in the skin upon re-exposure to the hapten."
This supports sensitization and T-cell priming as a discrete adaptive immune stage in allergic contact dermatitis.
Re-exposure-driven effector T-cell recruitment
Upon renewed hapten exposure, primed effector T cells re-enter skin and initiate the elicitation phase of allergic contact dermatitis.
CD8-positive effector T cell link
type IV hypersensitivity link
Show evidence (1 reference)
PMID:19839974 SUPPORT Human Clinical
"Allergic contact dermatitis, also referred to as contact hypersensitivity, is mediated by CD8+ T cells, which are primed in lymphoid organs during the sensitization phase and are recruited in the skin upon re-exposure to the hapten."
This supports effector T-cell recruitment to skin on hapten re-exposure as a separate mechanism node.
Resident memory T-cell flare activation
Epidermal resident memory CD8-positive T cells are activated in allergen-experienced skin and intensify local flare responses.
resident memory CD8-positive T cell link
Show evidence (1 reference)
PMID:37700557 SUPPORT Model Organism
"BACKGROUND: Allergic contact dermatitis (ACD) is an inflammatory disease with a complex pathophysiology in which epidermal-resident memory CD8+ T (TRM ) cells play a key role."
This supports resident memory CD8-positive T cells as a distinct driver of allergic contact dermatitis flares.
Mixed type 1 and type 3 cytokine and chemokine amplification
Activated effector and resident memory T cells amplify IFNg-, IL-17A-, IL-1beta-, and chemokine-rich inflammatory programs, with predominant type 1 and type 3 effector responses and lesser type 2 contributions.
T cell link neutrophil link
chemokine production link
Show evidence (2 references)
PMID:37700557 SUPPORT Model Organism
"We show that loss of CD100 results in a reduced inflammatory response to DNFB with impaired production of IFNγ, IL-17A, CXCL1, CXCL2, CXCL5, and IL-1β and decreased recruitment of neutrophils to the epidermis."
This supports amplification of inflammatory cytokines, chemokines, and neutrophil recruitment as a discrete downstream mechanism in allergic contact dermatitis.
DOI:10.1111/all.16642 SUPPORT Human Clinical
"All allergens exhibited mixed effector immune responses, mainly type 1 and 3 immunity, and, to a lesser extent, type 2 immunity."
This human transcriptomic study supports mixed type 1 and type 3 cytokine programs, with lesser type 2 contributions, during allergic contact dermatitis elicitation.
Fibroblast CXCL9/CXCL10 reinforcement
Dermal fibroblasts adopt a chemokine-producing inflammatory phenotype that reinforces type 1 lymphocyte polarization and sustains cutaneous inflammation.
fibroblast link T cell link
chemokine production link
Show evidence (1 reference)
PMID:39213029 SUPPORT Model Organism
"IFNγ treatment shifted dermal fibroblasts from collagen-producing to CXCL9/10-producing, which promoted T cell polarization toward the type-1 phenotype through a CXCR3-dependent mechanism."
This supports inflammatory fibroblast reprogramming as a distinct amplifying mechanism in allergic contact dermatitis.
Complement-associated sensory neuron activation
In allergic contact dermatitis, complement-associated neuroimmune signaling activates peripheral sensory pathways and contributes to itch generation.
sensory neuron link
Show evidence (1 reference)
PMID:34417985 SUPPORT Model Organism
"The complement system in sensory ganglion might play an essential role in forming pruritic and nociceptive sensations in ACD."
This supports complement-linked sensory pathway activation as a distinct neuroimmune mechanism in allergic contact dermatitis.
✶

Histopathology

2
Spongiotic dermatitis pattern
Allergic contact dermatitis falls within the broader histopathologic pattern of spongiotic or eczematous dermatitis, so biopsy findings require clinicopathologic correlation and exposure assessment rather than stand alone as a definitive discriminator.
Show evidence (1 reference)
PMID:39709083 SUPPORT Human Clinical
"BACKGROUND: Allergic contact dermatitis cannot be reliably differentiated from other forms of spongiotic/eczematous dermatitis by histology alone."
This supports spongiotic/eczematous dermatitis as the core histopathologic pattern of allergic contact dermatitis while emphasizing its limited specificity.
Epidermal spongiotic Langerhans cell collections
Within allergic contact dermatitis biopsies, epidermal collections of Langerhans cells are a supportive microscopic clue that can favor the diagnosis over other spongiotic dermatoses.
Show evidence (1 reference)
PMID:39709083 SUPPORT Human Clinical
"CONCLUSION: This largest study to date is the first to independently confirm Langerhans cell collections as the single histopathologic feature most closely associated with allergic contact dermatitis."
This supports epidermal spongiotic Langerhans cell collections as a biopsy feature that favors allergic contact dermatitis.
⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Contact Dermatitis Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
●

Phenotypes

4
Cardiovascular 1
Erythema FREQUENT Erythema (HP:0010783)
Erythematous patches or plaques are common at exposed or directly contacted skin sites.
Show evidence (1 reference)
PMID:9590995 SUPPORT Human Clinical
"Clinical signs include vesicles, papules, bullae, erythema, edema, scaling, and lichenification."
This review supports erythema as a common clinical sign of contact dermatitis, particularly irritant presentations.
Immune 1
Contact dermatitis OBLIGATE Contact dermatitis (HP:0032282)
Localized eczematous inflammation at sites of irritant or allergen exposure.
Show evidence (1 reference)
PMID:25102574 SUPPORT Human Clinical
"The two most common variants are irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD)."
This supports the broad clinical entity of contact dermatitis comprising allergic and irritant forms.
Integument 2
Pruritus FREQUENT Pruritus (HP:0000989)
Itching is a common symptom, especially in allergic forms and on thin skin sites such as the eyelids.
Show evidence (1 reference)
PMID:39941494 SUPPORT Human Clinical
"Background/Objectives: Eyelid dermatitis is an inflammatory disease affecting the palpebral skin characterized by itching, edema, and scaling of the periorbital area."
This human clinical series supports itching as a characteristic manifestation of contact dermatitis.
Scaling skin FREQUENT Scaling skin (HP:0040189)
Scaling commonly accompanies eczematous plaques and chronic hand or eyelid dermatitis.
Show evidence (1 reference)
PMID:39941494 SUPPORT Human Clinical
"Background/Objectives: Eyelid dermatitis is an inflammatory disease affecting the palpebral skin characterized by itching, edema, and scaling of the periorbital area."
This human clinical study supports scaling as a characteristic manifestation of contact dermatitis.
🧬

Genetic Associations

2
FLG loss-of-function variants and allergic sensitization susceptibility (Risk Factor)
Show evidence (1 reference)
PMID:23343419 SUPPORT Human Clinical
"FLG mutation carriers with self-reported dermatitis have an increased risk of contact sensitization to substances other than nickel"
This human population study supports FLG loss-of-function variants as a genetic risk factor for contact sensitization relevant to allergic contact dermatitis.
FLG loss-of-function variants and irritant contact dermatitis susceptibility (Risk Factor)
Show evidence (1 reference)
PMID:23039796 SUPPORT Human Clinical
"Our results indicate that both FLG mutations and AD increase the risk of ICD."
This occupational case-control study supports FLG variants as an independent genetic susceptibility factor for irritant contact dermatitis.
💊

Treatments

4
Allergen and irritant avoidance
Action: medical action avoidance MAXO:0001014
Identification and avoidance of the offending allergen or irritant is the central management strategy for both allergic and irritant contact dermatitis.
Show evidence (2 references)
PMID:25102574 SUPPORT Human Clinical
"Accurate diagnosis, avoidance of identified allergens and protection from irritants are the key to successful treatment."
This supports avoidance of sensitizers and irritants as first-line disease management.
PMID:9590995 SUPPORT Human Clinical
"Elimination of the offending agent and protection from further exposure are important in both diagnosis and management."
This independently supports exposure elimination and barrier protection as core treatment measures.
Topical corticosteroids
Action: topical corticosteroid therapy Ontology label: pharmacotherapy MAXO:0000058
Topical corticosteroids are used to treat inflammatory flares, especially in allergic contact dermatitis, while avoidance remains essential for long-term control.
Show evidence (1 reference)
PMID:31757238 SUPPORT Human Clinical
"Topical corticosteroids can be used to treat exacerbations, but should be avoided in long-term treatment."
This supports topical corticosteroids for short-term treatment of inflammatory exacerbations.
Topical calcineurin inhibitors
Action: topical calcineurin inhibitor therapy Ontology label: pharmacotherapy MAXO:0000058
Topical calcineurin inhibitors can be used as steroid-sparing topical therapy in selected allergic contact dermatitis settings, although evidence is mixed across allergens and agents. Tacrolimus improved chronic nickel-induced allergic contact dermatitis in a randomized trial, whereas pimecrolimus was ineffective for established Toxicodendron-induced allergic contact dermatitis in a small placebo-controlled study.
Show evidence (2 references)
PMID:16781290 SUPPORT Human Clinical
"CONCLUSIONS: Tacrolimus ointment 0.1% is well tolerated and significantly more effective than vehicle in treating chronically exposed, nickel-induced ACD."
This randomized clinical trial supports topical tacrolimus as an effective steroid-sparing option for chronic nickel-induced allergic contact dermatitis.
PMID:14700441 REFUTE Human Clinical
"CONCLUSIONS: The application of topical pimecrolimus is ineffective in the treatment of ongoing Toxicodendron-induced ACD."
This placebo-controlled human study refutes efficacy of pimecrolimus for established Toxicodendron-induced allergic contact dermatitis.
Systemic corticosteroids
Action: pharmacotherapy MAXO:0000058
Systemic corticosteroids are used for more severe or widespread flares of allergic contact dermatitis when topical treatment alone is insufficient, while culprit avoidance remains the core intervention.
Show evidence (1 reference)
DOI:10.3389/fmed.2023.1184289 SUPPORT Human Clinical
"The treatment goal is to avoid contact with the culprit agent and use topical and/or systemic corticosteroid therapy."
This review supports systemic corticosteroid therapy as a treatment option for allergic contact dermatitis alongside trigger avoidance.
🌍

Environmental Factors

13
Wet work and detergent exposure
exposure to detergent link
Repetitive wet work and exposure to soaps and detergents are common environmental drivers of irritant contact dermatitis, especially on the hands.
Show evidence (1 reference)
PMID:25102574 SUPPORT Human Clinical
"Cumulative effects of water, soaps and detergents are the most common cause of ICD which affects the hands more often than any other site."
This supports wet work and detergent exposure as major environmental triggers of irritant contact dermatitis.
Nickel exposure
exposure to nickel link
Exposure to nickel-containing jewelry, tools, and occupational metal sources is a common environmental trigger of allergic contact dermatitis.
Show evidence (1 reference)
DOI:10.3389/fmed.2023.1184289 SUPPORT Human Clinical
"Metals, especially nickel, fragrance mix, isothiazolinones, and para-phenylenediamine, are the most commonly positive allergens in patients patch tested for suspected ACD."
This review identifies nickel as one of the most common sensitizing exposures in allergic contact dermatitis.
Fragrance exposure
exposure to fragrance link
Fragrance-containing cosmetics, personal care products, and topical agents are common environmental triggers of allergic contact dermatitis.
Show evidence (1 reference)
DOI:10.3389/fmed.2023.1184289 SUPPORT Human Clinical
"Metals, especially nickel, fragrance mix, isothiazolinones, and para-phenylenediamine, are the most commonly positive allergens in patients patch tested for suspected ACD."
This review identifies fragrance mix as a common sensitizer in patients patch tested for allergic contact dermatitis.
Isothiazolinone exposure
Exposure to isothiazolinone preservatives in personal care, household, and industrial products is a recognized environmental trigger of allergic contact dermatitis.
Show evidence (2 references)
DOI:10.3389/fmed.2023.1184289 SUPPORT Human Clinical
"Metals, especially nickel, fragrance mix, isothiazolinones, and para-phenylenediamine, are the most commonly positive allergens in patients patch tested for suspected ACD."
This review identifies isothiazolinones as common sensitizing preservatives in allergic contact dermatitis.
PMID:41804652 SUPPORT Human Clinical
"The prevalence of CA to methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) was 4.58%, methylisothiazolinone (MI) was 5.48%, and benzisothiazolinone (BIT) was 2.09%."
This meta-analysis adds current human prevalence data showing multiple isothiazolinone preservatives are established sensitizers among dermatitis patients.
Mastisol adhesive exposure
exposure to glue link
Exposure to Mastisol liquid adhesive used for wound closure is a reported trigger of allergic contact dermatitis after surgical procedures.
Show evidence (1 reference)
PMID:30465037 SUPPORT Human Clinical
"We report on a rare case of allergic contact dermatitis (ACD) from Mastisol liquid adhesive."
This case report supports Mastisol as a specific adhesive trigger of allergic contact dermatitis.
2-octyl cyanoacrylate adhesive exposure
exposure to glue link
Exposure to 2-octyl cyanoacrylate topical skin adhesives used for surgical wound closure is an increasingly recognized trigger of allergic contact dermatitis, especially after repeat exposure.
Show evidence (2 references)
PMID:41784277 SUPPORT Human Clinical
"2-octyl cyanoacrylate (2-OCA) topical skin adhesives are widely used for surgical wound closure but are increasingly associated with allergic contact dermatitis (ACD)."
This systematic review supports 2-octyl cyanoacrylate as a specific surgical adhesive trigger of allergic contact dermatitis.
PMID:41784277 SUPPORT Human Clinical
"Re-exposure markedly increased risk, with reaction rates rising from 1-3% after initial exposure to >20% in staged or repeat procedures in several cohorts."
This supports repeat exposure as an important risk amplifier for cyanoacrylate-triggered allergic contact dermatitis.
Para-phenylenediamine exposure
Exposure to para-phenylenediamine, particularly in hair dyes and related products, is a common environmental trigger of allergic contact dermatitis.
Show evidence (1 reference)
DOI:10.3389/fmed.2023.1184289 SUPPORT Human Clinical
"Metals, especially nickel, fragrance mix, isothiazolinones, and para-phenylenediamine, are the most commonly positive allergens in patients patch tested for suspected ACD."
This review identifies para-phenylenediamine as a common sensitizer in allergic contact dermatitis.
Rubber accelerator exposure
Exposure to rubber accelerators in gloves, footwear, and occupational materials is a common environmental trigger of allergic contact dermatitis.
Show evidence (1 reference)
PMID:25102574 SUPPORT Human Clinical
"Nickel, fragrances, rubber accelerators and biocides are the most common sensitisers in ACD."
This review identifies rubber accelerators as common sensitizers in allergic contact dermatitis.
Biocide exposure
Exposure to biocides and preservative chemicals in occupational and consumer products is a common environmental trigger of allergic contact dermatitis.
Show evidence (1 reference)
PMID:25102574 SUPPORT Human Clinical
"Nickel, fragrances, rubber accelerators and biocides are the most common sensitisers in ACD."
This review identifies biocides as common sensitizers in allergic contact dermatitis.
Repeated and high-concentration allergen exposure
Repeated contact and higher local concentrations of potential allergens increase the probability of sensitization and later allergic flares.
Show evidence (1 reference)
PMID:25102574 SUPPORT Human Clinical
"Frequent exposure and high concentrations of potential allergens increase the risk of sensitisation."
This supports repeated or intense exposure as an environmental risk factor for allergic sensitization.
Toxicodendron exposure
exposure to allergen link
Exposure to Toxicodendron plants such as poison ivy, poison oak, and poison sumac is a common environmental trigger of allergic contact dermatitis.
Show evidence (2 references)
PMID:14700441 SUPPORT Human Clinical
"Plants of the Toxicodendron species cause allergic contact dermatitis (ACD) in 50% to 70% of the population."
This supports Toxicodendron plant exposure as a common and clinically important trigger of allergic contact dermatitis.
PMID:27548435 SUPPORT Human Clinical
"Among various urushiol congeners, we identified diunsaturated pentadecylcatechol (C15:2) as the dominant antigen for CD1a-restricted T cells."
This supports urushiol III, the diunsaturated pentadecylcatechol congener, as a specific Toxicodendron allergen linked to poison ivy dermatitis.
Lime and other psoralen-rich citrus exposure with ultraviolet light
Contact with lime juice or peel followed by ultraviolet exposure can trigger phytophotodermatitis, a phototoxic contact reaction that may be mistaken for allergic dermatitis.
Show evidence (1 reference)
PMID:41064302 SUPPORT Human Clinical
"Lime-induced phytophotodermatitis, sometimes called "lime disease" or "margarita photodermatitis," is one of the most common forms, caused by furocoumarins in lime juice or peel."
This case report supports lime-derived psoralen exposure with UV light as a specific trigger of photocontact dermatitis.
Mare's milk soap exposure
Soap products containing mare's milk have been reported as specific triggers of allergic contact dermatitis in sensitized individuals.
Show evidence (1 reference)
PMID:40921440 SUPPORT Human Clinical
"Allergic Contact Dermatitis Triggered by a Mare's Milk-Based Soap."
The report title directly identifies mare's milk-based soap as a documented trigger of allergic contact dermatitis.
🔀

Differential Diagnoses

3

Conditions with similar clinical presentations that must be differentiated from Contact Dermatitis:

Atopic dermatitis MONDO:0004980
Overlapping Features Atopic dermatitis can overlap with contact dermatitis when patients present with chronic pruritic eczema, and the two disorders may coexist in the same patient.
Distinguishing Features
  • Atopic dermatitis more often shows a chronic relapsing endogenous eczema pattern with broader flexural involvement and an atopic background.
  • Contact dermatitis is more tightly linked to external exposures and tends to localize to the area of contact with the exogenous trigger.
Show evidence (2 references)
PMID:38713001 SUPPORT Human Clinical
"Furthermore, other conditions, with different pathogenesis and treatment, may clinically simulate contact dermatitis."
This task-force review supports atopic dermatitis as part of the clinical differential diagnosis for contact dermatitis.
PMID:38713001 SUPPORT Human Clinical
"Although irritant and allergic contact dermatitis have a different pathogenesis, both are characterized by a rather typical morphology, are triggered by external factors and tend to occur primarily in the area of contact with the exogenous agent."
This supports exposure-linked localization as a key feature that helps distinguish contact dermatitis from broader endogenous eczema such as atopic dermatitis.
Psoriasis MONDO:0005083
Overlapping Features Psoriasis can mimic chronic scaly dermatitis, especially on the hands or scalp, but it is a distinct immune-mediated papulosquamous disorder rather than an exposure-driven eczema.
Distinguishing Features
  • Psoriasis more often produces sharply demarcated plaques with thick adherent scale and characteristic extensor, scalp, or nail involvement.
  • Contact dermatitis is usually linked to a relevant irritant or allergen exposure history and improves when the offending exposure is removed.
Show evidence (2 references)
PMID:38713001 SUPPORT Human Clinical
"Furthermore, other conditions, with different pathogenesis and treatment, may clinically simulate contact dermatitis."
This practical review supports psoriasis as a plausible simulator within the differential diagnosis of contact dermatitis.
PMID:25102574 SUPPORT Human Clinical
"Contact dermatitis results from skin contact with an exogenous substance."
This supports exogenous exposure as a distinguishing feature of contact dermatitis relative to psoriasis.
Tinea corporis Not Yet Curated MONDO:0001461
Overlapping Features Dermatophyte infection can resemble localized eczematous dermatitis when lesions are annular and scaly, particularly if exposure history is unclear.
Distinguishing Features
  • Tinea corporis typically shows an annular advancing border with central clearing and is confirmed by fungal testing when needed.
  • Contact dermatitis is evaluated through exposure history and, for allergic disease, patch testing rather than mycologic testing.
Show evidence (2 references)
PMID:38713001 SUPPORT Human Clinical
"Furthermore, other conditions, with different pathogenesis and treatment, may clinically simulate contact dermatitis."
This supports superficial fungal infection as part of the broader mimic set that must be separated from contact dermatitis.
PMID:31757238 SUPPORT Human Clinical
"Diagnosis is based on a thorough history, physical examination, and patch testing."
This supports patch testing and exposure-based evaluation as distinguishing elements for allergic contact dermatitis.
📊

Related Datasets

2
Genome-Wide Profiling of Lesional and Non-Lesional Skin from Atopic Dermatitis, Psoriasis, and Contact Dermatitis Skin GEO:GSE153007
Comparative human skin transcriptomic dataset spanning lesional and non-lesional samples from contact dermatitis alongside atopic dermatitis and psoriasis, enabling cross-disease comparison of inflammatory programs.
Homo sapiens MICROARRAY
Conditions: contact dermatitis skin non-lesional skin atopic dermatitis skin psoriasis skin
Dataset record: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE153007
Show evidence (1 reference)
GEO:GSE153007 SUPPORT Human Clinical
"Genome-Wide Profiling of Lesional and Non-Lesional Skin from Atopic Dermatitis, Psoriasis, and Contact Dermatitis Skin"
This GEO record supports a disease-relevant comparative skin transcriptomic dataset that explicitly includes contact dermatitis samples.
Inhibition of DYRK1B suppresses inflammation in allergic contact dermatitis model and Th1/Th17 immune response GEO:GSE215457
Transcriptomic dataset associated with DYRK1B inhibition experiments used to interrogate T-cell inflammatory programs relevant to allergic contact dermatitis and Th1/Th17 polarization.
Homo sapiens BULK RNA SEQ
Dataset record: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE215457
Show evidence (1 reference)
GEO:GSE215457 SUPPORT In Vitro
"To investigate the inhibition effect of DYRK1B kinase function on human naïve CD4+ T cell differetionation which stimulated under Treg polarizing condition for 24 hours."
This GEO record supports a human T-cell transcriptomic dataset tied to mechanistic allergic contact dermatitis work on inflammatory T-cell polarization.
🔬

Clinical Trials

2
NCT05535738 PHASE_II RECRUITING
Recruiting combined phase 2/3 mechanistic interventional study using a controlled contact dermatitis model with biologic pretreatment and suction blister-based skin sampling to dissect cutaneous inflammatory pathways.
Target Phenotypes: Contact dermatitis ↗
Show evidence (1 reference)
clinicaltrials:NCT05535738 SUPPORT Human Clinical
"The purpose of this study is to answer: how do inflammation and anti-inflammatory skin therapies work in the skin?"
This official study record supports a currently recruiting interventional trial that uses a contact dermatitis model to study inflammatory skin responses.
NCT02778711 PHASE_III UNKNOWN
Registered phase 3 interventional study evaluating secukinumab as a targeted treatment strategy for severe allergic contact dermatitis.
Target Phenotypes: Pruritus ↗ Erythema ↗
Show evidence (1 reference)
clinicaltrials:NCT02778711 SUPPORT Human Clinical
"The purpose of this study is to assess the efficacy of anti-IL 17 treatment (secukinumab) in patients with known severe allergic contact dermatitis (ACD)."
This official study record supports a registered interventional trial directly focused on severe allergic contact dermatitis.
📚

Literature Summaries

1
Asta ▸
Asta Literature Retrieval: Contact Dermatitis pathophysiology mechanisms phenotypes
Asta Scientific Corpus Retrieval 65 citations 2026-03-13T14:45:20.314995

Asta Literature Retrieval: Contact Dermatitis pathophysiology mechanisms phenotypes

This report is retrieval-only and is generated directly from Asta results.

  • Papers retrieved: 65
  • Snippets retrieved: 20

Relevant Papers

[1] Allergic contact dermatitis: pathophysiology applied to future therapy

  • Authors: Lily Li, P. Cruz
  • Year: 2004
  • Venue: Dermatologic Therapy
  • URL: https://www.semanticscholar.org/paper/22049b3a38538ebb26c3d0f96425fa4d5b63f5b8
  • DOI: 10.1111/j.1396-0296.2004.04023.x
  • PMID: 15186367
  • Citations: 34
  • Influential citations: 1
  • Summary: The pathogenesis and current treatment of allergic contact dermatitis and speculates on the prospects for improved future therapy are reviewed.
  • Evidence snippets:
  • Snippet 1 (score: 0.534) > Allergic contact dermatitis: pathophysiology applied to future therapy
  • Snippet 2 (score: 0.508) > ABSTRACT:  Contact dermatitis is a common reason for patient visits to primary‐care clinics and represents up to 7% of all dermatologic consultations in the US. Substantial progress has been made in elucidating the pathophysiology of contact dermatitis, particularly the allergic form. A better understanding of pathologic mechanisms has led to improved management of cases and will continue to advance treatment modalities. The present paper reviews the pathogenesis and current treatment of allergic contact dermatitis and speculates on the prospects for improved future therapy.

[2] Coexistence of Allergic Contact Dermatitis and Immediate-Type Hypersensitivity Reactions, Two Contrasting Immunological Responses: A Literature Review

  • Authors: Unknown authors
  • Year: 2025
  • Venue: Journal of Dermatology Research
  • URL: https://www.semanticscholar.org/paper/4f5a6db9a2e9066e824d67d0f423a12b83564872
  • DOI: 10.46889/jdr.2025.6315
  • Summary: A careful clinical/anamnestic evaluation would be appropriate for each dermatological patient in order to detect the possible presence of both hypersensitivities, as well as mechanisms operating outside the classic Th1/Th2 paradigm, which do not appear to have effective inhibitory activity on either allergic reaction.

[3] CD100 boosts the inflammatory response in the challenge phase of allergic contact dermatitis in mice

  • Authors: V. Mraz, A. B. Funch, M. H. Jee, A. Ø. Gadsbøll, J. F. Weber et al.
  • Year: 2023
  • Venue: Contact Dermatitis
  • URL: https://www.semanticscholar.org/paper/20eb92e93ffc7d094063755381dd37b30248e7ec
  • DOI: 10.1111/cod.14414
  • PMID: 37700557
  • Citations: 1
  • Summary: Allergic contact dermatitis (ACD) is an inflammatory disease with a complex pathophysiology in which epidermal‐resident memory CD8+ T (TRM) cells play a key role. The mechanisms involved in the activation of CD8+ TRM cells during allergic flare‐up responses are not understood.

[4] miRNAs’ Cross-Involvement in Skin Allergies: A New Horizon for the Pathogenesis, Diagnosis and Therapy of Atopic Dermatitis, Allergic Contact Dermatitis and Chronic Spontaneous Urticaria

  • Authors: Raffaele Brancaccio, G. Murdaca, Rossella Casella, Teresa Loverre, L. Bonzano et al.
  • Year: 2023
  • Venue: Biomedicines
  • URL: https://www.semanticscholar.org/paper/00f11932eb7962608a2e1409761373dd1a37dbb7
  • DOI: 10.3390/biomedicines11051266
  • PMID: 37238937
  • PMCID: 10216116
  • Citations: 6
  • Influential citations: 2
  • Summary: A narrative review using the Pubmed and Embase scientific databases and search engines to find the most relevant miRNAs related to the pathophysiology, severity and prognosis of skin conditions.

[5] Tissue-Resident Trouble: How TRM Cells Drive Allergic Contact Dermatitis

  • Authors: William Steiner Olsen, Carsten Geisler, C. Bonefeld, M. H. Jee
  • Year: 2025
  • Venue: Current Treatment Options in Allergy
  • URL: https://www.semanticscholar.org/paper/68622e9adcdaf23c3843419faf0acd16f4e1ec62
  • DOI: 10.1007/s40521-025-00392-1
  • Summary: This review investigates how TRM cells differ from central and effector memory T (TCM and TEM) cells in their contributions to disease recurrence, severity, and chronicity in ACD.

[6] IL22RA2 is a Smad7 target mediating alleviation of dermatitis and psoriatic phenotypes in mice.

  • Authors: Yao Ke, Ben-Zheng Li, Khoa Nguyen, Donna Wang, Suyan Wang et al.
  • Year: 2023
  • Venue: The Journal of investigative dermatology
  • URL: https://www.semanticscholar.org/paper/66b0661d6f01bd4bfdfc9a3571630021beac6100
  • DOI: 10.1016/j.jid.2023.04.029
  • PMID: 37211203
  • Citations: 5
  • Summary: This study identified the anti-inflammation functional domain of Smad7 and suggests mechanism and feasibility for developing Smad 7-based biologics as a topical therapy for skin inflammatory disorders.

[7] Recent Developments and Advances in Atopic Dermatitis: A Focus on Epidemiology, Pathophysiology, and Treatment in the Pediatric Setting

  • Authors: L. Eichenfield, Stephen Stripling, Selwyn Fung, A. Cha, Andryann O’Brien et al.
  • Year: 2022
  • Venue: Paediatric Drugs
  • URL: https://www.semanticscholar.org/paper/aff13e2dcb3dccbf496f436dd93f3bf898215377
  • DOI: 10.1007/s40272-022-00499-x
  • PMID: 35698002
  • PMCID: 9191759
  • Citations: 80
  • Influential citations: 5
  • Summary: Recent advances in scientific research regarding the mechanisms involved in the pathogenesis of atopic dermatitis that have resulted in the discovery of novel therapeutic targets and the development of targeted biologic therapies with the potential to revolutionize AD therapy are highlighted.

[8] Eyelid Contact Dermatitis: 25-Year Single-Center Retrospective Study

  • Authors: G. Rubegni, Tommaso Padula, L. Calabrese, M. D’Onghia, L. Tognetti et al.
  • Year: 2025
  • Venue: Journal of Clinical Medicine
  • URL: https://www.semanticscholar.org/paper/58ddf9aaebf7e17e684028a21a25b94147f5ac43
  • DOI: 10.3390/jcm14030823
  • PMID: 39941494
  • PMCID: 11818699
  • Citations: 3
  • Influential citations: 1
  • Summary: The haptens identified in eyelid ACD largely overlap with those found in other body regions, including metals, fragrances, and preservatives, however, the unique characteristics of eyelid skin and hand–eye contact patterns play a significant role in sensitization.

[9] Tolerogenic phenotype of dendritic cells is induced after hapten sensitization followed by attenuated contact hypersensitivity response in atopic dermatitis model NC/Nga mice.

  • Authors: Kanako Nakayama, Hiroe Tetsu, Taku Nishijo, T. Yuki, Masaaki Miyazawa
  • Year: 2023
  • Venue: Biochemical and biophysical research communications
  • URL: https://www.semanticscholar.org/paper/84f61913e47b4dff53340c5de76caf11475c2196
  • DOI: 10.1016/j.bbrc.2023.08.042
  • PMID: 37611349
  • Summary: Allergic contact dermatitis (ACD) and atopic dermatitis (AD) are common inflammatory diseases. We previously reported attenuated contact hypersensitivity (CHS) responses in AD model mice using 2,4-dinitrofluorobenzene, reflecting clinical experiments. However, previous studies have not addressed the commonality of findings across haptens and mechanisms focused on dendritic cells (DCs). Thus, this study evaluated CHS responses to fluorescein isothiocyanate (FITC) and DC migration and maturatio...

[10] Defining cell type-specific immune responses in a mouse model of allergic contact dermatitis by single-cell transcriptomics

  • Authors: Youxi Liu, Meimei Yin, X. Mao, Shuai Wu, Shuangping Wei et al.
  • Year: 2024
  • Venue: eLife
  • URL: https://www.semanticscholar.org/paper/f5fe2c2956a5a37b8d84019c22a12ed15d401c47
  • DOI: 10.7554/eLife.94698
  • PMID: 39213029
  • PMCID: 11364439
  • Citations: 4
  • Summary: The results define the cell type-specific immune responses in ACD, and recognize an indispensable role of dermal fibroblasts in shaping the development of type-1 skin inflammation through the IFNGR-CXCR3 signaling circuit during ACD pathogenesis.

[11] Atopic dermatitis phenotypes and the need for personalized medicine

  • Authors: B. Cabanillas, A. Brehler, N. Novak
  • Year: 2017
  • Venue: Current Opinion in Allergy and Clinical Immunology
  • URL: https://www.semanticscholar.org/paper/c674390a42ad43c1458daa6d41da388adafeeb41
  • DOI: 10.1097/ACI.0000000000000376
  • PMID: 28582322
  • PMCID: 5515628
  • Citations: 129
  • Influential citations: 6
  • Summary: Current standard treatments of atopic dermatitis do not focus on the individual pathogenesis of the disease, so the development of targeted, phenotype-specific therapies has the potential to open a new promising era of individualized treatment of atopy dermatitis.

[12] Addressing Unmet Needs in Atopic Dermatitis: Evaluating Disease-Modifying Capabilities of Current and Emerging Therapies

  • Authors: S. G. Brooks, Lourdes M Lopez, K. Mashoudy, G. Yosipovitch, T. Czarnowicki
  • Year: 2024
  • Venue: Dermatitis®
  • URL: https://www.semanticscholar.org/paper/8f4167f3fe30c1c12036440fa0b4c6fb5980dbd0
  • DOI: 10.1089/derm.2024.0261
  • PMID: 39465269
  • Citations: 2
  • Summary: Findings include variability in AD pathophysiology and phenotypes across different age groups and ethnicities, indicating a need for research into endotype-specific treatments and evidence suggesting that select current drugs may offer long-term disease-modifying benefits.

[13] Annexin 1 Reduces Dermatitis-Induced Itch and Cholestatic Itch through Inhibiting Neuroinflammation and Iron Overload in the Spinal Dorsal Horn of Mice

  • Authors: Tang Li, Lingyue Hu, Chao Qin, Yuanjie Li, Zhenhua Song et al.
  • Year: 2024
  • Venue: Brain Sciences
  • URL: https://www.semanticscholar.org/paper/0b6da81601c773ed9aa1deab35f1972ba60accb7
  • DOI: 10.3390/brainsci14050440
  • PMID: 38790419
  • PMCID: 11118431
  • Citations: 2
  • Summary: This current research indicates that ANXA1 protects against the beginning and maintenance of long-term dermatitis-induced itch and cholestatic itch, which may occur via the spinal suppression of IL-17-mediated neuroinflammation, astrocyte activation and iron overload.

[14] Effector and regulatory mechanisms in allergic contact dermatitis

  • Authors: M. Vocanson, Ana Hennino, A. Rozieres, G. Poyet, Jean-François Nicolas
  • Year: 2009
  • Venue: Allergy
  • URL: https://www.semanticscholar.org/paper/906592a7d085770b16e7203be02bf8e91fb6c9f3
  • DOI: 10.1111/j.1398-9995.2009.02082.x
  • PMID: 19839974
  • Citations: 332
  • Influential citations: 16
  • Summary: ACD should be considered as a breakdown of the skin immune tolerance to haptens, and the nature, the mode and the site of action of the regulatory T cells that control the skin inflammation are addressed with the aim of developing new strategies of tolerance induction in allergic patients.

[15] Contact dermatitis I. Pathophysiology of contact sensitivity.

  • Authors: M. Krasteva, J. Kehren, M. Ducluzeau, M. Sayag, Marco Cacciapuoti et al.
  • Year: 1999
  • Venue: European journal of dermatology : EJD
  • URL: https://www.semanticscholar.org/paper/1949151c9f02e44825a44f440f5b96745e76a7b7
  • PMID: 9920992
  • Citations: 87
  • Influential citations: 3
  • Summary: Allergic contact dermatitis is one of the most common skin diseases, with a great socio-economic impact and according to the pathophysiological mechanisms involved, two main types of CD may be distinguished: allergicContact dermatitis (ACD) and irritant contact dermatritis (ICD).

[16] Integrated Mechanisms of Cutaneous Immunity: From Barrier Dysfunction to Neuroimmune Crosstalk in Inflammatory Skin Disease

  • Authors: Andrés Felipe, Herrera Homez, Hillary Yahiry, Mejía Montiel, María Camila et al.
  • Year: 2025
  • Venue: IECCMEXICO
  • URL: https://www.semanticscholar.org/paper/ec5216fb1359be98869809c9552584fae7a688b6
  • DOI: 10.64784/064
  • Summary: This review synthesizes contemporary evidence on epidermal barrier dysfunction, microbiome dysbiosis, antigen-presenting cell networks, tissue-resident memory T cells, and neuroimmune signaling to construct a comprehensive model explaining the pathophysiology of major inflammatory dermatoses, including atopic dermatitis, psoriasis, and allergic contact dermatitis.

[17] Proteome Profile of Trigeminal Ganglion in Murine Model of Allergic Contact Dermatitis: Complement 3 Pathway Contributes to Itch and Pain Sensation

  • Authors: Wenliang Su, Jiawen Yu, Xiuhua Zhang, Lulu Ma, Yuguang Huang
  • Year: 2021
  • Venue: Neurotoxicity Research
  • URL: https://www.semanticscholar.org/paper/b923d075ae734e17d016ce18469b05cda512f8bc
  • DOI: 10.1007/s12640-021-00384-4
  • PMID: 34417985
  • Citations: 6
  • Summary: The complement system in sensory ganglion might play an essential role in forming pruritic and nociceptive sensations in ACD, and proteins involved in the complement and coagulation cascades were notably changed in the KEGG enrichment analysis.

[18] Pathophysiologic Mechanisms and Targeted Treatments Associated with the Nervous System in Cutaneous Allergic Diseases

  • Authors: Han-jun Zhang, Weiyi Xiang, Yi Tong, Xian Jiang, Linghong Guo
  • Year: 2025
  • Venue: Clinical Reviews in Allergy & Immunology
  • URL: https://www.semanticscholar.org/paper/b8e543a81e134152b53d45c5a862e9570583f910
  • DOI: 10.1007/s12016-025-09115-5
  • PMID: 41405747
  • Summary: This review systematically examines atopic dermatitis, contact dermatitis, and urticaria, integrating insights into peripheral pathways-mediated by sensory neurons, cytokine networks, and immune cells-and central mechanisms involving the hypothalamic-pituitary-adrenal axis and higher neural circuits.

[19] Biocompatibility and Post-Marketing Surveillance Study of Emollient Plus Medical Device Cream Containing Oligofructans from Ophiopogon japonicus and Acetyl Heptapeptide-4 in Atopic Dermatitis Skin Care

  • Authors: Michał Rachalewski, M. Pasikowska-Piwko, Renata Dębowska, Iwona Marczak, Karolina Lendzion et al.
  • Year: 2024
  • Venue: Cosmetics
  • URL: https://www.semanticscholar.org/paper/a98bb9c7dd51c9436d48646735bcada6a07914b6
  • DOI: 10.3390/cosmetics11040136
  • Summary: In vitro/ex vivo assays confirmed that the product is safe, non-irritant, and does not stimulate the production of proinflammatory cytokines, and according to the local SCORAD, the symptoms of AD were alleviated.

[20] Atopic Dermatitis and Allergic Contact Dermatitis in Pregnancy

  • Authors: S. Mawhirt, L. Fonacier
  • Year: 2018
  • Venue: Asthma, Allergic and Immunologic Diseases During Pregnancy
  • URL: https://www.semanticscholar.org/paper/ec9bbaf02adabb2b862f37b97ce3ed8fcf98521d
  • DOI: 10.1007/978-3-030-03395-8_7
  • Citations: 2
  • Summary: Treatment options for AD and ACD are relatively limited in the pregnant patient, given the potential fetal adverse effects of several therapeutic options, especially for moderate-to-severe cases.

[21] Atopic dermatitis: an expanding therapeutic pipeline for a complex disease

  • Authors: T. Bieber
  • Year: 2021
  • Venue: Nature Reviews. Drug Discovery
  • URL: https://www.semanticscholar.org/paper/00c7af7588e9c52d8551b3bd721794fad6a7c59b
  • DOI: 10.1038/s41573-021-00266-6
  • PMID: 34417579
  • PMCID: 8377708
  • Citations: 471
  • Influential citations: 25
  • Summary: This Review assesses the various strategies and novel agents currently being investigated for AD and highlights the potential for a precision medicine approach to enable prevention and more effective long-term control of this complex disease.

[22] Investigation of the underlying mechanisms leading to the development of incontinence-associated dermatitis.

  • Authors: Sofoklis Koudounas
  • Year: 2019
  • Venue: Unknown venue
  • URL: https://www.semanticscholar.org/paper/9eca7319be9091fb878e659c8becf4cc704083ee
  • Citations: 2
  • Summary: The data add to the scientific body of evidence and propose that the damage caused by frequent cleansing activities and the release of inflammatory biomarkers are two mechanisms implicated in the pathophysiology of IAD.

[23] Ghrelin protects against contact dermatitis and psoriasiform skin inflammation by antagonizing TNF-α/NF-κB signaling pathways

  • Authors: Ruize Qu, Xiaomin Chen, Jing Hu, Yufeng Fu, Jiangfan Peng et al.
  • Year: 2019
  • Venue: Scientific Reports
  • URL: https://www.semanticscholar.org/paper/e89b1847ace8d9bbf1aad0b38564730621f537aa
  • DOI: 10.1038/s41598-018-38174-2
  • PMID: 30718736
  • PMCID: 6362006
  • Citations: 44
  • Influential citations: 1
  • Summary: Exogenous ghrelin attenuated the inflammatory reaction induced by TNF-α in RAW264.7 cells and may represent a potential molecular target for the prevention and treatment of inflammatory skin diseases, including contact dermatitis and psoriasis.

[24] Melasma: Pathophysiology, Clinical Picture and Treatment Lines Overview

  • Authors: H. H. Sabry, Mohammad bag Khaleel Abbo, S. Ibrahim
  • Year: 2025
  • Venue: Benha Journal of Applied Sciences
  • URL: https://www.semanticscholar.org/paper/07c29c0c5a9091dfc76999d4007960f0ac942f85
  • DOI: 10.21608/bjas.2025.363341.1599
  • Summary: Treating hyperpigmentation alone may not be beneficial unless combined with regenerative methods and photoprotection, so the treatment plan begins with risk factor management and the implementation of strong UV protection measures.

[25] Exploring the pathophysiological mechanisms and wet biomarkers of VPS13A disease

  • Authors: Jingqi Lin, Hongmei Meng, Nilupaer Shafeng, Jiaai Li, Huaiyu Sun et al.
  • Year: 2024
  • Venue: Frontiers in Neurology
  • URL: https://www.semanticscholar.org/paper/4c1641eeeb6123c32c4427875986aad04f4691c9
  • DOI: 10.3389/fneur.2024.1482936
  • PMID: 39659962
  • PMCID: 11628379
  • Citations: 3
  • Summary: A review of recent studies on VPS13A protein and ChAc is presented, focusing on the potential role of the VPS13A protein in pathophysiology of ChAc and also review the known and potential wet biomarkers of ChAc to enhance the comprehension of this rare disease.

[26] Euphorbia myrsinites Sap-Induced Phytodermatitis: A Prototype of Irritant Contact Dermatitis?

  • Authors: B. Weber, C. Sinz, W. Bauer, S. Kancz, H. Kittler et al.
  • Year: 2019
  • Venue: Dermatitis
  • URL: https://www.semanticscholar.org/paper/95a35331bd42a09a5f929ee67682e961ab267767
  • DOI: 10.1097/DER.0000000000000454
  • PMID: 30829799
  • Citations: 6
  • Summary: The reported findings support the primarily toxic irritant nature of EM sap–induced phytodermatitis, and the contribution of ingenol mebutate to (nontoxic) proinflammatory effects remains to be elucidated.

[27] 014 IL-27 induces IL-15 production to facilitate T cell survival in allergic contact dermatitis

  • Authors: J. Suwanpradid, M. Lee, P. Hoang, J. Kwock, L. Floyd et al.
  • Year: 2020
  • Venue: Journal of Investigative Dermatology
  • URL: https://www.semanticscholar.org/paper/b72deb005b57058b455da1dc21062fc8eccb8246
  • DOI: 10.1016/j.jid.2020.03.016
  • Summary: Results suggest that differential methylation in KC may underly dysregulated apoptosis and female bias of CLE, and psoriasis patient serum biomarkers may be useful for separating response to therapy endotypes.

[28] Allergic contact dermatitis due to neem oil: A case report and mini‐review

  • Authors: R. Tamagawa‐Mineoka, K. Masuda, N. Katoh
  • Year: 2019
  • Venue: The Journal of Dermatology
  • URL: https://www.semanticscholar.org/paper/255502506ffb9fd07d341b36f9a9d1fd021804d7
  • DOI: 10.1111/1346-8138.15182
  • PMID: 31823408
  • Citations: 7
  • Summary: To the best of the authors' knowledge, this is the first case report of both urticarial papules and hypohidrosis being successfully treated with omalizumab, which might have influenced both diseases in this patient.

[29] When Foods Cause Itch: Clinical Characteristics, Pathophysiology, and Recommendations for Food-Induced Skin and Mucosal Pruritus

  • Authors: A. Vander Does, T. Ju, G. Yosipovitch
  • Year: 2023
  • Venue: Dermatitis
  • URL: https://www.semanticscholar.org/paper/b6fc6bbeaa56996a6fde346fb7623ef82e22f7da
  • DOI: 10.1089/DERM.0000000000000916
  • PMID: 36705658
  • Summary: For patients presenting with urticaria, generalized pruritus, oral pruritus, or dermatitis, a thorough history is warranted, and possible food associations should be considered and assessed, and possible food associations should be considered and assessed.

[30] THE ROLE OF KERATINOCYTES IN THE PATHOPHYSIOLOGY OF CONTACT DERMATITIS

  • Authors: A. Gaspari
  • Year: 1997
  • Venue: Immunology and Allergy Clinics of North America
  • URL: https://www.semanticscholar.org/paper/cc7b50b3524a542b62ba381f073e39a5a1577a1e
  • DOI: 10.1016/S0889-8561(05)70316-7
  • Citations: 22
  • Summary: The various contact dermatitides are outlined, then compared to compare the features of ICD and ACD, and the immune mechanisms of contact dermatitis are outline, with special emphasis on the role of keratinocytes.

[31] Perspectives in the Molecular Mechanisms Underlying Anaphylaxis.

  • Authors: V. Esteban, F. Skrabski, C. Perales-Chordá, Y. Puente-Crespo, R. Muñoz-Cano et al.
  • Year: 2025
  • Venue: Journal of investigational allergology & clinical immunology
  • URL: https://www.semanticscholar.org/paper/64a2b1dfff977fafb355e1e9b4a18d0bab51ea13
  • DOI: 10.18176/jiaci.1080
  • PMID: 40576298
  • Citations: 5
  • Summary: Recognition of cellular and molecular signaling mechanisms will enable better patient phenotyping and management in clinical practice, and genetic factors, such as hereditary a-tryptasemia, are associated with risk of severe reaction.

[32] The mystery of methylmercury-perturbed calcium homeostasis: AMPK-DRP1-dependent mitochondrial fission initiates ER-mitochondria contact formation.

  • Authors: Yi Hu, Changsong Tian, Fang Chen, A. Zhang, Wenjuan Wang
  • Year: 2024
  • Venue: The Science of the total environment
  • URL: https://www.semanticscholar.org/paper/bce46a7c7d71a5d55cd7ab82b148da41154b719d
  • DOI: 10.1016/j.scitotenv.2024.171398
  • PMID: 38442753
  • Citations: 13
  • Summary: A novel role of AMPK-DRP1-mediated mitochondrial fragmentation in the coupling of ER-mitochondrial calcium microdomains in MeHg-induced neurotoxicity is revealed, providing valuable insights for the development of strategies to regulate mitochondrial imbalances in neurological diseases.

[33] Mechanisms of contact sensitization offer insights into the role of barrier defects versus intrinsic immune abnormalities as drivers of atopic dermatitis

  • Authors: N. Dhingra, Nicholas Gulati, E. Guttman‐Yassky
  • Year: 2013
  • Venue: The Journal of investigative dermatology
  • URL: https://www.semanticscholar.org/paper/7e6041bef9a50ab503d4768e54901a8ea6288acb
  • DOI: 10.1038/jid.2013.239
  • PMID: 24030647
  • PMCID: 3773606
  • Citations: 39
  • Influential citations: 1
  • Summary: In this issue, Newell et al. (2013) used an experimental contact sensitization model with dinitrochlorobenzene (DNCB) to gain insight into the unique immune phenotype of AD patients.
  • Evidence snippets:
  • Snippet 1 (score: 0.410) > Atopic dermatitis (AD) is a common inflammatory skin disease characterized by wet, oozing, erythematous, pruritic lesions in the acute stage and xerotic, lichenified plaques in the chronic stage. It frequently coexists with asthma and allergic rhinitis, sharing some mechanistic features with these diseases as part of the "atopic march." Controversy exists as to whether immune abnormalities, epidermal barrier defects, or both are the primary factors responsible for disease pathogenesis. In AD patients, there is often a coexisting irritant contact dermatitis (ICD) or allergic contact dermatitis (ACD) that is sometimes clinically difficult to distinguish from AD. ACD shares molecular mechanisms with AD, including increased cellular infiltrates and cytokine activation (Gittler et al., 2013). In this issue, Newell et al. (2013) used an experimental contact sensitization model with dinitrochlorobenzene (DNCB) to gain insight into the unique immune phenotype of AD patients.

[34] Atopic dermatitis endotypes: knowledge for personalized medicine

  • Authors: Jihyun Kim, K. Ahn
  • Year: 2022
  • Venue: Current Opinion in Allergy and Clinical Immunology
  • URL: https://www.semanticscholar.org/paper/662d7d7fbd9665420630f8c780ae7d06995c3d5c
  • DOI: 10.1097/ACI.0000000000000820
  • PMID: 35152229
  • Citations: 14
  • Summary: Cytokine-based endotypes in different age groups or ethnic groups have contributed to expanding the understanding of atopic dermatitis and provide endotype-driven targeted therapies for personalized medicine.

[35] Recent Advancements in the Atopic Dermatitis Mechanism.

  • Authors: Marianna Savva, Nikolaos G Papadopoulos, Stamatis Gregoriou, Spyridoula Katsarou, Niki Papapostolou et al.
  • Year: 2024
  • Venue: Frontiers in bioscience
  • URL: https://www.semanticscholar.org/paper/4c9790a5cd6a4e9f456e1c65c61b1fe6d8ec96fb
  • DOI: 10.31083/j.fbl2902084
  • PMID: 38420827
  • Citations: 41
  • Influential citations: 2
  • Summary: This review aims to present state-of-the-art knowledge regarding the multifactorial and interactive pathophysiological mechanisms in AD.

[36] Atopic dermatitis: a brief review of recent advances in management

  • Authors: S. Alenazi
  • Year: 2023
  • Venue: Dermatology Reports
  • URL: https://www.semanticscholar.org/paper/d6724d94252a170909214f487ed5af70556c1ce1
  • DOI: 10.4081/dr.2023.9678
  • Citations: 10
  • Summary: This review highlights the recent advancements in the management of AD and identifies new therapeutic strategies designed and developed to target the various steps in the chain of molecular events that lead to the AD phenotype.

[37] Advances in Current Drugs and Formulations for the Management of Atopic Dermatitis.

  • Authors: Keerthi Atluri, S. Manne, V. Nalamothu, A. Mantel, P. Sharma et al.
  • Year: 2023
  • Venue: Critical reviews in therapeutic drug carrier systems
  • URL: https://www.semanticscholar.org/paper/9408f039bc371b4970bf5423ce372aab7baf65f2
  • DOI: 10.1615/critrevtherdrugcarriersyst.2023042979
  • PMID: 37585309
  • Summary: This review scrutinized the use of pharmaceutical inactive ingredients in the approved topical dosage forms for AD treatment and assesses various novel drug delivery strategies currently under clinical investigation.

[38] When Foods Cause Itch: Clinical Characteristics, Pathophysiology, and Recommendations for Food-Induced Skin and Mucosal Pruritus.

  • Authors: A. Vander Does, T. Ju, G. Yosipovitch
  • Year: 2022
  • Venue: Dermatitis : contact, atopic, occupational, drug
  • URL: https://www.semanticscholar.org/paper/fbd3c89943e3fa4f8892f93f8b65ed05547d52be
  • DOI: 10.1097/DER.0000000000000916
  • PMID: 35839419
  • Citations: 2
  • Summary: Although any food seems to have the potential to elicit an immune response, certain foods are especially immunogenic, and careful consideration should be used to avoid unnecessarily restrictive elimination diets.

[39] 1605a Individual susceptibility to work-related contact dermatitis

  • Authors: S. Kežić
  • Year: 2018
  • Venue: Occupational and Environmental Medicine
  • URL: https://www.semanticscholar.org/paper/1cdbb2c1a6012c9cd2038672060701fb7151ba32
  • DOI: 10.1136/oemed-2018-icohabstracts.251
  • Summary: Polymorphisims in several candidate genes responsible for skin barrier, immune response and metabolism showed to play a role in individual susceptibility to contact dermatitis and ACD.

[40] Effects of chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT) on Th2/Th17-related immune modulation in an atopic dermatitis mouse model

  • Authors: Han-Na Go, Seung-Hwa Lee, Hyun‐Ju Cho, Jae-Rin Ahn, M. Kang et al.
  • Year: 2020
  • Venue: Scientific Reports
  • URL: https://www.semanticscholar.org/paper/b01e61ddef1fab17fb64b6501f94429b6e52427d
  • DOI: 10.1038/s41598-020-60966-8
  • PMID: 32139713
  • PMCID: 7058054
  • Citations: 23
  • Summary: The current findings in a mouse model suggest that CMIT/MIT exposure may cause AD symptoms through the dysregulation of Th2/Th17-related immune responses.

[41] Intrinsic Atopic Dermatitis and Extrinsic Atopic Dermatitis: Similarities and Differences

  • Authors: Lu Liu, Guoxuan Song, Zhiqiang Song
  • Year: 2022
  • Venue: Clinical, Cosmetic and Investigational Dermatology
  • URL: https://www.semanticscholar.org/paper/96b040f94b13de9c6be3b11a5a45234f9280e0f4
  • DOI: 10.2147/ccid.s391360
  • Citations: 17
  • Influential citations: 1
  • Summary: Extrinsic AD is the most common type, with high IgE, impaired skin barrier, as well as high incidence of comorbid atopic diseases, whereas intrinsic AD accounted for 20% of AD, with normal IgE and intact barrier function.

[42] Irritant contact dermatitis

  • Authors: I. Ale, H. Maibach
  • Year: 2014
  • Venue: Reviews on Environmental Health
  • URL: https://www.semanticscholar.org/paper/649c2831a2a2a45087b337e2f800e62ff72c6bf5
  • DOI: 10.1515/reveh-2014-0060
  • PMID: 25274939
  • Citations: 54
  • Influential citations: 2
  • Summary: The clinical presentation is highly variable depending on several factors, including properties and strength of the irritant, dose, duration and frequency of exposure, environmental factors, and skin susceptibility.

[43] Allergic Contact Dermatitis in Psoriasis Patients: Typical, Delayed, and Non-Interacting

  • Authors: M. Quaranta, S. Eyerich, Bettina Knapp, F. Nasorri, C. Scarponi et al.
  • Year: 2014
  • Venue: PLoS ONE
  • URL: https://www.semanticscholar.org/paper/804a2085514cf5bd7018df653b9f5133d1d19987
  • DOI: 10.1371/journal.pone.0101814
  • PMID: 25058585
  • PMCID: 4109932
  • Citations: 36
  • Influential citations: 3
  • Summary: It is concluded that sensitized psoriasis patients develop a typical, but delayed ACD reaction which might be relevant for patch test evaluation in clinical practice, indicating that even in clinically non-involved skin of psoriiasis patients molecular events opposing contact dermatitis may occur.

[44] Atopic dermatitis: an expanding therapeutic pipeline for a complex disease

  • Authors: T. Bieber
  • Year: 2021
  • Venue: Nature Reviews Drug Discovery
  • URL: https://www.semanticscholar.org/paper/87e99580bc80578cfffe1e3c391f827ff995b7bf
  • DOI: 10.1038/s41573-021-00266-6
  • Citations: 2
  • Summary: This Review assesses the various strategies and novel agents currently being investigated for AD and highlights the potential for a precision medicine approach to enable prevention and more effective long-term control of this complex disease.

[45] Models of contact dermatitis and atopic eczema

  • Authors: J. Gutermuth, H. Behrendt, J. Ring, T. Jakob
  • Year: 2005
  • Venue: Drug Discovery Today: Disease Models
  • URL: https://www.semanticscholar.org/paper/fa480437691f3b6a87d285c3ee1c8a7165689312
  • DOI: 10.1016/J.DDMOD.2005.05.014
  • Citations: 5
  • Summary: The latest disease models for studying the pathophysiology and treatment modalities, as well as models used for predictive testing of substances with contact sensitizing potential are discussed.

[46] Multiple Roles for Cytokines in Atopic Dermatitis: From Pathogenic Mediators to Endotype-Specific Biomarkers to Therapeutic Targets

  • Authors: L. Fania, G. Moretta, F. Antonelli, E. Scala, D. Abeni et al.
  • Year: 2022
  • Venue: International Journal of Molecular Sciences
  • URL: https://www.semanticscholar.org/paper/90646c04e9fb12f4cc90580ea9b317312acfc13d
  • DOI: 10.3390/ijms23052684
  • PMID: 35269828
  • PMCID: 8910412
  • Citations: 94
  • Influential citations: 3
  • Summary: The role of cytokines in the pathogenesis of AD is discussed, considering patients with various clinical AD phenotypes, and the outcomes of current biologics for AD corroborate the presence of multiple cytokine axes involved in the background of AD.

[47] Microbial–Host Interactions in Dermatologic Inflammation: Ecological, Immunological, and Clinical Perspectives

  • Authors: Carolina Paola Ortiz Valdés, Xóchitl Monteon Aspeitia, Hillary Yahiry Mejía Montiel, Silvana Cabrera Puentes, Claudia Zamaly Ferreira Hernández et al.
  • Year: 2025
  • Venue: International Science Journal
  • URL: https://www.semanticscholar.org/paper/5d064bf684e9703b09ce04e03ff0fba20390b880
  • DOI: 10.64784/050
  • Summary: The evidence underscores the microbiome’s central role in shaping cutaneous inflammation and emphasizes the need for geographically inclusive research and translational innovation to support future dermatologic practice.

[48] Itch in Chronic Wounds: Pathophysiology, Impact, and Management

  • Authors: M. Iannone, A. Janowska, V. Dini, G. Tonini, T. Oranges et al.
  • Year: 2019
  • Venue: Medicines
  • URL: https://www.semanticscholar.org/paper/8ae633c7f4d462cde7e99113a8c7830488e6f90e
  • DOI: 10.3390/medicines6040112
  • PMID: 31731706
  • PMCID: 6963924
  • Citations: 7
  • Summary: Itch in chronic wounds was found to be correlated with xerosis, larger wound areas, necrotic tissue and amount of exudate, peripheral tissue edema, sclerosis, granulation tissue, contact dermatitis, and bacterial burden, as well as with lower quality of life.

[49] New Potential of Roxatidine Acetate Hydrochloride on Atopic Dermatitis Mouse Model, Human Keratinocytes, and Human Skin Equivalent Model

  • Authors: Yun-Mi Kang, Minho Lee, Hyo-Jin An
  • Year: 2021
  • Venue: Frontiers in Pharmacology
  • URL: https://www.semanticscholar.org/paper/ae7a02a1e65a05585ff4b71dbfc8e67545eb3a38
  • DOI: 10.3389/fphar.2021.797086
  • PMID: 35002730
  • PMCID: 8740129
  • Citations: 2
  • Summary: Results showed that RXA treatment significantly alleviated Dfb-induced AD skin symptoms and clinical severity in mice by decreasing the levels of immunoglobulin E, histamine, and inflammatory cytokines and upregulated the expression of aryl hydrocarbon receptor and sirtuin1.

[50] Sebaceous immunobiology - skin homeostasis, pathophysiology, coordination of innate immunity and inflammatory response and disease associations

  • Authors: C. Zouboulis, T. Coenye, Li He, K. Kabashima, Tetsuro Kobayashi et al.
  • Year: 2022
  • Venue: Frontiers in Immunology
  • URL: https://www.semanticscholar.org/paper/b67f52b6d6626f4c279a260ee58e0dd81ebad203
  • DOI: 10.3389/fimmu.2022.1029818
  • PMID: 36439142
  • PMCID: 9686445
  • Citations: 94
  • Influential citations: 2
  • Summary: This review presents several aspects of the innovative concept of sebaceous immunobiology, which summarizes the numerous activities of the sebaceous gland including its classical physiological and pathophysiological tasks, namely sebum production and the development of seborrhea and acne. Sebaceous lipids, which represent 90% of the skin surface lipids in adolescents and adults, are markedly involved in the skin barrier function and perifollicular and dermal innate immune processes, leading t...

[51] Advancing the understanding of allergic contact dermatitis: from pathophysiology to novel therapeutic approaches

  • Authors: M. Tramontana, K. Hansel, L. Bianchi, Chiara Sensini, N. Malatesta et al.
  • Year: 2023
  • Venue: Frontiers in Medicine
  • URL: https://www.semanticscholar.org/paper/1edb98767206171ef69fe0a0df8629b66fb6d56f
  • DOI: 10.3389/fmed.2023.1184289
  • PMID: 37283623
  • PMCID: 10239928
  • Citations: 61
  • Influential citations: 2
  • Summary: Patch testing with suspected allergens is required for a diagnosis of allergic contact dermatitis and metals, especially nickel, fragrance mix, isothiazolinones, and para-phenylenediamine are the most commonly positive allergens in patients patch tested for suspected ACD.
  • Evidence snippets:
  • Snippet 1 (score: 0.575) > Advancing the understanding of allergic contact dermatitis: from pathophysiology to novel therapeutic approaches

[52] Para-Phenylenediamine Sensitization and Polysensitization: TNF-α, CXCL11, and Immune-Regulatory Gene Polymorphisms

  • Authors: Jin Ju Lee, Heera Lee, J. Byun, You Won Choi, J. Roh et al.
  • Year: 2025
  • Venue: Annals of Dermatology
  • URL: https://www.semanticscholar.org/paper/74350d9355d45033fb25fe457a4f8a17f9ab619a
  • DOI: 10.5021/ad.25.102
  • PMID: 41044808
  • PMCID: 12505369
  • Summary: PPD sensitization identifies patients at increased risk for PS and reactivity to mercury compounds and fragrance-related substances and preliminary genetic observations require validation in larger studies to determine potential immunogenetic contributions.
  • Evidence snippets:
  • Snippet 1 (score: 0.502) > Despite genetic analysis limitations, our study advances the understanding of contact allergy pathophysiology by demonstrating that PPD sensitization and PS represent distinct but overlapping immunological phenotypes with characteristic correlation signatures. While preliminary genetic observations require validation in larger studies, the clinical findings regarding PPD-mercury and PPD-fragrance associations, along with the comprehensive PS patterns, provide actionable insights for patch testing strategies and patient counseling.
  • Snippet 2 (score: 0.425) > From the full cohort, a subset of 17 individuals was selected for exploratory genetic analysis using convenience sampling to represent 4 distinct phenotypic groups: (1) PPD+/PS+ (n=7), (2) PPD+/ PS− (n=2), (3) PPD−/PS+ (n=6), and (4) PPD−/PS− (n=2). > Peripheral blood samples were collected for DNA extraction. Five SNPs were selected based on their established roles in contact dermatitis pathophysiology and immune regulation: TNF-α (rs1800629) encodes a key pro-inflammatory cytokine regulating keratinocyte activation and inflammatory responses in ACD 9 ; CXCL11 (rs6817952) encodes an interferon-inducible chemokine crucial for T-cell recruitment and trafficking to allergen exposure sites 13 ; IL-10 (rs1800871) encodes an anti-inflammatory cytokine essential for immune tolerance and inflammation regulation 11 ; IL-16 (rs4778889) encodes a CD4+ T-cell chemoattractant and PPD Sensitization and Polysensitization https://anndermatol.org key mediator in delayed-type hypersensitivity reactions 12 ; and STAT6 (rs1059513) encodes a transcription factor critical for Th2 cell differentiation and allergic immune responses 10 . These polymorphisms represent key nodes in immune pathways relevant to contact sensitization susceptibility. > Statistical analyses were conducted using SPSS version 25.0 (IBM Corp., Armonk, NY, USA) and R version 4.0.3 (R Foundation for Statistical Computing, Vienna, Austria). Intergroup comparisons utilized χ 2 or Fisher's exact test for categorical data, and t-tests or Mann-Whitney U tests for continuous data. Binary logistic regression was performed to evaluate associations between clinical factors and sensitization status, adjusting for potential confounders. For genetic analyses, Fisher's exact test compared genotype frequencies between phenotypic subgroups, with p-values≤0.05 considered statistically significant.
  • Snippet 3 (score: 0.424) > Similarly, the exclusive detection of TNF-α variants in PPD-sensitized patients, while potentially interesting, is based on only 3 patients across all PPD-positive groups and cannot support meaningful conclusions about genetic associations 22,23 . The observed distribution patterns for IL-10, STAT6, and IL-16 polymorphisms across different sensitization phenotypes, though suggestive of potential involvement in immune regulation pathways 24,25 , are similarly limited by small sample sizes and require validation in larger cohorts. Given these limitations, we refrain from detailed mechanistic interpretations of individual polymorphisms and emphasize that our genetic findings represent preliminary observations that may guide future hypothesis-driven research rather than established associations. Nevertheless, the selected polymorphisms represent key nodes in immune pathways relevant to contact dermatitis pathogenesis, and the observed distribution patterns, though requiring validation in larger cohorts, align with the biological functions of these genes in orchestrating immune responses to contact allergens. > Several limitations must be acknowledged. First, the retrospective design and single-center nature of this study may limit the generalizability of findings to other populations with different allergen exposure patterns and genetic backgrounds. Second, the small number of patients who underwent SNP analysis (n=17) significantly limits the generalizability and statistical power of the genetic findings, preventing meaningful statistical comparisons and limiting conclusions about genetic associations. Third, our genetic analysis was limited to 5 selected polymorphisms and may not capture the full spectrum of genetic variants influencing contact sensitization. Fourth, the cross-sectional design prevents assessment of temporal relationships and causality between genetic factors and sensitization development. Fifth, the absence of population-matched genetic controls further limits interpretation of variant frequencies. Finally, longitudinal studies tracking sensitization patterns over time are warranted to determine whether correlation networks evolve or remain stable. Future larger-scale, multi-center studies with comprehensive immunogenetic profiling are essential to validate genetic associations. Adequately powered genetic with population-matched controls are needed to determine whether genetic variants in immune-regulatory pathways contribute to contact sensitization patterns. > Despite genetic analysis limitations, our study advances the understanding of contact allergy pathophysiology by demonstrating that PPD sensitization and PS represent distinct but overlapping immunological phenotypes with characteristic correlation signatures.

[53] Differential diagnosis of contact dermatitis: A practical‐approach review by the EADV Task Force on contact dermatitis

  • Authors: D. Pesqué, O. Aerts, M. Bizjak, M. Gonçalo, Aleksandra Dugonik et al.
  • Year: 2024
  • Venue: Journal of the European Academy of Dermatology and Venereology
  • URL: https://www.semanticscholar.org/paper/1a9753ec7f18a38c01e7a6c3df230cad141a8dc5
  • DOI: 10.1111/jdv.20052
  • PMID: 38713001
  • Citations: 23
  • Influential citations: 1
  • Summary: The Task Force aims to conduct a review of the unifying clinical features of contact dermatitis and characterize its main clinical phenotypes, and its simulators, in order to contribute to an early suspicion or recognition of contact dermatitis and enable a correct differential diagnosis.
  • Evidence snippets:
  • Snippet 1 (score: 0.489) > The diagnosis of eczema (‘dermatitis’) is mostly clinical and depends on the clinical history and exploratory objective findings (primary lesions, patterns). Contact dermatitis remains as an important condition in the group of eczematous disorders, with important socioeconomic and occupational relevance. Although irritant and allergic contact dermatitis have a different pathogenesis, both are characterized by a rather typical morphology, are triggered by external factors and tend to occur primarily in the area of contact with the exogenous agent. In addition, allergic and irritant dermatitis may also co‐exist. The importance of diagnosing contact dermatitis, especially when allergic in nature, is both due to the possibility of avoiding the trigger, and due to its role in aggravating other skin conditions. Nevertheless, the heterogeneity of clinical presentations in daily practice may pose an important challenge for the suspicion and correct diagnosis of contact dermatitis. Furthermore, other conditions, with different pathogenesis and treatment, may clinically simulate contact dermatitis. The Task Force aims to conduct a review of the unifying clinical features of contact dermatitis and characterize its main clinical phenotypes, and its simulators, in order to contribute to an early suspicion or recognition of contact dermatitis and enable a correct differential diagnosis.

[54] Contact dermatitis - Pathomechanism and understanding of disease in clinical setting

  • Authors: M. Mathur, S. Kumari
  • Year: 2012
  • Venue: Journal of College of Medical Sciences-nepal
  • URL: https://www.semanticscholar.org/paper/172b67b28372af01289243e8b13406653928f0b5
  • DOI: 10.3126/JCMSN.V7I4.6816
  • Summary: This review will allow practicing physician to adopt rational clinical approach and the implementation of scientific information for therapeutic as well as preventive strategies.
  • Evidence snippets:
  • Snippet 1 (score: 0.453) > Contact dermatitis - Pathomechanism and understanding of disease in clinical setting

[55] Acetylation Phenotype Variation in Patients with Allergic Contact Dermatitis

  • Authors: R. A. Al-Razzuqi, Abdul-Kareem Naji Al-Kufi, Khansa’ Abdul Ameer Al-Yaser, Yassin Farhan Al-Rekabi
  • Year: 2019
  • Venue: Indian Journal of Dermatology
  • URL: https://www.semanticscholar.org/paper/558dc3dec8e435d7bc27c07d012e30c7036a7588
  • DOI: 10.4103/ijd.IJD_58_17
  • PMID: 30983621
  • PMCID: 6440188
  • Summary: A rapid acetylator status might predispose to ACD without influencing other features of this disease.
  • Evidence snippets:
  • Snippet 1 (score: 0.451) > Acetylation Phenotype Variation in Patients with Allergic Contact Dermatitis

[56] Emerging Links between Microbiome Composition and Skin Immunology in Diaper Dermatitis: A Narrative Review

  • Authors: Tjaša Hertiš Petek, Maya Petek, Tadej Petek, Nataša Marčun Varda
  • Year: 2022
  • Venue: Children
  • URL: https://www.semanticscholar.org/paper/d138abc5a7c67dd84e1e6a63bdab3d0c58cf7140
  • DOI: 10.3390/children9010112
  • PMID: 35053737
  • PMCID: 8775025
  • Citations: 17
  • Influential citations: 1
  • Summary: There is preliminary evidence that certain probiotics given orally or topically could be used as a gentle intervention in diaper dermatitis, suggesting introduction of probiotics is an attractive treatment for microbiome modulation.
  • Evidence snippets:
  • Snippet 1 (score: 0.444) > These results suggest that polymorphisms of individual nucleotides, associated with skin inflammation and homeostasis, can affect responses to irritants and at least partially explain individual differences in the development of contact dermatitis. IL-1α, IL-8 and TNF-α seem to be the most important cytokines in DD [8][9][10][11]42]. Inflammatory processes depend not only on the trigger but also on genetic predispositions [34,35]. However, the exact cytokine profile in DD is still unknown and likely varies between patients, the microbiome composition and the irritant nature.

[57] Cytokines and Chemokines in Irritant Contact Dermatitis

  • Authors: H. Lee, M. Stieger, N. Yawalkar, M. Kakeda
  • Year: 2013
  • Venue: Mediators of Inflammation
  • URL: https://www.semanticscholar.org/paper/5c186b8e8487b573aee2f7e52660a2fbe1d94247
  • DOI: 10.1155/2013/916497
  • PMID: 24371376
  • PMCID: 3858878
  • Citations: 127
  • Influential citations: 8
  • Summary: This review will focus on key cytokines and chemokines involved in the pathogenesis of irritant contact dermatitis and also contrast the differences between allergic contact dermatitus and irritantContact dermatitis.
  • Evidence snippets:
  • Snippet 1 (score: 0.436) > Irritant contact dermatitis (ICD) is an inflammatory response of the skin to various external stimuli. It arises as a result of activated innate immunity to direct injury of the skin without prior sensitization [1][2][3]. ICD is a complex reaction modulated by both intrinsic and extrinsic factors [2][3][4]. Intrinsic factors which influence the susceptibility to ICD include genetic predisposition, for example, atopic diathesis, age, sex, and body region. Extrinsic factors include the inherent nature of the irritants, exposure volume, concentration, duration, repetition, and the presence of further environmental and mechanical factors. > ICD has a spectrum of clinical features which can be divided into several different categories depending on the irritant and its exposure pattern. Ten clinical subtypes have been proposed [2]. The influence of irritants on various cytokines/chemokines has not been well delineated so far, although it is plausible that different environmental insults and the subsequent variation in cytokines/chemokines expression could result in distinct clinical phenotypes. > In this review, we discuss the pathophysiological mechanisms involved in ICD with a focus on key cytokines and chemokines as well as their cellular source in the skin. Furthermore, we highlight the key differences between ICD and allergic contact dermatitis (ACD).

[58] Differential susceptibility between skin and vaginal mucosa in sensitization phase of allergic contact dermatitis in mice

  • Authors: Taku Nishijo, Kanako Nakayama, M. Miyazawa, Y. Kuroda, H. Sakaguchi
  • Year: 2020
  • Venue: Immunity, Inflammation and Disease
  • URL: https://www.semanticscholar.org/paper/06bf6560caf60bd3baabc3a3daf4e299ca3d5d4e
  • DOI: 10.1002/iid3.351
  • PMID: 32914939
  • PMCID: 7654400
  • Citations: 3
  • Summary: Mechanisms underlying skin sensitization in allergic contact dermatitis have been actively studied using the murine contact hypersensitivity (CHS) model, but much less is known about sensitization at the vaginal mucosa.
  • Evidence snippets:
  • Snippet 1 (score: 0.433) > Mechanisms underlying skin sensitization in allergic contact dermatitis have been actively studied using the murine contact hypersensitivity (CHS) model. However, much less is known about sensitization at the vaginal mucosa (VM).

[59] Intricate Relationship Between Adaptive and Innate Immune System in Allergic Contact Dermatitis

  • Authors: M. Azeem, H. Kader, A. Kerstan, H. Hetta, E. Serfling et al.
  • Year: 2020
  • Venue: The Yale Journal of Biology and Medicine
  • URL: https://www.semanticscholar.org/paper/34345717c1dda542d64d9496d28fc675fdb24225
  • PMID: 33380932
  • PMCID: 7757059
  • Citations: 18
  • Influential citations: 1
  • Summary: The main cell types from both immune domains, which are involved in ACD, are focused on, such as CD4+ and CD8+ T cells, B cells, neutrophils, and innate lymphoid cells (ILCs), which can be useful for devising future therapeutic interventions for ACD.
  • Evidence snippets:
  • Snippet 1 (score: 0.412) > Allergic contact dermatitis (ACD) is a complex immunological allergic disease characterized by the interplay between the innate and adaptive immune system. Initially, the role of the innate immune system was believed to be confined to the initial sensitization phase, while adaptive immune reactions were linked with the advanced elicitation phase. However, recent data predicted a comparatively mixed and interdependent role of both immune systems throughout the disease progression. Therefore, the actual mechanisms of disease progression are more complex and interlinked. The aim of this review is to combine such findings that enhanced our understanding of the pathomechanisms of ACD. Here, we focused on the main cell types from both immune domains, which are involved in ACD, such as CD4+ and CD8+ T cells, B cells, neutrophils, and innate lymphoid cells (ILCs). Such insights can be useful for devising future therapeutic interventions for ACD.

[60] MUTZ-3 derived Langerhans cells in human skin equivalents show differential migration and phenotypic plasticity after allergen or irritant exposure.

  • Authors: I. Kosten, S. Spiekstra, T. D. de Gruijl, S. Gibbs
  • Year: 2015
  • Venue: Toxicology and applied pharmacology
  • URL: https://www.semanticscholar.org/paper/016c282bbcebc23731ea72bf3c21de657a8e8ed8
  • DOI: 10.1016/j.taap.2015.05.017
  • PMID: 26028481
  • Citations: 74
  • Influential citations: 2
  • Summary: Mechanisms previously identified as being involved in LC activation and migration in native human skin could thus be reproduced in the in vitro constructed skin equivalent model containing functional LC and will provide a powerful tool for hazard identification, testing novel therapeutics and identifying new drug targets.
  • Evidence snippets:
  • Snippet 1 (score: 0.411) > In this study we provide novel and further evidence that the MUTZ-3 cell line is the most physiologically relevant LC-like cell line identified to date since it shows a unique in vivo like plasticity upon exposure to environmental stimuli (e.g. allergens, irritants). In the past we showed that MUTZ-3 were able to differentiate in a cytokine dependent manner into Langerin expressing LC or, indeed, DC-SIGN expressing dermal DC (Masterson et al., 2002;van de Ven et al., 2011b), which are both able to prime specific T cell responses (Santegoets et al., 2006;Santegoets et al., 2008). Here we show that upon topical allergen exposure epidermal MUTZ-LC mature and migrate in a CXCL12 dependent, and CCL5 independent, manner to the dermal compartment of SE, whereas after topical irritant exposure they migrate in a CCL5 dependent, and CXCL12 independent, manner and undergo an IL-10 dependent phenotypic change to a macrophage-like cell within the dermal compartment. > The SE-LC was designed to enable complex mechanisms concerning human DC biology to be investigated in an animal alternative, physiologically relevant test model. Whereas sensitization after allergen exposure (leading eventually to allergic contact dermatitis (ACD)) has been extensively described in the literature e.g. penetration of chemicals through the stratum corneum, activation of keratinocytes, maturation and migration of LC to the draining lymph nodes and stimulation of T cell responses (Roggen, 2014), extremely little is known about the mechanisms resulting in irritant contact dermatitis (ICD). Clearly, a localized acute inflammatory reaction is involved. Furthermore, it has been shown that the number of CD1a positive cells decreases in both the epidermis and dermis in ICD (Jacobs et al., 2006;Marks et al., 1987). Until now, the fate of these migrated LC was unknown.

[61] Animal Models of Contact Dermatitis

  • Authors: F. Simonetta, C. Bourgeois
  • Year: 2011
  • Venue: Unknown venue
  • URL: https://www.semanticscholar.org/paper/51e0c65da823cb43f6bbb1fd5dab1e08309fcdb8
  • DOI: 10.5772/29462
  • Citations: 5
  • Influential citations: 1
  • Summary: The respective role of innate and adaptive immune cells in contact dermatitis pathogenesis as revealed by murine studies is highlighted and molecular pathways which are promising candidates as targets of future biological therapies are reviewed.
  • Evidence snippets:
  • Snippet 1 (score: 0.402) > Contact dermatitis is an inflammatory disease of the skin resulting from direct contact with foreign substances. Understanding the immunological processes that cause the disease is therefore essential for the development of new therapeutic strategies. Murine models of chemically induced dermatitis have played an essential role in our understanding of the pathophysiology of contact dermatitis, unraveling the role played by inflammatory mediators and identifying potential targets for therapeutic interventions. In the present chapter we review data obtained in animal models of allergic and irritant contact dermatitis and provide basic protocols to reliably induce contact dermatitis. A major intent of this chapter is to highlight the respective role of innate and adaptive immune cells in contact dermatitis pathogenesis as revealed by murine studies. Through genetic ablation of single molecules or depletion of specific cell subsets, murine studies provide novel insight on the role of different components of the immune system in the development of contact dermatitis. We review the experimental evidence revealing the role of different T cell subsets in contact dermatitis development, focusing our attention on mechanisms responsible for maintenance or disruption of immune-tolerance. Our analyses will focus on molecular pathways which are promising candidates as targets of future biological therapies.

[62] Weak Sensitizers May Be Associated with CD80 Polymorphisms: Implications for Systemic Contact Dermatitis

  • Authors: Susan T Nedorost, Ge Zhang, D. Fekedulegn, Kara Fluharty, Wei Wang et al.
  • Year: 2025
  • Venue: JID Innovations
  • URL: https://www.semanticscholar.org/paper/44815e8fb97eb7d3bd2dc6a2fb39054e8bab680b
  • DOI: 10.1016/j.xjidi.2025.100382
  • PMID: 40519868
  • PMCID: 12167014
  • Citations: 2
  • Summary: It was found that positive patch tests to weak allergens were common with 3 polymorphisms of CD80, and ILC2 presentation may bypass education in the local lymph node, explaining the association of antigens classified as non-sensitizers in LLN assay with CD80, and the absence of symptoms of immediate type hypersensitivity in many of these patients.
  • Evidence snippets:
  • Snippet 1 (score: 0.402) > DE is also associated with IgG administration (Voland et al, 2023). > We explored genetic variants important in cutaneous immunology in adult patients with clinically relevant positive patch tests at 2 tertiary, referral contact dermatitis clinics. We stratified patients with a history of early childhood flexural dermatitis as a marker for genetic barrier defects predisposing to chronic irritant dermatitis and patients with a history of DE. > Because innate signals from irritant dermatitis instruct the adaptive response, we also compared our genetic variant associations in this group of patients with ACD with a previously reported cohort of healthcare workers with and without chronic irritant hand dermatitis, analyzed using the same methods (Yucesoy et al, 2016). This allowed us to differentiate genetic variants important in the prerequisite irritant contact dermatitis from those facilitating sensitization to various groups of contact allergens. > Our a priori groupings for allergens on the standard screening series were intended to explore multiple hypotheses at once, including different antigen presentation for metal allergens, immunological differences in antigens metabolized in the skin, differences in polysensitized patients (sensitized to 3 or more chemically unrelated allergens), and differences in patients sensitized to weak antigens. In this study, we explored only the weak allergens (propylene glycol, vanillin, eugenol, and paraben mix); there are many other weak allergens in foods and food additives, but these were chosen because they were included on the standard screening series at both study sites. > We show all the 1450 genetic markers that we explored in the complete dataset (Nedorost et al, 2025). Because of the large number of markers studied, none of the individual analyses survived Bonferroni correction for tests of multiple associations, including the strongest association noted, which was between IL-4R and AD. The latter is well-accepted, and we looked for other associations with similar P-values (P < .005) and ORs (!1.8 or 0.5).

[63] Machine-learning–driven biomarker discovery for the discrimination between allergic and irritant contact dermatitis

  • Authors: V. Fortino, L. Wisgrill, P. Werner, S. Suomela, Nina Linder et al.
  • Year: 2020
  • Venue: Proceedings of the National Academy of Sciences of the United States of America
  • URL: https://www.semanticscholar.org/paper/8cd6f0fb1b6d9cb9edb2e144d4436f98efeb1c9f
  • DOI: 10.1073/pnas.2009192117
  • PMID: 33318199
  • PMCID: 7776829
  • Citations: 64
  • Influential citations: 3
  • Summary: This study identifies and validates biomarkers to distinguish allergic and irritant contact dermatitis in human skin, to be used for the development of novel diagnostic methods and to guide clinical diagnosis of contact allergies.
  • Evidence snippets:
  • Snippet 1 (score: 0.398) > Significance Contact dermatitis is an inflammatory skin disorder that arises from direct skin contact with irritants or allergens. Representing over 90% of occupational skin disorders, it has a considerable socioeconomic impact, and patients suffering from contact dermatitis can develop a notable physical handicap. Current diagnostic regimes rely on allergy testing, exposure specification, and follow-up visits. However, distinguishing the clinical phenotype of irritant and allergic contact dermatitis, which is important for appropriate therapeutic strategies, remains challenging. This study identifies and validates biomarkers to distinguish allergic and irritant contact dermatitis in human skin, to be used for the development of novel diagnostic methods and to guide clinical diagnosis. Contact dermatitis tremendously impacts the quality of life of suffering patients. Currently, diagnostic regimes rely on allergy testing, exposure specification, and follow-up visits; however, distinguishing the clinical phenotype of irritant and allergic contact dermatitis remains challenging. Employing integrative transcriptomic analysis and machine-learning approaches, we aimed to decipher disease-related signature genes to find suitable sets of biomarkers. A total of 89 positive patch-test reaction biopsies against four contact allergens and two irritants were analyzed via microarray. Coexpression network analysis and Random Forest classification were used to discover potential biomarkers and selected biomarker models were validated in an independent patient group. Differential gene-expression analysis identified major gene-expression changes depending on the stimulus. Random Forest classification identified CD47, BATF, FASLG, RGS16, SYNPO, SELE, PTPN7, WARS, PRC1, EXO1, RRM2, PBK, RAD54L, KIFC1, SPC25, PKMYT, HISTH1A, TPX2, DLGAP5, TPX2, CH25H, and IL37 as potential biomarkers to distinguish allergic and irritant contact dermatitis in human skin. Validation experiments and prediction performances on external testing datasets demonstrated potential applicability of the identified biomarker models in the clinic. Capitalizing on this knowledge, novel diagnostic tools can be developed to guide clinical diagnosis of contact allergies.

[64] Immunopathology of allergic contact dermatitis.

  • Authors: L. E. A. M. Martins, V. M. S. Reis
  • Year: 2011
  • Venue: Anais brasileiros de dermatologia
  • URL: https://www.semanticscholar.org/paper/38dfdf2a80098b268dcebc1cca09e974b89bb771
  • DOI: 10.1590/S0365-05962011000300001
  • PMID: 21738956
  • Citations: 28
  • Influential citations: 3
  • Summary: The metabolism and pathway of the haptens as well as the activation and mechanism of action of the cells responsible for both the immune reaction and its completion are discussed in this article.
  • Evidence snippets:
  • Snippet 1 (score: 0.395) > Immunopathology of allergic contact dermatitis.

[65] Transcriptomic Analysis of Allergic Patch Test Reactions in Non‐Atopic Patients: A Comparative Study Across Multiple Allergens

  • Authors: D. Pesqué, Evelyn Andrades, Pau Berenguer-Molins, J. Perera-Bel, Miquel Clarós et al.
  • Year: 2025
  • Venue: Allergy
  • URL: https://www.semanticscholar.org/paper/3b31c17b9eadd782b5ada96175be429b063769a4
  • DOI: 10.1111/all.16642
  • PMID: 40632077
  • PMCID: 12590323
  • Citations: 3
  • Summary: Molecular signatures and their immune mechanisms of different relevant allergens are characterized and their immune mechanisms of different relevant allergens are characterized in strong and extreme positive patch test reactions of patients without atopic dermatitis.
  • Evidence snippets:
  • Snippet 1 (score: 0.388) > Allergic contact dermatitis (ACD) is a common inflammatory condition due to a type IV delayed hypersensitivity response [1]. ACD diagnosis requires performing patch testing, which induces a reaction to the culprit sensitizer [2]. Different animal and human studies have investigated the various mechanisms involved in different phases of ACD. Mechanisms in the sensitization phase have been extensively characterized, whereas immune mechanisms underlying elicitation have yet to be completely elucidated [3]. With respect to elicitation, molecular studies have revealed a double-faceted nature of this condition [4][5][6][7][8]. The presence of common biomarkers and pathways among different allergens in both patch-induced ACD and clinical ACD lesions has been described, with potential application to distinguish ACD from other conditions, including irritant contact dermatitis [4,6]. However, molecular profiling has also shown allergen-dependent immune responses that could contribute to a specific polarization induced by allergen [5]. The number of allergen-specific differentially expressed genes (DEG) may even exceed the number of shared ACD biomarkers [4,5]. > To date, there has been discordance in the immune transcriptomic pathways involved in ACD lesions, particularly in relation to adaptive immune responses [4,5,8]. Several factors, including comorbid skin conditions and reaction severity, may influence the immunological mechanisms in transcriptomic skin studies for ACD. In this regard, atopic dermatitis has been shown to attenuate ACD immune reactions with subsequently altered polarization in patch test studies [9]. Previous studies have demonstrated that more severe patch test reactions may be associated with specific pathologic characteristics [10,11], changes in the phenotype of peripheral blood T cells [12], and detected more dysregulated genes [4].

Notes

  • This provider combines search_papers_by_relevance with snippet_search.
  • No synthesis or second-stage model call is performed.
{ }

Source YAML

click to show 
name: Contact Dermatitis
creation_date: '2026-03-13T18:40:33Z'
updated_date: '2026-03-14T23:13:30Z'
category: Complex
description: >-
  Contact dermatitis is an exogenous inflammatory eczema triggered by direct
  skin exposure to irritants or sensitizing allergens. The umbrella disorder
  includes irritant contact dermatitis, driven by barrier injury and innate
  inflammation, and allergic contact dermatitis, driven by hapten-specific type
  IV T-cell immunity after sensitization.
definitions:
- name: Clinical syndrome definition for contact dermatitis
  definition_type: CASE_DEFINITION
  description: >-
    Contact dermatitis is an exogenous eczematous inflammatory disorder caused
    by direct skin contact with an external substance, most commonly expressed
    as irritant contact dermatitis or allergic contact dermatitis at sites of
    exposure.
  scope: General clinical framing of contact dermatitis in dermatology and occupational medicine
  evidence:
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Contact dermatitis results from skin contact with an exogenous substance."
    explanation: This supports the core disease definition as dermatitis caused by external cutaneous exposure.
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The two most common variants are irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD)."
    explanation: This supports the umbrella disease definition encompassing irritant and allergic forms as the principal variants.
- name: Practical diagnostic definition for suspected allergic contact dermatitis
  definition_type: DIAGNOSTIC_CRITERIA
  description: >-
    In routine practice, suspected allergic contact dermatitis is defined by a
    compatible exposure-linked dermatitis pattern evaluated through focused
    history and physical examination, with patch testing used to confirm
    relevant sensitization and distinguish allergic from irritant disease.
  scope: Clinical diagnosis of recurrent, persistent, or exposure-pattern dermatitis suspicious for allergic contact dermatitis
  evidence:
  - reference: PMID:31757238
    reference_title: "Allergic Contact Dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Diagnosis is based on a thorough history, physical examination, and patch testing."
    explanation: This supports the practical diagnostic framework of history, examination, and patch testing.
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "If ACD is suspected the patient should be referred to secondary care for patch testing."
    explanation: This supports patch testing as the confirmatory step when allergic contact dermatitis is suspected clinically.
synonyms:
- contact dermatitis/eczema
- dermatitis venenata
- contact eczema
disease_term:
  preferred_term: contact dermatitis
  term:
    id: MONDO:0005480
    label: contact dermatitis
mappings:
  icd10cm_mappings:
  - term:
      id: ICD10CM:L23
      label: Allergic contact dermatitis
    mapping_predicate: skos:closeMatch
    mapping_source: ICD-10-CM
    mapping_justification: Contact dermatitis includes allergic contact dermatitis as a major clinical subtype.
  - term:
      id: ICD10CM:L24
      label: Irritant contact dermatitis
    mapping_predicate: skos:closeMatch
    mapping_source: ICD-10-CM
    mapping_justification: Contact dermatitis includes irritant contact dermatitis as a major clinical subtype.
  mondo_mappings:
  - term:
      id: MONDO:0005480
      label: contact dermatitis
    mapping_predicate: skos:exactMatch
    mapping_source: MONDO
    mapping_justification: Primary MONDO disease identifier for this contact dermatitis entry.
classifications:
  harrisons_chapter:
  - classification_value: skin disorder
parents:
- Dermatological Disease
- Inflammatory Disease
has_subtypes:
- name: Allergic Contact Dermatitis
  description: Delayed type IV hypersensitivity dermatitis caused by prior sensitization to a contact allergen.
  evidence:
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Classical ACD is mediated by type 4 cell-mediated immunity."
    explanation: This review explicitly defines allergic contact dermatitis as a type IV cell-mediated immune process.
  - reference: PMID:19839974
    reference_title: "Effector and regulatory mechanisms in allergic contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Allergic contact dermatitis (ACD), one of the commonest occupational diseases, is a T-cell-mediated skin inflammation caused by repeated skin exposure to contact allergens, i.e. nonprotein chemicals called haptens."
    explanation: This supports allergic contact dermatitis as a hapten-driven T-cell-mediated subtype of contact dermatitis.
- name: Irritant Contact Dermatitis
  description: Non-sensitization-dependent dermatitis caused by direct toxic or barrier-disrupting effects of an exposure.
  evidence:
  - reference: PMID:25274939
    reference_title: "Irritant contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Irritant contact dermatitis (ICD) is the most common form of contact dermatitis."
    explanation: This supports irritant contact dermatitis as a principal subtype within the broader contact dermatitis category.
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ICD is a form of eczema and is induced by direct inflammatory pathways without prior sensitisation."
    explanation: This supports the non-sensitization-dependent inflammatory mechanism of irritant contact dermatitis.
pathophysiology:
- name: Irritant exposure and toxic insult
  description: >-
    In irritant contact dermatitis, direct exposure to chemical or physical
    irritants causes the initiating toxic cutaneous insult.
  downstream:
  - target: Epidermal barrier disruption
    description: Toxic or physical irritants injure the epidermis and precipitate barrier failure.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:25274939
      reference_title: "Irritant contact dermatitis."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The pathophysiological mechanism depends on activation of the innate immune system and involves skin barrier disruption"
      explanation: This supports a direct transition from irritant exposure to epidermal barrier injury in irritant contact dermatitis.
  evidence:
  - reference: PMID:25274939
    reference_title: "Irritant contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "It represents the cutaneous response to the toxic/physical effects of a wide variety of environmental agents."
    explanation: This supports direct toxic or physical exposure as the initiating event in irritant contact dermatitis.
- name: Epidermal barrier disruption
  description: >-
    Irritant injury disrupts epidermal barrier integrity and creates the tissue
    context for downstream inflammatory activation.
  cell_types:
  - preferred_term: keratinocyte
    term:
      id: CL:0000312
      label: keratinocyte
  downstream:
  - target: Keratinocyte activation and proinflammatory mediator release
    description: Barrier failure activates keratinocytes and promotes local proinflammatory signaling.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:25274939
      reference_title: "Irritant contact dermatitis."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "involves skin barrier disruption, cellular changes"
      explanation: This supports barrier disruption as the immediate precursor to keratinocyte and mediator activation.
  evidence:
  - reference: PMID:25274939
    reference_title: "Irritant contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "involves skin barrier disruption"
    explanation: This identifies barrier disruption as a distinct mechanistic step in irritant contact dermatitis.
- name: Keratinocyte activation and proinflammatory mediator release
  description: >-
    Barrier-injured keratinocytes enter an activated inflammatory state and
    release mediators that propagate local cutaneous inflammation.
  cell_types:
  - preferred_term: keratinocyte
    term:
      id: CL:0000312
      label: keratinocyte
  biological_processes:
  - preferred_term: keratinocyte activation
    term:
      id: GO:0032980
      label: keratinocyte activation
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
  downstream:
  - target: Innate inflammatory cell recruitment
    description: Keratinocyte-derived inflammatory mediators recruit and activate additional inflammatory cells in skin.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:25274939
      reference_title: "Irritant contact dermatitis."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "release of proinflammatory mediators that directly recruit and activate T lymphocytes."
      explanation: This supports mediator-driven recruitment of inflammatory cells as the next step after keratinocyte activation.
  evidence:
  - reference: PMID:25274939
    reference_title: "Irritant contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "involves skin barrier disruption, cellular changes, and release of proinflammatory mediators."
    explanation: This supports proinflammatory mediator release as a distinct ICD mechanism.
  - reference: DOI:10.1155/2013/916497
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Irritant contact dermatitis is a result of activated innate immune response to various external stimuli and consists of complex interplay which involves skin barrier disruption, cellular changes, and release of proinflammatory mediators."
    explanation: This corroborates activated innate immune signaling and mediator release as central mechanisms in irritant contact dermatitis.
- name: Innate inflammatory cell recruitment
  description: >-
    Irritant-induced mediators recruit and activate inflammatory cells in skin
    after barrier injury.
  cell_types:
  - preferred_term: dendritic cell
    term:
      id: CL:0000451
      label: dendritic cell
  biological_processes:
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
  downstream:
  - target: Contact dermatitis
    description: Inflammatory cell recruitment culminates in the clinically visible dermatitis lesion.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:9590995
      reference_title: "Irritant contact dermatitis. Clues to causes, clinical characteristics, and control."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Clinical signs include vesicles, papules, bullae, erythema, edema, scaling, and lichenification."
      explanation: This supports progression from inflammatory recruitment to clinically evident contact dermatitis.
  evidence:
  - reference: PMID:25274939
    reference_title: "Irritant contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "release of proinflammatory mediators that directly recruit and activate T lymphocytes."
    explanation: This supports recruitment and activation of inflammatory cells as a separate downstream ICD mechanism.
- name: Hapten exposure
  description: >-
    In allergic contact dermatitis, repeated skin contact with small reactive
    chemicals exposes the immune system to haptens and initiates sensitization.
  downstream:
  - target: Skin innate immune activation during sensitization
    description: Hapten exposure activates innate cutaneous immune pathways during the sensitization phase.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:19839974
      reference_title: "Effector and regulatory mechanisms in allergic contact dermatitis."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Recent advances in the pathophysiology of ACD have demonstrated the important role of skin innate immunity in the sensitization process"
      explanation: This supports repeated hapten exposure feeding into innate skin immune activation during sensitization.
  evidence:
  - reference: PMID:19839974
    reference_title: "Effector and regulatory mechanisms in allergic contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Allergic contact dermatitis (ACD), one of the commonest occupational diseases, is a T-cell-mediated skin inflammation caused by repeated skin exposure to contact allergens, i.e. nonprotein chemicals called haptens."
    explanation: This supports hapten exposure as the initiating event in allergic contact dermatitis.
- name: Skin innate immune activation during sensitization
  description: >-
    Early innate immune signaling in allergen-exposed skin shapes the
    sensitization phase and supports subsequent adaptive immune priming.
  cell_types:
  - preferred_term: Langerhans cell
    term:
      id: CL:0000453
      label: Langerhans cell
  - preferred_term: dendritic cell
    term:
      id: CL:0000451
      label: dendritic cell
  downstream:
  - target: Allergen-specific T-cell priming
    description: Innate activation in skin supports dendritic-cell-mediated priming of allergen-specific T cells.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:19839974
      reference_title: "Effector and regulatory mechanisms in allergic contact dermatitis."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Recent advances in the pathophysiology of ACD have demonstrated the important role of skin innate immunity in the sensitization process and have revisited the dogma that Langerhans cells are mandatory for CD8+ T-cell priming."
      explanation: This supports innate skin immune activation as an upstream component of adaptive immune priming in allergic contact dermatitis.
  evidence:
  - reference: PMID:19839974
    reference_title: "Effector and regulatory mechanisms in allergic contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Recent advances in the pathophysiology of ACD have demonstrated the important role of skin innate immunity in the sensitization process"
    explanation: This supports skin innate immune activation as a distinct mechanistic stage in allergic contact dermatitis sensitization.
- name: Breakdown of regulatory T-cell-mediated hapten tolerance
  description: >-
    Allergic contact dermatitis reflects failure of suppressive CD4-positive
    regulatory T-cell programs that normally prevent hapten priming and dampen
    eczema in sensitized individuals.
  cell_types:
  - preferred_term: regulatory T cell
    term:
      id: CL:0000815
      label: regulatory T cell
  downstream:
  - target: Allergen-specific T-cell priming
    description: Loss of regulatory control permits priming to haptens in susceptible individuals.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:19839974
      reference_title: "Effector and regulatory mechanisms in allergic contact dermatitis."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Subsets of CD4+ T cells endowed with suppressive activity are responsible for both the down-regulation of eczema in allergic patients and the prevention of priming to haptens in nonallergic individuals."
      explanation: This supports a direct role for failed regulatory T-cell suppression in permitting allergen-specific T-cell priming.
  - target: Contact dermatitis
    description: Loss of suppressive T-cell control permits persistence and amplification of eczema in allergic patients.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:19839974
      reference_title: "Effector and regulatory mechanisms in allergic contact dermatitis."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Therefore, ACD should be considered as a breakdown of the skin immune tolerance to haptens."
      explanation: This supports failed immune tolerance as a causal contributor to allergic contact dermatitis lesions.
  evidence:
  - reference: PMID:19839974
    reference_title: "Effector and regulatory mechanisms in allergic contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Subsets of CD4+ T cells endowed with suppressive activity are responsible for both the down-regulation of eczema in allergic patients and the prevention of priming to haptens in nonallergic individuals."
    explanation: This review identifies suppressive CD4-positive regulatory T-cell activity as a core counter-regulatory axis in allergic contact dermatitis.
- name: Allergen-specific T-cell priming
  description: >-
    During sensitization, antigen-presenting cells prime allergen-specific T
    cells, establishing the adaptive immune memory required for later flares.
  cell_types:
  - preferred_term: Langerhans cell
    term:
      id: CL:0000453
      label: Langerhans cell
  - preferred_term: dendritic cell
    term:
      id: CL:0000451
      label: dendritic cell
  - preferred_term: CD8-positive, alpha-beta T cell
    term:
      id: CL:0000625
      label: CD8-positive, alpha-beta T cell
  biological_processes:
  - preferred_term: dendritic cell antigen processing and presentation
    term:
      id: GO:0002468
      label: dendritic cell antigen processing and presentation
  - preferred_term: T cell activation
    term:
      id: GO:0042110
      label: T cell activation
  downstream:
  - target: Re-exposure-driven effector T-cell recruitment
    description: Sensitized allergen-specific T cells are recruited back to skin after hapten re-exposure.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:19839974
      reference_title: "Effector and regulatory mechanisms in allergic contact dermatitis."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Allergic contact dermatitis, also referred to as contact hypersensitivity, is mediated by CD8+ T cells, which are primed in lymphoid organs during the sensitization phase and are recruited in the skin upon re-exposure to the hapten."
      explanation: This directly supports progression from sensitization-phase priming to re-exposure-driven effector T-cell recruitment.
  evidence:
  - reference: PMID:19839974
    reference_title: "Effector and regulatory mechanisms in allergic contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Allergic contact dermatitis, also referred to as contact hypersensitivity, is mediated by CD8+ T cells, which are primed in lymphoid organs during the sensitization phase and are recruited in the skin upon re-exposure to the hapten."
    explanation: This supports sensitization and T-cell priming as a discrete adaptive immune stage in allergic contact dermatitis.
- name: Re-exposure-driven effector T-cell recruitment
  description: >-
    Upon renewed hapten exposure, primed effector T cells re-enter skin and
    initiate the elicitation phase of allergic contact dermatitis.
  cell_types:
  - preferred_term: CD8-positive effector T cell
    term:
      id: CL:0000625
      label: CD8-positive, alpha-beta T cell
  biological_processes:
  - preferred_term: type IV hypersensitivity
    term:
      id: GO:0001806
      label: type IV hypersensitivity
  downstream:
  - target: Resident memory T-cell flare activation
    description: Re-exposure activates epidermal resident memory T cells and intensifies the flare response.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:37700557
      reference_title: "CD100 boosts the inflammatory response in the challenge phase of allergic contact dermatitis in mice."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "We show that CD8+ TRM cells express CD100 during homeostatic conditions and up-regulate it following re-exposure of allergen-experienced skin to the experimental contact allergen 1-fluoro-2,4-dinitrobenzene (DNFB)."
      explanation: This supports activation of resident memory T cells after allergen re-exposure during the elicitation phase.
  evidence:
  - reference: PMID:19839974
    reference_title: "Effector and regulatory mechanisms in allergic contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Allergic contact dermatitis, also referred to as contact hypersensitivity, is mediated by CD8+ T cells, which are primed in lymphoid organs during the sensitization phase and are recruited in the skin upon re-exposure to the hapten."
    explanation: This supports effector T-cell recruitment to skin on hapten re-exposure as a separate mechanism node.
- name: Resident memory T-cell flare activation
  description: >-
    Epidermal resident memory CD8-positive T cells are activated in
    allergen-experienced skin and intensify local flare responses.
  cell_types:
  - preferred_term: resident memory CD8-positive T cell
    term:
      id: CL:0000625
      label: CD8-positive, alpha-beta T cell
  downstream:
  - target: Mixed type 1 and type 3 cytokine and chemokine amplification
    description: Activated resident memory T cells drive a broader inflammatory cytokine and chemokine program.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:37700557
      reference_title: "CD100 boosts the inflammatory response in the challenge phase of allergic contact dermatitis in mice."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "We show that loss of CD100 results in a reduced inflammatory response to DNFB with impaired production of IFNγ, IL-17A, CXCL1, CXCL2, CXCL5, and IL-1β and decreased recruitment of neutrophils to the epidermis."
      explanation: This supports resident memory T-cell-dependent amplification of cytokine and chemokine production during allergic flare responses.
  evidence:
  - reference: PMID:37700557
    reference_title: "CD100 boosts the inflammatory response in the challenge phase of allergic contact dermatitis in mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "BACKGROUND: Allergic contact dermatitis (ACD) is an inflammatory disease with a complex pathophysiology in which epidermal-resident memory CD8+ T (TRM ) cells play a key role."
    explanation: This supports resident memory CD8-positive T cells as a distinct driver of allergic contact dermatitis flares.
- name: Mixed type 1 and type 3 cytokine and chemokine amplification
  description: >-
    Activated effector and resident memory T cells amplify IFNg-, IL-17A-,
    IL-1beta-, and chemokine-rich inflammatory programs, with predominant type
    1 and type 3 effector responses and lesser type 2 contributions.
  cell_types:
  - preferred_term: T cell
    term:
      id: CL:0000084
      label: T cell
  - preferred_term: neutrophil
    term:
      id: CL:0000775
      label: neutrophil
  biological_processes:
  - preferred_term: chemokine production
    term:
      id: GO:0032602
      label: chemokine production
  downstream:
  - target: Fibroblast CXCL9/CXCL10 reinforcement
    description: Type 1 lymphocyte-derived IFNg reprograms dermal fibroblasts into chemokine-producing inflammatory stromal cells.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:39213029
      reference_title: "Defining cell type-specific immune responses in a mouse model of allergic contact dermatitis by single-cell transcriptomics."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "IFNγ treatment shifted dermal fibroblasts from collagen-producing to CXCL9/10-producing, which promoted T cell polarization toward the type-1 phenotype through a CXCR3-dependent mechanism."
      explanation: This supports a direct edge from type 1 inflammatory cytokine signaling to fibroblast chemokine reinforcement.
  evidence:
  - reference: PMID:37700557
    reference_title: "CD100 boosts the inflammatory response in the challenge phase of allergic contact dermatitis in mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "We show that loss of CD100 results in a reduced inflammatory response to DNFB with impaired production of IFNγ, IL-17A, CXCL1, CXCL2, CXCL5, and IL-1β and decreased recruitment of neutrophils to the epidermis."
    explanation: This supports amplification of inflammatory cytokines, chemokines, and neutrophil recruitment as a discrete downstream mechanism in allergic contact dermatitis.
  - reference: DOI:10.1111/all.16642
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "All allergens exhibited mixed effector immune responses, mainly type 1 and 3 immunity, and, to a lesser extent, type 2 immunity."
    explanation: This human transcriptomic study supports mixed type 1 and type 3 cytokine programs, with lesser type 2 contributions, during allergic contact dermatitis elicitation.
- name: Fibroblast CXCL9/CXCL10 reinforcement
  description: >-
    Dermal fibroblasts adopt a chemokine-producing inflammatory phenotype that
    reinforces type 1 lymphocyte polarization and sustains cutaneous
    inflammation.
  cell_types:
  - preferred_term: fibroblast
    term:
      id: CL:0000057
      label: fibroblast
  - preferred_term: T cell
    term:
      id: CL:0000084
      label: T cell
  biological_processes:
  - preferred_term: chemokine production
    term:
      id: GO:0032602
      label: chemokine production
  downstream:
  - target: Contact dermatitis
    description: Fibroblast chemokine reinforcement sustains the inflammatory dermatitis lesion in affected skin.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:39213029
      reference_title: "Defining cell type-specific immune responses in a mouse model of allergic contact dermatitis by single-cell transcriptomics."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "Together, our results define the cell type-specific immune responses in ACD, and recognize an indispensable role of dermal fibroblasts in shaping the development of type-1 skin inflammation through the IFNGR-CXCR3 signaling circuit during ACD pathogenesis."
      explanation: This supports fibroblast chemokine reinforcement as a direct contributor to sustained allergic contact dermatitis lesions.
  evidence:
  - reference: PMID:39213029
    reference_title: "Defining cell type-specific immune responses in a mouse model of allergic contact dermatitis by single-cell transcriptomics."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "IFNγ treatment shifted dermal fibroblasts from collagen-producing to CXCL9/10-producing, which promoted T cell polarization toward the type-1 phenotype through a CXCR3-dependent mechanism."
    explanation: This supports inflammatory fibroblast reprogramming as a distinct amplifying mechanism in allergic contact dermatitis.
- name: Complement-associated sensory neuron activation
  description: >-
    In allergic contact dermatitis, complement-associated neuroimmune signaling
    activates peripheral sensory pathways and contributes to itch generation.
  cell_types:
  - preferred_term: sensory neuron
    term:
      id: CL:0000101
      label: sensory neuron
  downstream:
  - target: Pruritus
    description: Sensory neuron activation contributes to the itching phenotype in allergic contact dermatitis.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:34417985
      reference_title: "Proteome Profile of Trigeminal Ganglion in Murine Model of Allergic Contact Dermatitis: Complement 3 Pathway Contributes to Itch and Pain Sensation."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "The complement system in sensory ganglion might play an essential role in forming pruritic and nociceptive sensations in ACD."
      explanation: This supports complement-associated sensory neuron activation as a direct contributor to pruritus in allergic contact dermatitis.
  evidence:
  - reference: PMID:34417985
    reference_title: "Proteome Profile of Trigeminal Ganglion in Murine Model of Allergic Contact Dermatitis: Complement 3 Pathway Contributes to Itch and Pain Sensation."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "The complement system in sensory ganglion might play an essential role in forming pruritic and nociceptive sensations in ACD."
    explanation: This supports complement-linked sensory pathway activation as a distinct neuroimmune mechanism in allergic contact dermatitis.
phenotypes:
- name: Contact dermatitis
  category: Dermatological
  diagnostic: true
  frequency: OBLIGATE
  notes: Localized eczematous inflammation at sites of irritant or allergen exposure.
  phenotype_term:
    preferred_term: Contact dermatitis
    term:
      id: HP:0032282
      label: Contact dermatitis
  evidence:
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The two most common variants are irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD)."
    explanation: This supports the broad clinical entity of contact dermatitis comprising allergic and irritant forms.
- name: Pruritus
  category: Dermatological
  diagnostic: true
  frequency: FREQUENT
  notes: Itching is a common symptom, especially in allergic forms and on thin skin sites such as the eyelids.
  phenotype_term:
    preferred_term: Pruritus
    term:
      id: HP:0000989
      label: Pruritus
  evidence:
  - reference: PMID:39941494
    reference_title: "Eyelid Contact Dermatitis: 25-Year Single-Center Retrospective Study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Background/Objectives: Eyelid dermatitis is an inflammatory disease affecting the palpebral skin characterized by itching, edema, and scaling of the periorbital area."
    explanation: This human clinical series supports itching as a characteristic manifestation of contact dermatitis.
- name: Erythema
  category: Dermatological
  frequency: FREQUENT
  notes: Erythematous patches or plaques are common at exposed or directly contacted skin sites.
  phenotype_term:
    preferred_term: Erythema
    term:
      id: HP:0010783
      label: Erythema
  evidence:
  - reference: PMID:9590995
    reference_title: "Irritant contact dermatitis. Clues to causes, clinical characteristics, and control."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Clinical signs include vesicles, papules, bullae, erythema, edema, scaling, and lichenification."
    explanation: This review supports erythema as a common clinical sign of contact dermatitis, particularly irritant presentations.
- name: Scaling skin
  category: Dermatological
  frequency: FREQUENT
  notes: Scaling commonly accompanies eczematous plaques and chronic hand or eyelid dermatitis.
  phenotype_term:
    preferred_term: Scaling skin
    term:
      id: HP:0040189
      label: Scaling skin
  evidence:
  - reference: PMID:39941494
    reference_title: "Eyelid Contact Dermatitis: 25-Year Single-Center Retrospective Study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Background/Objectives: Eyelid dermatitis is an inflammatory disease affecting the palpebral skin characterized by itching, edema, and scaling of the periorbital area."
    explanation: This human clinical study supports scaling as a characteristic manifestation of contact dermatitis.
histopathology:
- name: Spongiotic dermatitis pattern
  description: >-
    Allergic contact dermatitis falls within the broader histopathologic pattern
    of spongiotic or eczematous dermatitis, so biopsy findings require
    clinicopathologic correlation and exposure assessment rather than stand
    alone as a definitive discriminator.
  subtype: Allergic Contact Dermatitis
  evidence:
  - reference: PMID:39709083
    reference_title: "Epidermal spongiotic Langerhans cell collections, but not eosinophils, are a clue to the diagnosis of allergic contact dermatitis: A series of 170 clinically- and patch test-confirmed cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "BACKGROUND: Allergic contact dermatitis cannot be reliably differentiated from other forms of spongiotic/eczematous dermatitis by histology alone."
    explanation: This supports spongiotic/eczematous dermatitis as the core histopathologic pattern of allergic contact dermatitis while emphasizing its limited specificity.
- name: Epidermal spongiotic Langerhans cell collections
  description: >-
    Within allergic contact dermatitis biopsies, epidermal collections of
    Langerhans cells are a supportive microscopic clue that can favor the
    diagnosis over other spongiotic dermatoses.
  subtype: Allergic Contact Dermatitis
  evidence:
  - reference: PMID:39709083
    reference_title: "Epidermal spongiotic Langerhans cell collections, but not eosinophils, are a clue to the diagnosis of allergic contact dermatitis: A series of 170 clinically- and patch test-confirmed cases."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "CONCLUSION: This largest study to date is the first to independently confirm Langerhans cell collections as the single histopathologic feature most closely associated with allergic contact dermatitis."
    explanation: This supports epidermal spongiotic Langerhans cell collections as a biopsy feature that favors allergic contact dermatitis.
prevalence:
- population: Adults from five European countries
  percentage: 15.0
  notes: >-
    Questionnaire-based lifetime occurrence estimate in a representative
    cross-sectional sample of adults aged 18-74 years from Germany, Italy, the
    Netherlands, Portugal, and Sweden. A related European population study of
    contact allergy reported a nearly identical age-standardized lifetime
    contact dermatitis estimate of 15.1%.
  evidence:
  - reference: PMID:29247509
    reference_title: "Prevalence of skin disease in a population-based sample of adults from five European countries."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The most common skin disease was warts (41·3%), followed by acne (19·2%) and contact dermatitis (15·0%)."
    explanation: This provides a direct population-based lifetime prevalence estimate for contact dermatitis in adults from five European countries.
  - reference: PMID:26370659
    reference_title: "Prevalence of contact allergy in the general population in different European regions."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Subjects reporting contact dermatitis in their lifetime (age-standardized prevalence 15·1%, 95% CI 13·8-16·3)"
    explanation: This independent European population study closely replicates the approximately 15% lifetime contact dermatitis prevalence estimate.
- population: General population over a lifetime
  percentage: 15.0
  notes: >-
    Approximate lifetime burden cited in a U.S. population-based epidemiology
    study background; consistent with the directly measured European
    population-based estimates above, but not itself a pooled global
    meta-analytic prevalence estimate.
  evidence:
  - reference: PMID:39403761
    reference_title: "Contact Dermatitis in the United States: A Population-Based Study on Patient Visit Characteristics and Treatment Prescription Patterns."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Background: Contact dermatitis (CD) affects ∼15% of the general population over a lifetime."
    explanation: This U.S. population-based study cites an approximately 15% lifetime general-population burden, supporting the broader prevalence context.
epidemiology:
- name: Predominant occupational skin disease burden
  description: Contact dermatitis is the dominant occupational skin disorder and accounts for most cases of occupational skin disease in industrialized settings.
  factors:
  - occupation
  evidence:
  - reference: PMID:19580930
    reference_title: "Management of occupational dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Contact dermatitis is the most common occupational skin disorder, responsible for up to 30% of all cases of occupational disease in industrialized nations."
    explanation: This review supports contact dermatitis as a leading occupational disease burden.
  - reference: PMID:19580930
    reference_title: "Management of occupational dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Epidemiologic data suggest that contact dermatitis accounts for 90% to 95% of all cases of occupational skin disease"
    explanation: This review supports contact dermatitis as the major contributor to occupational skin disease cases.
genetic:
- name: FLG loss-of-function variants and allergic sensitization susceptibility
  association: Risk Factor
  subtype: Allergic Contact Dermatitis
  notes: Barrier-impaired filaggrin deficiency increases penetrance of contact allergens and raises the risk of sensitization in people with dermatitis.
  gene_term:
    preferred_term: FLG
    term:
      id: hgnc:3748
      label: FLG
  evidence:
  - reference: PMID:23343419
    reference_title: "Filaggrin mutations are strongly associated with contact sensitization in individuals with dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "FLG mutation carriers with self-reported dermatitis have an increased risk of contact sensitization to substances other than nickel"
    explanation: This human population study supports FLG loss-of-function variants as a genetic risk factor for contact sensitization relevant to allergic contact dermatitis.
- name: FLG loss-of-function variants and irritant contact dermatitis susceptibility
  association: Risk Factor
  subtype: Irritant Contact Dermatitis
  notes: Filaggrin deficiency contributes to barrier vulnerability and independently increases occupational irritant contact dermatitis risk.
  gene_term:
    preferred_term: FLG
    term:
      id: hgnc:3748
      label: FLG
  evidence:
  - reference: PMID:23039796
    reference_title: "Impact of atopic dermatitis and loss-of-function mutations in the filaggrin gene on the development of occupational irritant contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Our results indicate that both FLG mutations and AD increase the risk of ICD."
    explanation: This occupational case-control study supports FLG variants as an independent genetic susceptibility factor for irritant contact dermatitis.
environmental:
- name: Wet work and detergent exposure
  exposure_term:
    preferred_term: exposure to detergent
    term:
      id: ECTO:9001690
      label: exposure to detergent
    qualifiers:
    - predicate:
        preferred_term: has participant
        term:
          id: RO:0000057
          label: has participant
      value:
        preferred_term: skin of manus
        term:
          id: UBERON:0001519
          label: skin of manus
  description: >-
    Repetitive wet work and exposure to soaps and detergents are common
    environmental drivers of irritant contact dermatitis, especially on the
    hands.
  effect: TRIGGERS
  evidence:
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Cumulative effects of water, soaps and detergents are the most common cause of ICD which affects the hands more often than any other site."
    explanation: This supports wet work and detergent exposure as major environmental triggers of irritant contact dermatitis.
- name: Nickel exposure
  exposure_term:
    preferred_term: exposure to nickel
    term:
      id: ECTO:9000063
      label: exposure to nickel
  description: >-
    Exposure to nickel-containing jewelry, tools, and occupational metal
    sources is a common environmental trigger of allergic contact dermatitis.
  effect: TRIGGERS
  evidence:
  - reference: DOI:10.3389/fmed.2023.1184289
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Metals, especially nickel, fragrance mix, isothiazolinones, and para-phenylenediamine, are the most commonly positive allergens in patients patch tested for suspected ACD."
    explanation: This review identifies nickel as one of the most common sensitizing exposures in allergic contact dermatitis.
- name: Fragrance exposure
  exposure_term:
    preferred_term: exposure to fragrance
    term:
      id: ECTO:9001808
      label: exposure to fragrance
  description: >-
    Fragrance-containing cosmetics, personal care products, and topical agents
    are common environmental triggers of allergic contact dermatitis.
  effect: TRIGGERS
  evidence:
  - reference: DOI:10.3389/fmed.2023.1184289
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Metals, especially nickel, fragrance mix, isothiazolinones, and para-phenylenediamine, are the most commonly positive allergens in patients patch tested for suspected ACD."
    explanation: This review identifies fragrance mix as a common sensitizer in patients patch tested for allergic contact dermatitis.
- name: Isothiazolinone exposure
  description: >-
    Exposure to isothiazolinone preservatives in personal care, household, and
    industrial products is a recognized environmental trigger of allergic
    contact dermatitis.
  effect: TRIGGERS
  evidence:
  - reference: DOI:10.3389/fmed.2023.1184289
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Metals, especially nickel, fragrance mix, isothiazolinones, and para-phenylenediamine, are the most commonly positive allergens in patients patch tested for suspected ACD."
    explanation: This review identifies isothiazolinones as common sensitizing preservatives in allergic contact dermatitis.
  - reference: PMID:41804652
    reference_title: "Prevalence of Contact Allergy to Isothiazolinones in Dermatitis Patients From 2000 to 2025: A Systematic Review and Meta-Analysis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The prevalence of CA to methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) was 4.58%, methylisothiazolinone (MI) was 5.48%, and benzisothiazolinone (BIT) was 2.09%."
    explanation: This meta-analysis adds current human prevalence data showing multiple isothiazolinone preservatives are established sensitizers among dermatitis patients.
- name: Mastisol adhesive exposure
  exposure_term:
    preferred_term: exposure to glue
    term:
      id: ECTO:7000130
      label: exposure to glue
  description: >-
    Exposure to Mastisol liquid adhesive used for wound closure is a reported
    trigger of allergic contact dermatitis after surgical procedures.
  effect: TRIGGERS
  evidence:
  - reference: PMID:30465037
    reference_title: "Allergic Contact Dermatitis to Mastisol Adhesive Used for Skin Closure in Orthopedic Surgery: A Case Report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We report on a rare case of allergic contact dermatitis (ACD) from Mastisol liquid adhesive."
    explanation: This case report supports Mastisol as a specific adhesive trigger of allergic contact dermatitis.
- name: 2-octyl cyanoacrylate adhesive exposure
  exposure_term:
    preferred_term: exposure to glue
    term:
      id: ECTO:7000130
      label: exposure to glue
    qualifiers:
    - predicate:
        preferred_term: has input
        term:
          id: RO:0002233
          label: has input
      value:
        preferred_term: acrylate
        term:
          id: CHEBI:37080
          label: acrylate
  description: >-
    Exposure to 2-octyl cyanoacrylate topical skin adhesives used for surgical
    wound closure is an increasingly recognized trigger of allergic contact
    dermatitis, especially after repeat exposure.
  effect: TRIGGERS
  evidence:
  - reference: PMID:41784277
    reference_title: "Systematic Review and Meta Analysis of Allergic Contact Dermatitis from 2-Octyl Cyanoacrylate Adhesives."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "2-octyl cyanoacrylate (2-OCA) topical skin adhesives are widely used for surgical wound closure but are increasingly associated with allergic contact dermatitis (ACD)."
    explanation: This systematic review supports 2-octyl cyanoacrylate as a specific surgical adhesive trigger of allergic contact dermatitis.
  - reference: PMID:41784277
    reference_title: "Systematic Review and Meta Analysis of Allergic Contact Dermatitis from 2-Octyl Cyanoacrylate Adhesives."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Re-exposure markedly increased risk, with reaction rates rising from 1-3% after initial exposure to >20% in staged or repeat procedures in several cohorts."
    explanation: This supports repeat exposure as an important risk amplifier for cyanoacrylate-triggered allergic contact dermatitis.
- name: Para-phenylenediamine exposure
  description: >-
    Exposure to para-phenylenediamine, particularly in hair dyes and related
    products, is a common environmental trigger of allergic contact dermatitis.
  effect: TRIGGERS
  evidence:
  - reference: DOI:10.3389/fmed.2023.1184289
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Metals, especially nickel, fragrance mix, isothiazolinones, and para-phenylenediamine, are the most commonly positive allergens in patients patch tested for suspected ACD."
    explanation: This review identifies para-phenylenediamine as a common sensitizer in allergic contact dermatitis.
- name: Rubber accelerator exposure
  description: >-
    Exposure to rubber accelerators in gloves, footwear, and occupational
    materials is a common environmental trigger of allergic contact dermatitis.
  effect: TRIGGERS
  evidence:
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Nickel, fragrances, rubber accelerators and biocides are the most common sensitisers in ACD."
    explanation: This review identifies rubber accelerators as common sensitizers in allergic contact dermatitis.
- name: Biocide exposure
  description: >-
    Exposure to biocides and preservative chemicals in occupational and consumer
    products is a common environmental trigger of allergic contact dermatitis.
  effect: TRIGGERS
  evidence:
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Nickel, fragrances, rubber accelerators and biocides are the most common sensitisers in ACD."
    explanation: This review identifies biocides as common sensitizers in allergic contact dermatitis.
- name: Repeated and high-concentration allergen exposure
  description: >-
    Repeated contact and higher local concentrations of potential allergens
    increase the probability of sensitization and later allergic flares.
  effect: Increases sensitization risk
  evidence:
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Frequent exposure and high concentrations of potential allergens increase the risk of sensitisation."
    explanation: This supports repeated or intense exposure as an environmental risk factor for allergic sensitization.
- name: Toxicodendron exposure
  exposure_term:
    preferred_term: exposure to allergen
    term:
      id: ECTO:0000726
      label: exposure to allergen
    qualifiers:
    - predicate:
        preferred_term: has input
        term:
          id: RO:0002233
          label: has input
      value:
        preferred_term: urushiol III
        term:
          id: CHEBI:9909
          label: urushiol III
  description: >-
    Exposure to Toxicodendron plants such as poison ivy, poison oak, and poison
    sumac is a common environmental trigger of allergic contact dermatitis.
  effect: TRIGGERS
  evidence:
  - reference: PMID:14700441
    reference_title: "Topical pimecrolimus in the treatment of human allergic contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Plants of the Toxicodendron species cause allergic contact dermatitis (ACD) in 50% to 70% of the population."
    explanation: This supports Toxicodendron plant exposure as a common and clinically important trigger of allergic contact dermatitis.
  - reference: PMID:27548435
    reference_title: "CD1a on Langerhans cells controls inflammatory skin disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Among various urushiol congeners, we identified diunsaturated pentadecylcatechol (C15:2) as the dominant antigen for CD1a-restricted T cells."
    explanation: This supports urushiol III, the diunsaturated pentadecylcatechol congener, as a specific Toxicodendron allergen linked to poison ivy dermatitis.
- name: Lime and other psoralen-rich citrus exposure with ultraviolet light
  description: >-
    Contact with lime juice or peel followed by ultraviolet exposure can trigger
    phytophotodermatitis, a phototoxic contact reaction that may be mistaken for
    allergic dermatitis.
  effect: TRIGGERS
  evidence:
  - reference: PMID:41064302
    reference_title: "Mojito-Induced Phytophotodermatitis: A Case of Lime-Triggered Skin Reaction."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lime-induced phytophotodermatitis, sometimes called \"lime disease\" or \"margarita photodermatitis,\" is one of the most common forms, caused by furocoumarins in lime juice or peel."
    explanation: This case report supports lime-derived psoralen exposure with UV light as a specific trigger of photocontact dermatitis.
- name: Mare's milk soap exposure
  description: >-
    Soap products containing mare's milk have been reported as specific triggers
    of allergic contact dermatitis in sensitized individuals.
  effect: TRIGGERS
  evidence:
  - reference: PMID:40921440
    reference_title: "Allergic Contact Dermatitis Triggered by a Mare's Milk-Based Soap."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Allergic Contact Dermatitis Triggered by a Mare's Milk-Based Soap."
    explanation: The report title directly identifies mare's milk-based soap as a documented trigger of allergic contact dermatitis.
treatments:
- name: Allergen and irritant avoidance
  description: >-
    Identification and avoidance of the offending allergen or irritant is the
    central management strategy for both allergic and irritant contact
    dermatitis.
  treatment_term:
    preferred_term: medical action avoidance
    term:
      id: MAXO:0001014
      label: medical action avoidance
  evidence:
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Accurate diagnosis, avoidance of identified allergens and protection from irritants are the key to successful treatment."
    explanation: This supports avoidance of sensitizers and irritants as first-line disease management.
  - reference: PMID:9590995
    reference_title: "Irritant contact dermatitis. Clues to causes, clinical characteristics, and control."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Elimination of the offending agent and protection from further exposure are important in both diagnosis and management."
    explanation: This independently supports exposure elimination and barrier protection as core treatment measures.
- name: Topical corticosteroids
  description: >-
    Topical corticosteroids are used to treat inflammatory flares, especially in
    allergic contact dermatitis, while avoidance remains essential for long-term
    control.
  treatment_term:
    preferred_term: topical corticosteroid therapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
    qualifiers:
    - predicate:
        preferred_term: therapeutic agent
        term:
          id: NCIT:C2259
          label: Therapeutic Agent
      value:
        preferred_term: therapeutic corticosteroid
        term:
          id: NCIT:C211
          label: Therapeutic Corticosteroid
    - predicate:
        preferred_term: route of administration
        term:
          id: NCIT:C38114
          label: Route of Administration
      value:
        preferred_term: topical route of administration
        term:
          id: NCIT:C38304
          label: Topical Route of Administration
  evidence:
  - reference: PMID:31757238
    reference_title: "Allergic Contact Dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Topical corticosteroids can be used to treat exacerbations, but should be avoided in long-term treatment."
    explanation: This supports topical corticosteroids for short-term treatment of inflammatory exacerbations.
- name: Topical calcineurin inhibitors
  description: >-
    Topical calcineurin inhibitors can be used as steroid-sparing topical
    therapy in selected allergic contact dermatitis settings, although evidence
    is mixed across allergens and agents. Tacrolimus improved chronic
    nickel-induced allergic contact dermatitis in a randomized trial, whereas
    pimecrolimus was ineffective for established Toxicodendron-induced allergic
    contact dermatitis in a small placebo-controlled study.
  treatment_term:
    preferred_term: topical calcineurin inhibitor therapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
    qualifiers:
    - predicate:
        preferred_term: therapeutic agent
        term:
          id: NCIT:C2259
          label: Therapeutic Agent
      value:
        preferred_term: tacrolimus
        term:
          id: CHEBI:61049
          label: tacrolimus (anhydrous)
    - predicate:
        preferred_term: therapeutic agent
        term:
          id: NCIT:C2259
          label: Therapeutic Agent
      value:
        preferred_term: pimecrolimus
        term:
          id: CHEBI:135888
          label: pimecrolimus
    - predicate:
        preferred_term: route of administration
        term:
          id: NCIT:C38114
          label: Route of Administration
      value:
        preferred_term: topical route of administration
        term:
          id: NCIT:C38304
          label: Topical Route of Administration
  evidence:
  - reference: PMID:16781290
    reference_title: "A prospective randomized clinical trial of 0.1% tacrolimus ointment in a model of chronic allergic contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "CONCLUSIONS: Tacrolimus ointment 0.1% is well tolerated and significantly more effective than vehicle in treating chronically exposed, nickel-induced ACD."
    explanation: This randomized clinical trial supports topical tacrolimus as an effective steroid-sparing option for chronic nickel-induced allergic contact dermatitis.
  - reference: PMID:14700441
    reference_title: "Topical pimecrolimus in the treatment of human allergic contact dermatitis."
    supports: REFUTE
    evidence_source: HUMAN_CLINICAL
    snippet: "CONCLUSIONS: The application of topical pimecrolimus is ineffective in the treatment of ongoing Toxicodendron-induced ACD."
    explanation: This placebo-controlled human study refutes efficacy of pimecrolimus for established Toxicodendron-induced allergic contact dermatitis.
- name: Systemic corticosteroids
  description: >-
    Systemic corticosteroids are used for more severe or widespread flares of
    allergic contact dermatitis when topical treatment alone is insufficient,
    while culprit avoidance remains the core intervention.
  treatment_term:
    preferred_term: pharmacotherapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
    qualifiers:
    - predicate:
        preferred_term: therapeutic agent
        term:
          id: NCIT:C2259
          label: Therapeutic Agent
      value:
        preferred_term: therapeutic corticosteroid
        term:
          id: NCIT:C211
          label: Therapeutic Corticosteroid
  evidence:
  - reference: DOI:10.3389/fmed.2023.1184289
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The treatment goal is to avoid contact with the culprit agent and use topical and/or systemic corticosteroid therapy."
    explanation: This review supports systemic corticosteroid therapy as a treatment option for allergic contact dermatitis alongside trigger avoidance.
diagnosis:
- name: Exposure history and lesion-pattern assessment
  description: >-
    Diagnosis begins with careful review of exposures, timing, occupational and
    personal products, and the anatomic distribution of dermatitis.
  diagnosis_term:
    preferred_term: clinical history and physical examination
    term:
      id: MAXO:0000003
      label: diagnostic procedure
  evidence:
  - reference: PMID:31757238
    reference_title: "Allergic Contact Dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Diagnosis is based on a thorough history, physical examination, and patch testing."
    explanation: This supports exposure-focused clinical history and examination as the foundation of diagnosis.
  - reference: DOI:10.1073/pnas.2009192117
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Current diagnostic regimes rely on allergy testing, exposure specification, and follow-up visits."
    explanation: This supports exposure specification and serial clinical assessment as standard parts of the diagnostic workflow for contact dermatitis.
- name: Patch testing for suspected allergic contact dermatitis
  description: >-
    Patch testing is used when allergic contact dermatitis is suspected,
    especially in recurrent or persistent disease, to identify relevant
    sensitizers and distinguish allergic from irritant dermatitis; common
    positive allergens include metals, fragrance mixes, isothiazolinones, and
    para-phenylenediamine.
  diagnosis_term:
    preferred_term: patch testing
    term:
      id: MAXO:0000003
      label: diagnostic procedure
    qualifiers:
    - predicate:
        preferred_term: has participant
        term:
          id: RO:0000057
          label: has participant
      value:
        preferred_term: skin of body
        term:
          id: UBERON:0002097
          label: skin of body
  evidence:
  - reference: PMID:31757238
    reference_title: "Allergic Contact Dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Diagnosis is based on a thorough history, physical examination, and patch testing."
    explanation: This supports patch testing as a core diagnostic modality for allergic contact dermatitis.
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "If ACD is suspected the patient should be referred to secondary care for patch testing."
    explanation: This supports referral for patch testing when allergic contact dermatitis is clinically suspected.
  - reference: DOI:10.3389/fmed.2023.1184289
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Patch testing with suspected allergens is required for a diagnosis."
    explanation: This review reinforces patch testing as the defining diagnostic procedure for allergic contact dermatitis.
differential_diagnoses:
- name: Atopic dermatitis
  disease_term:
    preferred_term: atopic dermatitis
    term:
      id: MONDO:0004980
      label: atopic eczema
  description: >-
    Atopic dermatitis can overlap with contact dermatitis when patients present
    with chronic pruritic eczema, and the two disorders may coexist in the same
    patient.
  distinguishing_features:
  - Atopic dermatitis more often shows a chronic relapsing endogenous eczema pattern with broader flexural involvement and an atopic background.
  - Contact dermatitis is more tightly linked to external exposures and tends to localize to the area of contact with the exogenous trigger.
  evidence:
  - reference: PMID:38713001
    reference_title: "Differential diagnosis of contact dermatitis: A practical-approach review by the EADV Task Force on contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Furthermore, other conditions, with different pathogenesis and treatment, may clinically simulate contact dermatitis."
    explanation: This task-force review supports atopic dermatitis as part of the clinical differential diagnosis for contact dermatitis.
  - reference: PMID:38713001
    reference_title: "Differential diagnosis of contact dermatitis: A practical-approach review by the EADV Task Force on contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Although irritant and allergic contact dermatitis have a different pathogenesis, both are characterized by a rather typical morphology, are triggered by external factors and tend to occur primarily in the area of contact with the exogenous agent."
    explanation: This supports exposure-linked localization as a key feature that helps distinguish contact dermatitis from broader endogenous eczema such as atopic dermatitis.
- name: Psoriasis
  disease_term:
    preferred_term: psoriasis
    term:
      id: MONDO:0005083
      label: psoriasis
  description: >-
    Psoriasis can mimic chronic scaly dermatitis, especially on the hands or
    scalp, but it is a distinct immune-mediated papulosquamous disorder rather
    than an exposure-driven eczema.
  distinguishing_features:
  - Psoriasis more often produces sharply demarcated plaques with thick adherent scale and characteristic extensor, scalp, or nail involvement.
  - Contact dermatitis is usually linked to a relevant irritant or allergen exposure history and improves when the offending exposure is removed.
  evidence:
  - reference: PMID:38713001
    reference_title: "Differential diagnosis of contact dermatitis: A practical-approach review by the EADV Task Force on contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Furthermore, other conditions, with different pathogenesis and treatment, may clinically simulate contact dermatitis."
    explanation: This practical review supports psoriasis as a plausible simulator within the differential diagnosis of contact dermatitis.
  - reference: PMID:25102574
    reference_title: "Identifying the causes of contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Contact dermatitis results from skin contact with an exogenous substance."
    explanation: This supports exogenous exposure as a distinguishing feature of contact dermatitis relative to psoriasis.
- name: Tinea corporis
  disease_term:
    preferred_term: tinea corporis
    term:
      id: MONDO:0001461
      label: tinea corporis
  description: >-
    Dermatophyte infection can resemble localized eczematous dermatitis when
    lesions are annular and scaly, particularly if exposure history is unclear.
  distinguishing_features:
  - Tinea corporis typically shows an annular advancing border with central clearing and is confirmed by fungal testing when needed.
  - Contact dermatitis is evaluated through exposure history and, for allergic disease, patch testing rather than mycologic testing.
  evidence:
  - reference: PMID:38713001
    reference_title: "Differential diagnosis of contact dermatitis: A practical-approach review by the EADV Task Force on contact dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Furthermore, other conditions, with different pathogenesis and treatment, may clinically simulate contact dermatitis."
    explanation: This supports superficial fungal infection as part of the broader mimic set that must be separated from contact dermatitis.
  - reference: PMID:31757238
    reference_title: "Allergic Contact Dermatitis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Diagnosis is based on a thorough history, physical examination, and patch testing."
    explanation: This supports patch testing and exposure-based evaluation as distinguishing elements for allergic contact dermatitis.
clinical_trials:
- name: NCT05535738
  phase: PHASE_II
  status: RECRUITING
  description: >-
    Recruiting combined phase 2/3 mechanistic interventional study using a
    controlled contact dermatitis model with biologic pretreatment and suction
    blister-based skin sampling to dissect cutaneous inflammatory pathways.
  target_phenotypes:
  - preferred_term: Contact dermatitis
    term:
      id: HP:0032282
      label: Contact dermatitis
  evidence:
  - reference: clinicaltrials:NCT05535738
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The purpose of this study is to answer: how do inflammation and anti-inflammatory skin therapies work in the skin?"
    explanation: This official study record supports a currently recruiting interventional trial that uses a contact dermatitis model to study inflammatory skin responses.
  notes: ClinicalTrials.gov lists this as a combined phase 2/3 study; mapped to PHASE_II because the schema accepts a single phase value.
- name: NCT02778711
  phase: PHASE_III
  status: UNKNOWN
  description: >-
    Registered phase 3 interventional study evaluating secukinumab as a
    targeted treatment strategy for severe allergic contact dermatitis.
  target_phenotypes:
  - preferred_term: Pruritus
    term:
      id: HP:0000989
      label: Pruritus
  - preferred_term: Erythema
    term:
      id: HP:0010783
      label: Erythema
  evidence:
  - reference: clinicaltrials:NCT02778711
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The purpose of this study is to assess the efficacy of anti-IL 17 treatment (secukinumab) in patients with known severe allergic contact dermatitis (ACD)."
    explanation: This official study record supports a registered interventional trial directly focused on severe allergic contact dermatitis.
datasets:
- accession: GEO:GSE153007
  title: Genome-Wide Profiling of Lesional and Non-Lesional Skin from Atopic Dermatitis, Psoriasis, and Contact Dermatitis Skin
  description: >-
    Comparative human skin transcriptomic dataset spanning lesional and
    non-lesional samples from contact dermatitis alongside atopic dermatitis and
    psoriasis, enabling cross-disease comparison of inflammatory programs.
  organism:
    preferred_term: Homo sapiens
    term:
      id: NCBITaxon:9606
      label: Homo sapiens
  data_type: MICROARRAY
  conditions:
  - contact dermatitis skin
  - non-lesional skin
  - atopic dermatitis skin
  - psoriasis skin
  evidence:
  - reference: GEO:GSE153007
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Genome-Wide Profiling of Lesional and Non-Lesional Skin from Atopic Dermatitis, Psoriasis, and Contact Dermatitis Skin"
    explanation: This GEO record supports a disease-relevant comparative skin transcriptomic dataset that explicitly includes contact dermatitis samples.
  notes: "Dataset record: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE153007"
- accession: GEO:GSE215457
  title: Inhibition of DYRK1B suppresses inflammation in allergic contact dermatitis model and Th1/Th17 immune response
  description: >-
    Transcriptomic dataset associated with DYRK1B inhibition experiments used to
    interrogate T-cell inflammatory programs relevant to allergic contact
    dermatitis and Th1/Th17 polarization.
  organism:
    preferred_term: Homo sapiens
    term:
      id: NCBITaxon:9606
      label: Homo sapiens
  data_type: BULK_RNA_SEQ
  evidence:
  - reference: GEO:GSE215457
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "To investigate the inhibition effect of DYRK1B kinase function on human naïve CD4+ T cell differetionation which stimulated under Treg polarizing condition for 24 hours."
    explanation: This GEO record supports a human T-cell transcriptomic dataset tied to mechanistic allergic contact dermatitis work on inflammatory T-cell polarization.
  notes: "Dataset record: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE215457"
references:
- reference: PMID:19839974
  title: Effector and regulatory mechanisms in allergic contact dermatitis.
  findings: []
- reference: PMID:25102574
  title: Identifying the causes of contact dermatitis.
  findings: []
- reference: PMID:25274939
  title: Irritant contact dermatitis.
  findings: []
- reference: PMID:31757238
  title: Allergic Contact Dermatitis.
  findings: []
- reference: PMID:38713001
  title: "Differential diagnosis of contact dermatitis: A practical-approach review by the EADV Task Force on contact dermatitis."
  findings: []
- reference: PMID:39709083
  title: "Epidermal spongiotic Langerhans cell collections, but not eosinophils, are a clue to the diagnosis of allergic contact dermatitis: A series of 170 clinically- and patch test-confirmed cases."
  findings: []
- reference: PMID:26370659
  title: Prevalence of contact allergy in the general population in different European regions.
  findings: []
- reference: PMID:23343419
  title: Filaggrin mutations are strongly associated with contact sensitization in individuals with dermatitis.
  findings: []
- reference: PMID:23039796
  title: Impact of atopic dermatitis and loss-of-function mutations in the filaggrin gene on the development of occupational irritant contact dermatitis.
  findings: []
- reference: PMID:19580930
  title: Management of occupational dermatitis.
  findings: []
- reference: PMID:30465037
  title: "Allergic Contact Dermatitis to Mastisol Adhesive Used for Skin Closure in Orthopedic Surgery: A Case Report."
  findings: []
- reference: PMID:41804652
  title: "Prevalence of Contact Allergy to Isothiazolinones in Dermatitis Patients From 2000 to 2025: A Systematic Review and Meta-Analysis."
  findings: []
- reference: PMID:41784277
  title: Systematic Review and Meta Analysis of Allergic Contact Dermatitis from 2-Octyl Cyanoacrylate Adhesives.
  findings: []
- reference: PMID:41064302
  title: "Mojito-Induced Phytophotodermatitis: A Case of Lime-Triggered Skin Reaction."
  findings: []
- reference: PMID:40921440
  title: "Allergic Contact Dermatitis Triggered by a Mare's Milk-Based Soap."
  findings: []
- reference: DOI:10.1073/pnas.2009192117
  title: Machine-learning–driven biomarker discovery for the discrimination between allergic and irritant contact dermatitis
  findings: []
- reference: DOI:10.1155/2013/916497
  title: Cytokines and Chemokines in Irritant Contact Dermatitis
  findings: []
- reference: DOI:10.3389/fmed.2023.1184289
  title: "Advancing the understanding of allergic contact dermatitis: from pathophysiology to novel therapeutic approaches"
  findings: []
- reference: DOI:10.1111/all.16642
  title: "Transcriptomic Analysis of Allergic Patch Test Reactions in Non‐Atopic Patients: A Comparative Study Across Multiple Allergens"
  findings: []