⚙

Pathophysiology

7

Dietary Protein Allergen Exposure

Ingestion of an intact or partially digested food protein presents that protein to the gut mucosal immune system. A small number of foods account for the great majority of IgE-mediated disease, which is one reason allergen identity rather than diet composition in general is the exposure that matters.

Downstream

Oligomeric Allergen Epitope Display The ingested protein reaches the mucosa as an assembled particle, so its native quaternary structure determines how many IgE epitopes are presented together.

Show evidence (1 reference)

PMID:38349368 SUPPORT Human clinical

"In the US, 9 foods account for more than 90% of IgE-mediated food allergies-crustacean shellfish, dairy, peanut, tree nuts, fin fish, egg, wheat, soy, and sesame."

Establishes that a small set of food proteins dominates IgE-mediated food allergy.

Oligomeric Allergen Epitope Display

Many major food allergens are not monomers. Native Ara h 1, the peanut 7S vicilin, assembles into higher-order homo-oligomers (nonamer or decamer), and a truncated 54 kDa isoform lacking the N-terminal domain is instead exclusively trimeric -- which localises the higher-order oligomerisation interface to that N-terminal domain. The cow's milk whey lipocalin beta-lactoglobulin (Bos d 5) likewise associates into dimers in solution. Because oligomerisation multiplies the copies of an epitope carried on one particle, this quaternary structure sets the valency available for downstream FcepsilonRI crosslinking, and the oligomerisation interface is therefore a structural determinant of effector potency rather than an incidental biophysical property. The epitopes must also be *accessible*: in beta-lactoglobulin, occupancy of the lipocalin ligand pocket is predicted to mask major IgE and T-cell epitopes, so the same protein displays different epitope surfaces in its ligand-free and ligand-loaded states.

allergen homo-oligomerisation GO:0051260

Downstream

Failure of Oral Tolerance Induction Ligand-free beta-lactoglobulin presents unmasked IgE and T-cell epitopes and behaves as an allergen, whereas the ligand-loaded form supports a tolerogenic outcome.

Multivalent FcepsilonRI Crosslinking An oligomeric allergen presents two or more spatially arranged IgE epitopes on one particle, which is the minimum requirement for productive receptor crosslinking.

Show evidence (3 references)

PMID:33439436 SUPPORT DIRECT In vitro / ex vivo

"We found that 63 kDa Ara h 1 occurs as higher order homo-oligomeric conformations such as decamer or nonamer, while 54 kDa Ara h 1 occurs exclusively as a homotrimer, indicating that the N-terminal domain of the 63 kDa molecule may be involved in higher order oligomerization."

Establishes both the oligomeric state of a major peanut allergen and the location of the interface driving higher-order assembly, by contrasting the full-length protein with an N-terminally truncated isoform.

PMID:30923869 SUPPORT DIRECT In vitro / ex vivo

"it was shown that β-lg forms dimeric structures in 50 mM HEPES buffer under various conditions of the medium"

Small-angle scattering evidence that beta-lactoglobulin self-associates into dimers, giving a second, non-legume example of an oligomeric food allergen.

PMID:32485264 SUPPORT INDIRECT Computational

"Modeling predicted masking of major IgE and T-cell epitopes of BLG by ligand binding."

Docking and modelling result predicting that ligand occupancy of the beta-lactoglobulin pocket occludes its major IgE and T-cell epitopes, so epitope accessibility is state-dependent. Graded COMPUTATIONAL and INDIRECT because the quoted claim is a prediction; the experimental confirmation is cited separately on the tolerance node.

Failure of Oral Tolerance Induction

The default response to a dietary protein is peripheral tolerance, in which a specialised RORgt- and PRDM16-dependent lineage of intestinal antigen-presenting cells drives antigen-specific peripherally induced regulatory T cells. Food allergy begins when this programme is not engaged for a given protein and the response is instead primed toward type 2 immunity. The beta-lactoglobulin ligand-state experiments show that the same protein can take either route: loaded holo-beta-lactoglobulin prevented sensitisation while sustaining regulatory T cells, whereas the ligand-free apo form acted as an allergen -- a demonstration that tolerance versus sensitisation can be decided by the allergen's own loading state rather than by its sequence.

tolerogenic RORgt+ PRDM16+ intestinal antigen-presenting cell CL:0000145 peripherally induced regulatory T cell CL:0000815

oral tolerance induction to dietary protein GO:0002507 ↓ DECREASED

Downstream

Type 2 Immune Reprogramming With the tolerogenic programme not engaged, the allergen-specific response is primed toward type 2 immunity instead.

Show evidence (3 references)

PMID:41328802 SUPPORT REVIEW SYNTHESIS Other

"Recent studies have revealed that intestinal antigen-specific pTreg cell differentiation is induced by a distinct lineage of antigen-presenting cells (APCs) requiring expression of the transcription factors RORγt and PRDM16."

Identifies the antigen-presenting cell lineage and transcription factors required for peripheral tolerance to dietary antigens, which is the programme whose failure this node describes. Graded OTHER with REVIEW_SYNTHESIS because the quoted sentence is a review's synthesis of work it did not perform.

PMID:32485264 SUPPORT DIRECT Model organism

"In mice, only treatments with holoBLG prevented allergic sensitization and anaphylaxis, while sustaining regulatory T cells."

In vivo demonstration that the ligand-loaded state of beta-lactoglobulin prevents sensitisation and maintains regulatory T cells, supporting the tolerance arm of this node.

PMID:32485264 SUPPORT INDIRECT Model organism

"Our data provide a mechanistic explanation why the same proteins can act either as tolerogens or as allergens."

The authors' own statement of the general principle this node encodes: tolerance versus sensitisation is not fixed by the protein's identity alone.

Type 2 Immune Reprogramming

The allergen-specific CD4 T cell response is redirected toward a T-helper 2 programme, with group 2 innate lymphoid cells contributing innate type 2 cytokine production. IL-4 and IL-13 from this compartment are the signals that license the B cell switch to IgE, making this the step at which a tolerogenic response is converted into a sensitising one.

allergen-specific T-helper 2 cell CL:0000546 group 2 innate lymphoid cell CL:0001069

type 2 immune response to dietary allergen GO:0042092 ↑ INCREASED T-helper 2 cell differentiation GO:0045064 ↑ INCREASED

Downstream

IgE Class Switching and FcepsilonRI Arming Type 2 cytokines, principally IL-4 and IL-13, drive the immunoglobulin heavy-chain switch to IgE in allergen-specific B cells.

IgE Class Switching and FcepsilonRI Arming

Allergen-specific B cells switch to the IgE isotype and differentiate into IgE-secreting plasma cells. Secreted IgE binds the high-affinity receptor FcepsilonRI on tissue mast cells and circulating basophils, arming them for an allergen-specific response. Sensitisation is clinically silent at this point; the disease becomes manifest only on re-exposure, which is why anaphylaxis is not expected on a genuinely first exposure.

IgE-secreting plasma cell CL:0000947

isotype switching to IgE GO:0048289 ↑ INCREASED

Downstream

Multivalent FcepsilonRI Crosslinking Receptor-bound allergen-specific IgE is the substrate that an incoming multivalent allergen crosslinks.

Show evidence (2 references)

PMID:41715900 SUPPORT REVIEW SYNTHESIS Other

"CD4+ cells, especially Tfh, play a fundamental role in the sequential class switching of memory B cells in germinal centers to convert them into IgE‐producing cells."

Supports the dependence of the IgE class switch on CD4 T cell help, linking the type 2 node upstream to IgE production at this node. Graded OTHER with REVIEW_SYNTHESIS because the quoted sentence is a review's synthesis rather than its own experimental result.

PMID:41715900 SUPPORT REVIEW SYNTHESIS Other

"Chronic allergen exposure promotes the accumulation of long‐lived IgE plasma cells in the bone marrow, thereby sustaining enduring serological memory and contributing to the persistence of allergic disease"

Accounts for why sensitisation persists once established, which is the reason avoidance rather than clearance of IgE is the mainstay of management.

Multivalent FcepsilonRI Crosslinking

An allergen bearing two or more IgE epitopes bridges adjacent IgE-FcepsilonRI complexes, and the resulting receptor aggregate initiates signalling. Valency and epitope spacing are not merely permissive: tetravalent antigen produces larger, more complex aggregates and stronger responses than bivalent antigen, can signal at low IgE occupancy, and the geometry of the aggregate determines signalling efficiency. This is the step at which the oligomeric state of the allergen is converted into a quantitative difference in effector output.

mast cell CL:0000097 basophil CL:0000767

Fc-epsilon receptor signaling pathway GO:0038095 ↑ INCREASED

Downstream

Mast Cell and Basophil Degranulation Aggregated FcepsilonRI signals through Lyn and Syk to calcium mobilisation and granule exocytosis, with aggregate geometry setting the efficiency of that coupling.

Show evidence (2 references)

PMID:42589421 SUPPORT INDIRECT In vitro / ex vivo

"Thus, allergen valency and epitope spatial arrangement dictate FcεRI aggregate organization and subsequent effector cell activation."

Primary conclusion that allergen valency and epitope arrangement control receptor aggregate organisation and effector activation. Graded INDIRECT because the valency series was built from a grass-pollen (Phl p 1) epitope grafted onto a myoglobin scaffold rather than from a food allergen, so the principle transfers by inference.

PMID:42589421 SUPPORT DIRECT BACKGROUND In vitro / ex vivo

"It has been well established that at least two IgE epitopes are required on an allergen to induce effector cell degranulation, and that increases in valency trigger even stronger responses"

States the established minimum-valency requirement that makes allergen oligomerisation mechanistically load-bearing. Marked BACKGROUND because the sentence sits in this paper's introduction and restates work it cites rather than its own result.

Mast Cell and Basophil Degranulation

FcepsilonRI signalling triggers calcium influx and exocytosis of preformed granule contents, principally histamine and tryptase, together with newly generated lipid mediators. This is the effector event that produces the clinical reaction, and it is the step whose systemic consequences epinephrine is given to reverse. Serum tryptase released here is also the diagnostic marker of an anaphylactic event.

mucosal mast cell CL:0000485 basophil CL:0000767

mast cell degranulation GO:0043303 ↑ INCREASED IgE-mediated histamine secretion GO:0097279 ↑ INCREASED

Downstream

Urticaria Histamine-driven dermal vasodilatation and wheal formation.

Angioedema Mediator-driven deep dermal and submucosal extravasation.

Vomiting Gastrointestinal mediator release on mucosal allergen contact.

Wheezing Mediator-driven bronchial smooth muscle constriction.

Hypotension Systemic mediator release causes vasodilatation and capillary leak, the circulatory failure of anaphylaxis.

Food-induced anaphylaxis Simultaneous multi-system mediator effects constitute the anaphylactic syndrome.

Show evidence (2 references)

PMID:42589421 SUPPORT INDIRECT In vitro / ex vivo

"Tetravalent MB4N evoked stronger degranulation and Ca2+ response than bivalent antigens MB1N1C and MB2N."

Measures degranulation and calcium response as a function of antigen valency, linking allergen multivalency quantitatively to this node's output. INDIRECT because the antigen series is a scaffold construct rather than a food allergen.

PMID:32485264 SUPPORT DIRECT Human clinical

"In line with this modeling, IgE binding in children allergic to milk was reduced toward holoBLG, which also impaired degranulation of mast cells."

Shows with sera from milk-allergic children that reducing accessible IgE epitopes on beta-lactoglobulin reduces IgE binding and impairs mast cell degranulation, connecting epitope display to this effector node in human material.

⬡

Pathograph

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Phenotypes

6

Cardiovascular 3

Urticaria HP:0001025

Temporal: ACUTE

Angioedema HP:0100665

Temporal: ACUTE

Hypotension HP:0002615

Temporal: ACUTE

Digestive 1

Vomiting HP:0002013

Temporal: ACUTE

Immune 1

Food-induced anaphylaxis HP:0500095

Temporal: ACUTE

Show evidence (1 reference)

PMID:38349368 SUPPORT Human clinical

"IgE-mediated food allergies may cause anaphylaxis and death."

Establishes anaphylaxis and death as outcomes of IgE-mediated food allergy.

Respiratory 1

Wheezing HP:0030828

Temporal: ACUTE

🧬

Genetic Associations

4

FLG (Associated)

Gene: FLG hgnc:3748 gene page relationship_type: RISK_FACTOR

Show evidence (2 references)

PMID:29051540 SUPPORT PRIMARY RESULT Human clinical

"We identify five loci at genome-wide significance, the clade B serpin (SERPINB) gene cluster at 18q21.3, the cytokine gene cluster at 5q31.1, the filaggrin gene, the C11orf30/LRRC32 locus, and the human leukocyte antigen (HLA) region."

Names the filaggrin gene among the five genome-wide significant food-allergy loci.

PMID:39698764 SUPPORT REVIEW SYNTHESIS Human clinical

"Identified genes for food allergy are mainly involved in epithelial barrier function (e.g., FLG, SERPINB7) and immune function (e.g., HLA, IL4)."

Review grouping FLG under the epithelial-barrier arm of food-allergy genetic risk.

SERPINB10 (Associated)

Gene: SERPINB10 hgnc:8942 relationship_type: RISK_FACTOR

Show evidence (1 reference)

PMID:29051540 SUPPORT PRIMARY RESULT Human clinical

"Variants in the SERPINB gene cluster are associated with SERPINB10 expression in leukocytes."

Localises the 18q21.3 food-allergy association to SERPINB10 expression.

IL4 (Associated)

Gene: IL4 hgnc:6014 gene page relationship_type: RISK_FACTOR

Show evidence (1 reference)

PMID:39698764 SUPPORT REVIEW SYNTHESIS Human clinical

"Identified genes for food allergy are mainly involved in epithelial barrier function (e.g., FLG, SERPINB7) and immune function (e.g., HLA, IL4)."

Names IL4 as the immune-function arm of food-allergy genetic risk.

EMSY (Associated)

Gene: EMSY hgnc:18071 gene page relationship_type: RISK_FACTOR

Show evidence (1 reference)

PMID:29030101 SUPPORT PRIMARY RESULT Human clinical

"This study identifies multiple novel loci as risk factors for PA and food allergy and establishes C11orf30 as a risk locus for both PA and food allergy."

Establishes C11orf30/EMSY as a genome-wide significant food-allergy risk locus.

💊

Medical Actions

4

Culprit Allergen Avoidance

Action: allergen elimination diet Ontology label: Allergen Elimination Diet NCIT:C219792

Platform: Behavioral / lifestyle

Strict dietary exclusion of the identified allergen. This remains the cornerstone of management and the only intervention that prevents reactions rather than treating them.

Mechanism Target:

Dietary Protein Allergen Exposure — Avoidance acts at the exposure node, removing the antigen that would otherwise reach armed effector cells.

Show evidence (1 reference)

PMID:38349368 SUPPORT Human clinical

"The cornerstone of IgE-food allergy management is avoidance of the culprit food allergen."

States allergen avoidance as the cornerstone of management.

Epinephrine

Action: Pharmacotherapy NCIT:C15986

Agent: epinephrine CHEBI:33568

Platform: Small molecule

Prompt intramuscular epinephrine, usually by self-injectable autoinjector, is the first-line treatment for food-related anaphylaxis. It does not act on the allergic mechanism upstream of degranulation; it opposes the systemic consequences of mediator release through alpha-1-mediated vasoconstriction and beta-2-mediated bronchodilation.

Mechanism Target:

Hypotension — Alpha-1 adrenergic vasoconstriction reverses the vasodilatation and capillary leak produced by systemic mediator release.

Wheezing — Beta-2 adrenergic bronchodilation opposes mediator-driven bronchospasm.

Show evidence (1 reference)

PMID:38349368 SUPPORT Human clinical

"Self-injectable epinephrine is the first-line treatment for food-related anaphylaxis."

Establishes epinephrine as first-line treatment for food-related anaphylaxis.

Peanut Oral Immunotherapy (AR101)

Action: oral immunotherapy Ontology label: Immunotherapy NCIT:C15262

Platform: Other

Escalating-dose oral immunotherapy with a characterised peanut protein product, FDA-approved for peanut allergy. It raises the dose tolerated at challenge and reduces symptom severity on exposure, but it is an adjunct to avoidance and epinephrine rather than a replacement: it desensitises rather than curing, and patients continue to carry epinephrine.

Mechanism Target:

Multivalent FcepsilonRI Crosslinking — Desensitisation raises the allergen dose required to produce a reaction, acting on the threshold at which effector crosslinking becomes clinically significant.

Show evidence (1 reference)

PMID:30449234 SUPPORT Human clinical

"AR101 resulted in higher doses of peanut protein that could be ingested without dose-limiting symptoms and in lower symptom severity during peanut exposure at the exit food challenge than placebo."

Phase 3 randomised trial result establishing the desensitising effect and its limits.

Omalizumab

Action: Pharmacotherapy NCIT:C15986

Agent: omalizumab NCIT:C29299

Platform: Monoclonal antibody

Omalizumab is an anti-IgE monoclonal antibody, FDA-approved for reducing allergic reactions to foods in patients with one or more food allergies. It sequesters free IgE so that less is available to arm FcepsilonRI on mast cells and basophils, raising the reaction threshold across multiple foods at once. Like oral immunotherapy it raises the threshold rather than curing, and patients continue to avoid the culprit foods and carry epinephrine.

Mechanism Target:

IgE Class Switching and FcepsilonRI Arming — By binding free IgE, omalizumab lowers the pool available to arm FcepsilonRI, acting on the arming step upstream of crosslinking.

Show evidence (1 reference)

PMID:38407394 SUPPORT Human clinical

"A total of 79 of the 118 participants (67%) receiving omalizumab met the primary end-point criteria, as compared with 4 of the 59 participants (7%) receiving placebo (P<0.001)."

OUtMATCH phase 3 randomised result: omalizumab monotherapy raised the peanut reaction threshold far more than placebo, the trial behind the FDA approval.

🌍

Environmental Factors

2

Early oral introduction of allergenic food

Introducing an allergenic food by mouth during infancy, rather than delaying it, engages oral tolerance and prevents allergy. In LEAP the protection persisted to age 12, and a pooled LEAP+EAT analysis showed a 75% reduction in peanut allergy; the benefit shrinks the later introduction is delayed, which is the opposite of the predisposing exposure on the skin arm below.

Show evidence (2 references)

PMID:36435990 SUPPORT Human clinical

"An intention-to-treat (ITT) analysis of pooled data showed a 75% reduction in PA (p < .0001) among children randomized to consume peanut from early infancy."

Pooled LEAP+EAT randomised data quantifying the protective effect of early oral introduction.

PMID:36521802 SUPPORT Human clinical

"The preventive benefit of early introduction of peanut products into the diet decreases as age at introduction increases."

Establishes the age-dependent window over which the protective effect operates.

Mechanism Target:

PROTECTS_AGAINST Failure of Oral Tolerance Induction — Early oral exposure drives the peripheral-tolerance programme for the food protein, so this node's failure is averted rather than triggered.

Show evidence (1 reference)

PMID:38804779 SUPPORT Human clinical

"peanut allergy remained significantly more prevalent in participants in the original peanut avoidance group than in the original peanut consumption group"

LEAP follow-up to age 12: oral peanut from infancy roughly a third of the allergy rate of avoidance, supporting oral exposure acting on the tolerance node.

Cutaneous allergen exposure through an impaired skin barrier

The dual-allergen-exposure hypothesis holds that encountering a food allergen across inflamed or barrier-impaired skin (as in atopic dermatitis) primes sensitisation, while the same allergen taken orally promotes tolerance. The outcome is context-dependent: healthy skin promotes tolerance, and only about a third of children with atopic dermatitis go on to a food allergy, so this is a predisposing route rather than a sufficient cause.

Show evidence (1 reference)

PMID:41967460 SUPPORT REVIEW SYNTHESIS Human clinical

"The dual-allergen exposure hypothesis suggests that impaired skin barrier exposure leads to sensitization, whereas early oral intake induces tolerance."

Review statement of the dual-allergen-exposure hypothesis grounding this exposure.

Mechanism Target:

PREDISPOSES Type 2 Immune Reprogramming — Cutaneous exposure on inflamed skin routes the allergen-specific response toward type 2 priming instead of tolerance, predisposing to the reprogramming node.

Show evidence (1 reference)

PMID:38740132 SUPPORT Human clinical

"The dual allergen exposure hypothesis posits that sensitization to food allergens may occur with cutaneous exposure on inflamed skin, eg, atopic dermatitis, but early oral consumption generally leads to tolerance."

States the cutaneous-sensitisation versus oral-tolerance contrast this link encodes.

🔬

Diagnosis

4

Skin prick testing

A skin prick test detects IgE sensitisation to a food. It is sensitive but not specific: a positive result identifies sensitisation, which is common and frequently clinically irrelevant, so it supports rather than makes the diagnosis.

skin prick test NCIT:C85396

Show evidence (1 reference)

PMID:42358594 SUPPORT REVIEW SYNTHESIS Other

"However, SPT and sIgE are highly sensitive but lack specificity, frequently identifying clinically irrelevant sensitization"

Review characterising the sensitivity-without-specificity limitation of skin prick testing.

Serum allergen-specific IgE measurement

Measurement of serum IgE specific to a food allergen. Like the skin prick test it reports sensitisation, not clinical allergy, and shares the same specificity limitation.

serum allergen-specific IgE measurement NCIT:C81970

Show evidence (1 reference)

PMID:42358594 SUPPORT REVIEW SYNTHESIS Other

"Current diagnostic approaches rely on clinical history, skin prick tests (SPT), measurement of serum allergen-specific IgE (sIgE), and oral food challenges (OFC)."

Names serum allergen-specific IgE among the standard diagnostic approaches.

Oral food challenge

Supervised graded ingestion of the suspected food, the diagnostic gold standard. It is resource-demanding and carries a real risk of a systemic reaction, which is why it is reserved for cases the sensitisation tests leave unresolved.

oral food challenge

No NCIT term is bound. OLS NCIT searches for "Oral Food Challenge" and "food challenge" returned no clinical-intervention term for the procedure, so the identity is carried in preferred_term rather than a manufactured binding.

Show evidence (1 reference)

PMID:42358594 SUPPORT REVIEW SYNTHESIS Other

"OFC remains the diagnostic gold standard despite being resource-demanding and carrying a substantial risk of systemic reactions"

Establishes the oral food challenge as the diagnostic gold standard and its risk.

Serum tryptase measurement

Serum tryptase rises after mast-cell degranulation and is the laboratory marker used to confirm an anaphylactic event and to flag an underlying mast cell disorder. It reads out the degranulation node rather than diagnosing the sensitisation.

serum tryptase measurement NCIT:C92292

Show evidence (1 reference)

PMID:38108678 SUPPORT REVIEW SYNTHESIS Other

"Measurement of serum tryptase is important for diagnosis of anaphylaxis and to identify underlying mast cell disorders."

Practice-parameter statement that serum tryptase supports the diagnosis of anaphylaxis.

📊

Prevalence

3

United States, children

Point prevalence 7600.0 per 100,000 >1 in 1,000

7.6% of US children, for IgE-mediated food-protein allergy.

Show evidence (1 reference)

PMID:38349368 SUPPORT REVIEW SYNTHESIS Human clinical

"An estimated 7.6% of children and 10.8% of adults have IgE-mediated food-protein allergies in the US."

Gives the US paediatric prevalence of IgE-mediated food-protein allergy.

United States, adults

Point prevalence 10800.0 per 100,000 >1 in 1,000

10.8% of US adults. Adult estimates diverge widely by ascertainment method and this is the high end: a separate record on this entry carries the ~2% figure for Western countries. Read the two together rather than either alone -- the gap is a measurement disagreement (self-reported versus more conservative ascertainment), not a change over time, and dismech records both rather than averaging them.

Show evidence (1 reference)

PMID:38349368 SUPPORT REVIEW SYNTHESIS Human clinical

"An estimated 7.6% of children and 10.8% of adults have IgE-mediated food-protein allergies in the US."

Gives the US adult prevalence of IgE-mediated food-protein allergy.

Western countries, adults

Point prevalence 2000.0 per 100,000 >1 in 1,000

~2% of adults in Western countries, against 10.8% from the US estimate recorded separately above. Note this source's figure spans IgE- and non-IgE-mediated food allergic conditions together, so it is not a like-for-like comparison with the IgE-restricted US figure.

Show evidence (1 reference)

PMID:39257598 SUPPORT REVIEW SYNTHESIS Human clinical

"Food allergic (FA) conditions have been classified as immunoglobulin E (IgE) and non-IgE-mediated reactions that affect as many as 8% of young children and 2% of adults in Western countries, and their prevalence seems to be rising."

Gives the lower adult prevalence estimate for Western countries, across IgE- and non-IgE-mediated food allergy together.

{ }

Source YAML

click to show

name: Food Allergy
creation_date: '2026-10-23T00:00:00Z'
category: Complex
parents:
- Allergic Disease
- Immune-Mediated Disease
description: >-
  Food allergy is an adverse immune response to dietary antigens that is
  reproducible on re-exposure and distinct from food intolerance. The dominant
  form is IgE-mediated (type I) hypersensitivity to food proteins, in which
  failure of the default oral tolerance response to an ingested protein permits
  type 2 immune priming, allergen-specific IgE production, and arming of tissue
  mast cells and circulating basophils through the high-affinity IgE receptor
  FcepsilonRI. On re-exposure, multivalent allergen crosslinks receptor-bound
  IgE, aggregating FcepsilonRI and triggering degranulation with release of
  preformed and newly synthesised mediators that produce urticaria, angioedema,
  vomiting, bronchospasm, and in severe cases anaphylaxis. The characterised
  allergens of this form of disease are proteins, and their biochemical
  properties -- notably oligomeric assembly, which sets the number and spacing
  of IgE epitopes presented on one particle -- contribute to both sensitisation
  and effector potency. Management rests on avoidance of the culprit allergen
  and prompt epinephrine for systemic reactions.
synonyms:
- allergic disease from food material
- allergy of food material
- food material allergic disease
- IgE-mediated food allergy
- food hypersensitivity
disease_term:
  preferred_term: food allergy
  term:
    id: MONDO:0700226
    label: food allergy
notes: >-
  This entry is scoped to IgE-mediated allergy to food *proteins*. Alpha-gal
  syndrome is deliberately excluded and left for a separate entry: its
  sensitising epitope is a carbohydrate (galactose-alpha-1,3-galactose) rather
  than a protein, IgE is raised by tick bite rather than by ingestion, and the
  reaction is delayed rather than immediate. Writing a universal claim that all
  food allergens are proteins would be false for that entity, so the scope is
  stated here instead.

  The disease_term MONDO:0700226 is broader than the curated scope. Food
  allergy also covers non-IgE-mediated forms (food protein-induced
  enterocolitis syndrome, food protein-induced allergic proctocolitis) and the
  mixed form eosinophilic esophagitis. Those lack the IgE and mast-cell
  crosslinking steps modelled here and are curated as their own entries, so
  this entry anchors to the general term without modelling them.
prevalence:
- population: United States, children
  measure_type: POINT_PREVALENCE
  prevalence_class: ABOVE_1_IN_1000
  rate_per_100000: 7600.0
  rate_denominator: POPULATION
  notes: 7.6% of US children, for IgE-mediated food-protein allergy.
  evidence:
  - reference: PMID:38349368
    reference_title: Management of Food Allergies and Food-Related Anaphylaxis.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "An estimated 7.6% of children and 10.8% of adults have IgE-mediated food-protein allergies in the US."
    explanation: Gives the US paediatric prevalence of IgE-mediated food-protein allergy.
- population: United States, adults
  measure_type: POINT_PREVALENCE
  prevalence_class: ABOVE_1_IN_1000
  rate_per_100000: 10800.0
  rate_denominator: POPULATION
  notes: >-
    10.8% of US adults. Adult estimates diverge widely by ascertainment method
    and this is the high end: a separate record on this entry carries the ~2%
    figure for Western countries. Read the two together rather than either
    alone -- the gap is a measurement disagreement (self-reported versus more
    conservative ascertainment), not a change over time, and dismech records
    both rather than averaging them.
  evidence:
  - reference: PMID:38349368
    reference_title: Management of Food Allergies and Food-Related Anaphylaxis.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "An estimated 7.6% of children and 10.8% of adults have IgE-mediated food-protein allergies in the US."
    explanation: Gives the US adult prevalence of IgE-mediated food-protein allergy.
- population: Western countries, adults
  measure_type: POINT_PREVALENCE
  prevalence_class: ABOVE_1_IN_1000
  rate_per_100000: 2000.0
  rate_denominator: POPULATION
  notes: >-
    ~2% of adults in Western countries, against 10.8% from the US estimate
    recorded separately above. Note this source's figure spans IgE- and
    non-IgE-mediated food allergic conditions together, so it is not a
    like-for-like comparison with the IgE-restricted US figure.
  evidence:
  - reference: PMID:39257598
    reference_title: "IgE and non-IgE food allergy: A review of immunological mechanisms."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "Food allergic (FA) conditions have been classified as immunoglobulin E (IgE) and non-IgE-mediated reactions that affect as many as 8% of young children and 2% of adults in Western countries, and their prevalence seems to be rising."
    explanation: >-
      Gives the lower adult prevalence estimate for Western countries, across
      IgE- and non-IgE-mediated food allergy together.
genetic:
- name: FLG
  gene_term:
    preferred_term: FLG
    term:
      id: hgnc:3748
      label: FLG
  association: Associated
  relationship_type: RISK_FACTOR
  notes: >-
    Filaggrin is one of five genome-wide significant food-allergy loci and the
    epithelial-barrier arm of the genetic risk, shared with atopic dermatitis.
    It is a susceptibility factor, not a cause: most carriers never develop food
    allergy.
  evidence:
  - reference: PMID:29051540
    reference_title: Genome-wide association study identifies the SERPINB gene cluster as a susceptibility locus for food allergy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "We identify five loci at genome-wide significance, the clade B serpin (SERPINB) gene cluster at 18q21.3, the cytokine gene cluster at 5q31.1, the filaggrin gene, the C11orf30/LRRC32 locus, and the human leukocyte antigen (HLA) region."
    explanation: Names the filaggrin gene among the five genome-wide significant food-allergy loci.
  - reference: PMID:39698764
    reference_title: "Food Allergy Genetics and Epigenetics: A Review of Genome-Wide Association Studies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "Identified genes for food allergy are mainly involved in epithelial barrier function (e.g., FLG, SERPINB7) and immune function (e.g., HLA, IL4)."
    explanation: Review grouping FLG under the epithelial-barrier arm of food-allergy genetic risk.
- name: SERPINB10
  gene_term:
    preferred_term: SERPINB10
    term:
      id: hgnc:8942
      label: SERPINB10
  association: Associated
  relationship_type: RISK_FACTOR
  notes: >-
    The 18q21.3 clade B serpin cluster is the lead locus of the first
    food-allergy GWAS; the association tracks SERPINB10 expression in
    leukocytes, and the serpins are highly expressed in the esophagus.
  evidence:
  - reference: PMID:29051540
    reference_title: Genome-wide association study identifies the SERPINB gene cluster as a susceptibility locus for food allergy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "Variants in the SERPINB gene cluster are associated with SERPINB10 expression in leukocytes."
    explanation: Localises the 18q21.3 food-allergy association to SERPINB10 expression.
- name: IL4
  gene_term:
    preferred_term: IL4
    term:
      id: hgnc:6014
      label: IL4
  association: Associated
  relationship_type: RISK_FACTOR
  notes: >-
    IL4 sits in the 5q31.1 cytokine gene cluster, one of the five genome-wide
    significant loci, and is the immune-signalling arm of the risk; IL-4 is also
    the type 2 cytokine that licenses the IgE class switch modelled downstream.
  evidence:
  - reference: PMID:39698764
    reference_title: "Food Allergy Genetics and Epigenetics: A Review of Genome-Wide Association Studies."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "Identified genes for food allergy are mainly involved in epithelial barrier function (e.g., FLG, SERPINB7) and immune function (e.g., HLA, IL4)."
    explanation: Names IL4 as the immune-function arm of food-allergy genetic risk.
- name: EMSY
  gene_term:
    preferred_term: EMSY
    term:
      id: hgnc:18071
      label: EMSY
  association: Associated
  relationship_type: RISK_FACTOR
  notes: >-
    C11orf30/EMSY reached genome-wide significance for food allergy in a
    multi-population meta-analysis and is shared across allergic diseases; the
    locus is implicated in epigenetic regulation of gene expression.
  evidence:
  - reference: PMID:29030101
    reference_title: Genome-wide association study and meta-analysis in multiple populations identifies new loci for peanut allergy and establishes C11orf30/EMSY as a genetic risk factor for food allergy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "This study identifies multiple novel loci as risk factors for PA and food allergy and establishes C11orf30 as a risk locus for both PA and food allergy."
    explanation: Establishes C11orf30/EMSY as a genome-wide significant food-allergy risk locus.
pathophysiology:
- name: Dietary Protein Allergen Exposure
  biological_scale: ORGANISM
  description: >-
    Ingestion of an intact or partially digested food protein presents that
    protein to the gut mucosal immune system. A small number of foods account
    for the great majority of IgE-mediated disease, which is one reason allergen
    identity rather than diet composition in general is the exposure that
    matters.
  downstream:
  - target: Oligomeric Allergen Epitope Display
    description: >-
      The ingested protein reaches the mucosa as an assembled particle, so its
      native quaternary structure determines how many IgE epitopes are presented
      together.
  evidence:
  - reference: PMID:38349368
    reference_title: Management of Food Allergies and Food-Related Anaphylaxis.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In the US, 9 foods account for more than 90% of IgE-mediated food allergies-crustacean shellfish, dairy, peanut, tree nuts, fin fish, egg, wheat, soy, and sesame."
    explanation: Establishes that a small set of food proteins dominates IgE-mediated food allergy.
- name: Oligomeric Allergen Epitope Display
  biological_scale: MOLECULAR
  description: >-
    Many major food allergens are not monomers. Native Ara h 1, the peanut 7S
    vicilin, assembles into higher-order homo-oligomers (nonamer or decamer),
    and a truncated 54 kDa isoform lacking the N-terminal domain is instead
    exclusively trimeric -- which localises the higher-order oligomerisation
    interface to that N-terminal domain. The cow's milk whey lipocalin
    beta-lactoglobulin (Bos d 5) likewise associates into dimers in solution.
    Because oligomerisation multiplies the copies of an epitope carried on one
    particle, this quaternary structure sets the valency available for
    downstream FcepsilonRI crosslinking, and the oligomerisation interface is
    therefore a structural determinant of effector potency rather than an
    incidental biophysical property. The epitopes must also be *accessible*: in
    beta-lactoglobulin, occupancy of the lipocalin ligand pocket is predicted to
    mask major IgE and T-cell epitopes, so the same protein displays different
    epitope surfaces in its ligand-free and ligand-loaded states.
  molecular_functions: []
  biological_processes:
  - preferred_term: allergen homo-oligomerisation
    term:
      id: GO:0051260
      label: protein homooligomerization
  downstream:
  - target: Failure of Oral Tolerance Induction
    description: >-
      Ligand-free beta-lactoglobulin presents unmasked IgE and T-cell epitopes
      and behaves as an allergen, whereas the ligand-loaded form supports a
      tolerogenic outcome.
  - target: Multivalent FcepsilonRI Crosslinking
    description: >-
      An oligomeric allergen presents two or more spatially arranged IgE
      epitopes on one particle, which is the minimum requirement for
      productive receptor crosslinking.
  evidence:
  - reference: PMID:33439436
    reference_title: "Purification and molecular characterization of a truncated-type Ara h 1, a major peanut allergen: oligomer structure, antigenicity, and glycoform."
    supports: SUPPORT
    evidence_source: IN_VITRO
    directness: DIRECT
    snippet: "We found that 63 kDa Ara h 1 occurs as higher order homo-oligomeric conformations such as decamer or nonamer, while 54 kDa Ara h 1 occurs exclusively as a homotrimer, indicating that the N-terminal domain of the 63 kDa molecule may be involved in higher order oligomerization."
    explanation: >-
      Establishes both the oligomeric state of a major peanut allergen and the
      location of the interface driving higher-order assembly, by contrasting
      the full-length protein with an N-terminally truncated isoform.
  - reference: PMID:30923869
    reference_title: "β-Lactoglobulin associative interactions: a small-angle scattering study."
    supports: SUPPORT
    evidence_source: IN_VITRO
    directness: DIRECT
    snippet: "it was shown that β-lg forms dimeric structures in 50 mM HEPES buffer under various conditions of the medium"
    explanation: >-
      Small-angle scattering evidence that beta-lactoglobulin self-associates
      into dimers, giving a second, non-legume example of an oligomeric food
      allergen.
  - reference: PMID:32485264
    reference_title: "Cow's milk protein β-lactoglobulin confers resilience against allergy by targeting complexed iron into immune cells."
    supports: SUPPORT
    evidence_source: COMPUTATIONAL
    directness: INDIRECT
    snippet: "Modeling predicted masking of major IgE and T-cell epitopes of BLG by ligand binding."
    explanation: >-
      Docking and modelling result predicting that ligand occupancy of the
      beta-lactoglobulin pocket occludes its major IgE and T-cell epitopes, so
      epitope accessibility is state-dependent. Graded COMPUTATIONAL and
      INDIRECT because the quoted claim is a prediction; the experimental
      confirmation is cited separately on the tolerance node.
- name: Failure of Oral Tolerance Induction
  biological_scale: CELLULAR
  description: >-
    The default response to a dietary protein is peripheral tolerance, in which
    a specialised RORgt- and PRDM16-dependent lineage of intestinal
    antigen-presenting cells drives antigen-specific peripherally induced
    regulatory T cells. Food allergy begins when this programme is not engaged
    for a given protein and the response is instead primed toward type 2
    immunity. The beta-lactoglobulin ligand-state experiments show that the same
    protein can take either route: loaded holo-beta-lactoglobulin prevented
    sensitisation while sustaining regulatory T cells, whereas the ligand-free
    apo form acted as an allergen -- a demonstration that tolerance versus
    sensitisation can be decided by the allergen's own loading state rather than
    by its sequence.
  cell_types:
  - preferred_term: tolerogenic RORgt+ PRDM16+ intestinal antigen-presenting cell
    term:
      id: CL:0000145
      label: professional antigen presenting cell
  - preferred_term: peripherally induced regulatory T cell
    term:
      id: CL:0000815
      label: regulatory T cell
  biological_processes:
  - preferred_term: oral tolerance induction to dietary protein
    modifier: DECREASED
    term:
      id: GO:0002507
      label: tolerance induction
  notes: >-
    The tolerogenic APC is bound to CL:0000145 professional antigen presenting
    cell, the nearest term the cited lineage is a kind of, not to a dendritic
    cell term. PMID:41328802 defines this RORgt+/PRDM16+ lineage (Thetis cells)
    by contrast with conventional dendritic cells, so CL:0000990 conventional
    dendritic cell would assert the identity the source sets it apart from. OLS
    CL searches for "antigen presenting cell RORgt", "RORgt" and "Thetis"
    returned no lineage-specific term, so the specificity is carried in
    preferred_term rather than in a manufactured narrow binding.
  downstream:
  - target: Type 2 Immune Reprogramming
    description: >-
      With the tolerogenic programme not engaged, the allergen-specific response
      is primed toward type 2 immunity instead.
  evidence:
  - reference: PMID:41328802
    reference_title: Specialized Dendritic Cells Mediating Peripheral Tolerance to Intestinal Antigens.
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: "Recent studies have revealed that intestinal antigen-specific pTreg cell differentiation is induced by a distinct lineage of antigen-presenting cells (APCs) requiring expression of the transcription factors RORγt and PRDM16."
    explanation: >-
      Identifies the antigen-presenting cell lineage and transcription factors
      required for peripheral tolerance to dietary antigens, which is the
      programme whose failure this node describes. Graded OTHER with
      REVIEW_SYNTHESIS because the quoted sentence is a review's synthesis of
      work it did not perform.
  - reference: PMID:32485264
    reference_title: "Cow's milk protein β-lactoglobulin confers resilience against allergy by targeting complexed iron into immune cells."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    directness: DIRECT
    snippet: "In mice, only treatments with holoBLG prevented allergic sensitization and anaphylaxis, while sustaining regulatory T cells."
    explanation: >-
      In vivo demonstration that the ligand-loaded state of beta-lactoglobulin
      prevents sensitisation and maintains regulatory T cells, supporting the
      tolerance arm of this node.
  - reference: PMID:32485264
    reference_title: "Cow's milk protein β-lactoglobulin confers resilience against allergy by targeting complexed iron into immune cells."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    directness: INDIRECT
    snippet: "Our data provide a mechanistic explanation why the same proteins can act either as tolerogens or as allergens."
    explanation: >-
      The authors' own statement of the general principle this node encodes:
      tolerance versus sensitisation is not fixed by the protein's identity
      alone.
- name: Type 2 Immune Reprogramming
  biological_scale: CELLULAR
  description: >-
    The allergen-specific CD4 T cell response is redirected toward a T-helper 2
    programme, with group 2 innate lymphoid cells contributing innate type 2
    cytokine production. IL-4 and IL-13 from this compartment are the signals
    that license the B cell switch to IgE, making this the step at which a
    tolerogenic response is converted into a sensitising one.
  cell_types:
  - preferred_term: allergen-specific T-helper 2 cell
    term:
      id: CL:0000546
      label: T-helper 2 cell
  - preferred_term: group 2 innate lymphoid cell
    term:
      id: CL:0001069
      label: group 2 innate lymphoid cell
  biological_processes:
  - preferred_term: type 2 immune response to dietary allergen
    modifier: INCREASED
    term:
      id: GO:0042092
      label: type 2 immune response
  - preferred_term: T-helper 2 cell differentiation
    modifier: INCREASED
    term:
      id: GO:0045064
      label: T-helper 2 cell differentiation
  downstream:
  - target: IgE Class Switching and FcepsilonRI Arming
    description: >-
      Type 2 cytokines, principally IL-4 and IL-13, drive the immunoglobulin
      heavy-chain switch to IgE in allergen-specific B cells.
- name: IgE Class Switching and FcepsilonRI Arming
  biological_scale: MOLECULAR
  description: >-
    Allergen-specific B cells switch to the IgE isotype and differentiate into
    IgE-secreting plasma cells. Secreted IgE binds the high-affinity receptor
    FcepsilonRI on tissue mast cells and circulating basophils, arming them for
    an allergen-specific response. Sensitisation is clinically silent at this
    point; the disease becomes manifest only on re-exposure, which is why
    anaphylaxis is not expected on a genuinely first exposure.
  cell_types:
  - preferred_term: IgE-secreting plasma cell
    term:
      id: CL:0000947
      label: IgE plasma cell
  biological_processes:
  - preferred_term: isotype switching to IgE
    modifier: INCREASED
    term:
      id: GO:0048289
      label: isotype switching to IgE isotypes
  downstream:
  - target: Multivalent FcepsilonRI Crosslinking
    description: >-
      Receptor-bound allergen-specific IgE is the substrate that an incoming
      multivalent allergen crosslinks.
  evidence:
  - reference: PMID:41715900
    reference_title: Mechanisms of IgE-mediated food allergy and the role of allergen-specific B cells.
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: "CD4+ cells, especially Tfh, play a fundamental role in the sequential class switching of memory B cells in germinal centers to convert them into IgE‐producing cells."
    explanation: >-
      Supports the dependence of the IgE class switch on CD4 T cell help,
      linking the type 2 node upstream to IgE production at this node. Graded
      OTHER with REVIEW_SYNTHESIS because the quoted sentence is a review's
      synthesis rather than its own experimental result.
  - reference: PMID:41715900
    reference_title: Mechanisms of IgE-mediated food allergy and the role of allergen-specific B cells.
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: "Chronic allergen exposure promotes the accumulation of long‐lived IgE plasma cells in the bone marrow, thereby sustaining enduring serological memory and contributing to the persistence of allergic disease"
    explanation: >-
      Accounts for why sensitisation persists once established, which is the
      reason avoidance rather than clearance of IgE is the mainstay of
      management.
- name: Multivalent FcepsilonRI Crosslinking
  biological_scale: MOLECULAR
  description: >-
    An allergen bearing two or more IgE epitopes bridges adjacent IgE-FcepsilonRI
    complexes, and the resulting receptor aggregate initiates signalling. Valency
    and epitope spacing are not merely permissive: tetravalent antigen produces
    larger, more complex aggregates and stronger responses than bivalent antigen,
    can signal at low IgE occupancy, and the geometry of the aggregate determines
    signalling efficiency. This is the step at which the oligomeric state of the
    allergen is converted into a quantitative difference in effector output.
  cell_types:
  - preferred_term: mast cell
    term:
      id: CL:0000097
      label: mast cell
  - preferred_term: basophil
    term:
      id: CL:0000767
      label: basophil
  biological_processes:
  - preferred_term: Fc-epsilon receptor signaling pathway
    modifier: INCREASED
    term:
      id: GO:0038095
      label: Fc-epsilon receptor signaling pathway
  downstream:
  - target: Mast Cell and Basophil Degranulation
    description: >-
      Aggregated FcepsilonRI signals through Lyn and Syk to calcium mobilisation
      and granule exocytosis, with aggregate geometry setting the efficiency of
      that coupling.
  evidence:
  - reference: PMID:42589421
    reference_title: IgE Occupancy and Antigen Valency Cooperate to Control FcεRI Aggregation Geometry and Signaling Efficiency.
    supports: SUPPORT
    evidence_source: IN_VITRO
    directness: INDIRECT
    snippet: "Thus, allergen valency and epitope spatial arrangement dictate FcεRI aggregate organization and subsequent effector cell activation."
    explanation: >-
      Primary conclusion that allergen valency and epitope arrangement control
      receptor aggregate organisation and effector activation. Graded INDIRECT
      because the valency series was built from a grass-pollen (Phl p 1) epitope
      grafted onto a myoglobin scaffold rather than from a food allergen, so the
      principle transfers by inference.
  - reference: PMID:42589421
    reference_title: IgE Occupancy and Antigen Valency Cooperate to Control FcεRI Aggregation Geometry and Signaling Efficiency.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: BACKGROUND
    directness: DIRECT
    snippet: "It has been well established that at least two IgE epitopes are required on an allergen to induce effector cell degranulation, and that increases in valency trigger even stronger responses"
    explanation: >-
      States the established minimum-valency requirement that makes allergen
      oligomerisation mechanistically load-bearing. Marked BACKGROUND because the
      sentence sits in this paper's introduction and restates work it cites
      rather than its own result.
- name: Mast Cell and Basophil Degranulation
  biological_scale: CELLULAR
  description: >-
    FcepsilonRI signalling triggers calcium influx and exocytosis of preformed
    granule contents, principally histamine and tryptase, together with newly
    generated lipid mediators. This is the effector event that produces the
    clinical reaction, and it is the step whose systemic consequences epinephrine
    is given to reverse. Serum tryptase released here is also the diagnostic
    marker of an anaphylactic event.
  cell_types:
  - preferred_term: mucosal mast cell
    term:
      id: CL:0000485
      label: mucosal type mast cell
  - preferred_term: basophil
    term:
      id: CL:0000767
      label: basophil
  biological_processes:
  - preferred_term: mast cell degranulation
    modifier: INCREASED
    term:
      id: GO:0043303
      label: mast cell degranulation
  - preferred_term: IgE-mediated histamine secretion
    modifier: INCREASED
    term:
      id: GO:0097279
      label: histamine secretion mediated by IgE immunoglobulin
  downstream:
  - target: Urticaria
    description: Histamine-driven dermal vasodilatation and wheal formation.
  - target: Angioedema
    description: Mediator-driven deep dermal and submucosal extravasation.
  - target: Vomiting
    description: Gastrointestinal mediator release on mucosal allergen contact.
  - target: Wheezing
    description: Mediator-driven bronchial smooth muscle constriction.
  - target: Hypotension
    description: >-
      Systemic mediator release causes vasodilatation and capillary leak,
      the circulatory failure of anaphylaxis.
  - target: Food-induced anaphylaxis
    description: >-
      Simultaneous multi-system mediator effects constitute the anaphylactic
      syndrome.
  evidence:
  - reference: PMID:42589421
    reference_title: IgE Occupancy and Antigen Valency Cooperate to Control FcεRI Aggregation Geometry and Signaling Efficiency.
    supports: SUPPORT
    evidence_source: IN_VITRO
    directness: INDIRECT
    snippet: "Tetravalent MB4N evoked stronger degranulation and Ca2+ response than bivalent antigens MB1N1C and MB2N."
    explanation: >-
      Measures degranulation and calcium response as a function of antigen
      valency, linking allergen multivalency quantitatively to this node's
      output. INDIRECT because the antigen series is a scaffold construct rather
      than a food allergen.
  - reference: PMID:32485264
    reference_title: "Cow's milk protein β-lactoglobulin confers resilience against allergy by targeting complexed iron into immune cells."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    directness: DIRECT
    snippet: "In line with this modeling, IgE binding in children allergic to milk was reduced toward holoBLG, which also impaired degranulation of mast cells."
    explanation: >-
      Shows with sera from milk-allergic children that reducing accessible IgE
      epitopes on beta-lactoglobulin reduces IgE binding and impairs mast cell
      degranulation, connecting epitope display to this effector node in human
      material.
phenotypes:
- name: Food-induced anaphylaxis
  category: Systemic
  description: >-
    Acute multi-system reaction after ingestion of the culprit food, which may
    include airway compromise and circulatory collapse and is the cause of the
    rare fatalities in this disease.
  phenotype_term:
    preferred_term: Food-induced anaphylaxis
    term:
      id: HP:0500095
      label: Food-induced anaphylaxis
    temporality: ACUTE
  evidence:
  - reference: PMID:38349368
    reference_title: Management of Food Allergies and Food-Related Anaphylaxis.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "IgE-mediated food allergies may cause anaphylaxis and death."
    explanation: Establishes anaphylaxis and death as outcomes of IgE-mediated food allergy.
- name: Urticaria
  category: Dermatologic
  description: Pruritic wheals following allergen ingestion.
  phenotype_term:
    preferred_term: Urticaria
    term:
      id: HP:0001025
      label: Urticaria
    temporality: ACUTE
- name: Angioedema
  category: Dermatologic
  description: Deep dermal or submucosal swelling, characteristically of lips, face, or airway.
  phenotype_term:
    preferred_term: Angioedema
    term:
      id: HP:0100665
      label: Angioedema
    temporality: ACUTE
- name: Vomiting
  category: Gastrointestinal
  description: Emesis shortly after ingestion of the culprit allergen.
  phenotype_term:
    preferred_term: Vomiting
    term:
      id: HP:0002013
      label: Vomiting
    temporality: ACUTE
- name: Wheezing
  category: Respiratory
  description: Bronchospasm during a systemic allergic reaction.
  phenotype_term:
    preferred_term: Wheezing
    term:
      id: HP:0030828
      label: Wheezing
    temporality: ACUTE
- name: Hypotension
  category: Cardiovascular
  description: Circulatory failure from vasodilatation and capillary leak in anaphylaxis.
  phenotype_term:
    preferred_term: Hypotension
    term:
      id: HP:0002615
      label: Hypotension
    temporality: ACUTE
environmental:
- name: Early oral introduction of allergenic food
  exposure_term:
    preferred_term: early oral exposure to food allergen in infancy
    term:
      id: ECTO:0000726
      label: exposure to allergen
  effect: PROTECTS_AGAINST
  description: >-
    Introducing an allergenic food by mouth during infancy, rather than
    delaying it, engages oral tolerance and prevents allergy. In LEAP the
    protection persisted to age 12, and a pooled LEAP+EAT analysis showed a 75%
    reduction in peanut allergy; the benefit shrinks the later introduction is
    delayed, which is the opposite of the predisposing exposure on the skin arm
    below.
  influences_mechanisms:
  - target: Failure of Oral Tolerance Induction
    environmental_effect: PROTECTS_AGAINST
    causal_link_type: DIRECT
    description: >-
      Early oral exposure drives the peripheral-tolerance programme for the
      food protein, so this node's failure is averted rather than triggered.
    evidence:
    - reference: PMID:38804779
      reference_title: Follow-up to Adolescence after Early Peanut Introduction for Allergy Prevention.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "peanut allergy remained significantly more prevalent in participants in the original peanut avoidance group than in the original peanut consumption group"
      explanation: >-
        LEAP follow-up to age 12: oral peanut from infancy roughly a third of
        the allergy rate of avoidance, supporting oral exposure acting on the
        tolerance node.
  evidence:
  - reference: PMID:36435990
    reference_title: "Early introduction of peanut reduces peanut allergy across risk groups in pooled and causal inference analyses."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "An intention-to-treat (ITT) analysis of pooled data showed a 75% reduction in PA (p < .0001) among children randomized to consume peanut from early infancy."
    explanation: Pooled LEAP+EAT randomised data quantifying the protective effect of early oral introduction.
  - reference: PMID:36521802
    reference_title: Defining the window of opportunity and target populations to prevent peanut allergy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The preventive benefit of early introduction of peanut products into the diet decreases as age at introduction increases."
    explanation: Establishes the age-dependent window over which the protective effect operates.
- name: Cutaneous allergen exposure through an impaired skin barrier
  exposure_term:
    preferred_term: cutaneous exposure to food allergen through inflamed or barrier-impaired skin
    term:
      id: ECTO:0000726
      label: exposure to allergen
  effect: PREDISPOSES
  description: >-
    The dual-allergen-exposure hypothesis holds that encountering a food
    allergen across inflamed or barrier-impaired skin (as in atopic dermatitis)
    primes sensitisation, while the same allergen taken orally promotes
    tolerance. The outcome is context-dependent: healthy skin promotes
    tolerance, and only about a third of children with atopic dermatitis go on
    to a food allergy, so this is a predisposing route rather than a sufficient
    cause.
  influences_mechanisms:
  - target: Type 2 Immune Reprogramming
    environmental_effect: PREDISPOSES
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Cutaneous exposure on inflamed skin routes the allergen-specific response
      toward type 2 priming instead of tolerance, predisposing to the
      reprogramming node.
    evidence:
    - reference: PMID:38740132
      reference_title: The riddle of response to cutaneous allergen exposure in patients with atopic dermatitis.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The dual allergen exposure hypothesis posits that sensitization to food allergens may occur with cutaneous exposure on inflamed skin, eg, atopic dermatitis, but early oral consumption generally leads to tolerance."
      explanation: States the cutaneous-sensitisation versus oral-tolerance contrast this link encodes.
  evidence:
  - reference: PMID:41967460
    reference_title: Food allergy prevention by early introduction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "The dual-allergen exposure hypothesis suggests that impaired skin barrier exposure leads to sensitization, whereas early oral intake induces tolerance."
    explanation: Review statement of the dual-allergen-exposure hypothesis grounding this exposure.
diagnosis:
- name: Skin prick testing
  description: >-
    A skin prick test detects IgE sensitisation to a food. It is sensitive but
    not specific: a positive result identifies sensitisation, which is common
    and frequently clinically irrelevant, so it supports rather than makes the
    diagnosis.
  diagnosis_term:
    preferred_term: skin prick test
    term:
      id: NCIT:C85396
      label: Skin Prick Test
  evidence:
  - reference: PMID:42358594
    reference_title: "Innovative diagnostic techniques and their clinical implications in food allergy: current clinical practice and future perspectives."
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: "However, SPT and sIgE are highly sensitive but lack specificity, frequently identifying clinically irrelevant sensitization"
    explanation: Review characterising the sensitivity-without-specificity limitation of skin prick testing.
- name: Serum allergen-specific IgE measurement
  description: >-
    Measurement of serum IgE specific to a food allergen. Like the skin prick
    test it reports sensitisation, not clinical allergy, and shares the same
    specificity limitation.
  diagnosis_term:
    preferred_term: serum allergen-specific IgE measurement
    term:
      id: NCIT:C81970
      label: Immunoglobulin E Measurement
  evidence:
  - reference: PMID:42358594
    reference_title: "Innovative diagnostic techniques and their clinical implications in food allergy: current clinical practice and future perspectives."
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: "Current diagnostic approaches rely on clinical history, skin prick tests (SPT), measurement of serum allergen-specific IgE (sIgE), and oral food challenges (OFC)."
    explanation: Names serum allergen-specific IgE among the standard diagnostic approaches.
- name: Oral food challenge
  description: >-
    Supervised graded ingestion of the suspected food, the diagnostic gold
    standard. It is resource-demanding and carries a real risk of a systemic
    reaction, which is why it is reserved for cases the sensitisation tests
    leave unresolved.
  diagnosis_term:
    preferred_term: oral food challenge
  notes: >-
    No NCIT term is bound. OLS NCIT searches for "Oral Food Challenge" and
    "food challenge" returned no clinical-intervention term for the procedure,
    so the identity is carried in preferred_term rather than a manufactured
    binding.
  evidence:
  - reference: PMID:42358594
    reference_title: "Innovative diagnostic techniques and their clinical implications in food allergy: current clinical practice and future perspectives."
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: "OFC remains the diagnostic gold standard despite being resource-demanding and carrying a substantial risk of systemic reactions"
    explanation: Establishes the oral food challenge as the diagnostic gold standard and its risk.
- name: Serum tryptase measurement
  description: >-
    Serum tryptase rises after mast-cell degranulation and is the laboratory
    marker used to confirm an anaphylactic event and to flag an underlying mast
    cell disorder. It reads out the degranulation node rather than diagnosing
    the sensitisation.
  diagnosis_term:
    preferred_term: serum tryptase measurement
    term:
      id: NCIT:C92292
      label: Tryptase Measurement
  evidence:
  - reference: PMID:38108678
    reference_title: "Anaphylaxis: A 2023 practice parameter update."
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: "Measurement of serum tryptase is important for diagnosis of anaphylaxis and to identify underlying mast cell disorders."
    explanation: Practice-parameter statement that serum tryptase supports the diagnosis of anaphylaxis.
treatments:
- name: Culprit Allergen Avoidance
  description: >-
    Strict dietary exclusion of the identified allergen. This remains the
    cornerstone of management and the only intervention that prevents reactions
    rather than treating them.
  therapeutic_modality: BEHAVIORAL
  treatment_term:
    preferred_term: allergen elimination diet
    term:
      id: NCIT:C219792
      label: Allergen Elimination Diet
  target_mechanisms:
  - target: Dietary Protein Allergen Exposure
    description: >-
      Avoidance acts at the exposure node, removing the antigen that would
      otherwise reach armed effector cells.
  evidence:
  - reference: PMID:38349368
    reference_title: Management of Food Allergies and Food-Related Anaphylaxis.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The cornerstone of IgE-food allergy management is avoidance of the culprit food allergen."
    explanation: States allergen avoidance as the cornerstone of management.
- name: Epinephrine
  description: >-
    Prompt intramuscular epinephrine, usually by self-injectable autoinjector,
    is the first-line treatment for food-related anaphylaxis. It does not act on
    the allergic mechanism upstream of degranulation; it opposes the systemic
    consequences of mediator release through alpha-1-mediated vasoconstriction
    and beta-2-mediated bronchodilation.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: epinephrine
      term:
        id: CHEBI:33568
        label: adrenaline
  target_mechanisms:
  - target: Hypotension
    description: >-
      Alpha-1 adrenergic vasoconstriction reverses the vasodilatation and
      capillary leak produced by systemic mediator release.
  - target: Wheezing
    description: Beta-2 adrenergic bronchodilation opposes mediator-driven bronchospasm.
  evidence:
  - reference: PMID:38349368
    reference_title: Management of Food Allergies and Food-Related Anaphylaxis.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Self-injectable epinephrine is the first-line treatment for food-related anaphylaxis."
    explanation: Establishes epinephrine as first-line treatment for food-related anaphylaxis.
- name: Peanut Oral Immunotherapy (AR101)
  description: >-
    Escalating-dose oral immunotherapy with a characterised peanut protein
    product, FDA-approved for peanut allergy. It raises the dose tolerated at
    challenge and reduces symptom severity on exposure, but it is an adjunct to
    avoidance and epinephrine rather than a replacement: it desensitises rather
    than curing, and patients continue to carry epinephrine.
  therapeutic_modality: OTHER
  treatment_term:
    preferred_term: oral immunotherapy
    term:
      id: NCIT:C15262
      label: Immunotherapy
  notes: >-
    No therapeutic_agent is bound. The characterised drug product is defatted
    peanut flour (AR101 / Palforzia); OLS NCIT searches for "Peanut Allergen
    Powder", "AR101", "Palforzia" and "defatted peanut flour" returned no
    pharmacologic-substance term, and NCIT:C189453 Arachis hypogaea Antigen
    sits under Allergen/Antigen rather than NCIT:C1909 Pharmacologic Substance,
    so it is outside the ChemicalEntityTerm enum and cannot occupy that slot.
  target_mechanisms:
  - target: Multivalent FcepsilonRI Crosslinking
    description: >-
      Desensitisation raises the allergen dose required to produce a reaction,
      acting on the threshold at which effector crosslinking becomes clinically
      significant.
  evidence:
  - reference: PMID:30449234
    reference_title: AR101 Oral Immunotherapy for Peanut Allergy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "AR101 resulted in higher doses of peanut protein that could be ingested without dose-limiting symptoms and in lower symptom severity during peanut exposure at the exit food challenge than placebo."
    explanation: >-
      Phase 3 randomised trial result establishing the desensitising effect and
      its limits.
- name: Omalizumab
  description: >-
    Omalizumab is an anti-IgE monoclonal antibody, FDA-approved for reducing
    allergic reactions to foods in patients with one or more food allergies. It
    sequesters free IgE so that less is available to arm FcepsilonRI on mast
    cells and basophils, raising the reaction threshold across multiple foods at
    once. Like oral immunotherapy it raises the threshold rather than curing,
    and patients continue to avoid the culprit foods and carry epinephrine.
  therapeutic_modality: MONOCLONAL_ANTIBODY
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: omalizumab
      term:
        id: NCIT:C29299
        label: Omalizumab
  target_mechanisms:
  - target: IgE Class Switching and FcepsilonRI Arming
    description: >-
      By binding free IgE, omalizumab lowers the pool available to arm
      FcepsilonRI, acting on the arming step upstream of crosslinking.
  evidence:
  - reference: PMID:38407394
    reference_title: Omalizumab for the Treatment of Multiple Food Allergies.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A total of 79 of the 118 participants (67%) receiving omalizumab met the primary end-point criteria, as compared with 4 of the 59 participants (7%) receiving placebo (P<0.001)."
    explanation: >-
      OUtMATCH phase 3 randomised result: omalizumab monotherapy raised the
      peanut reaction threshold far more than placebo, the trial behind the FDA
      approval.

📚

References & Deep Research

Deep Research

1

Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.

Evaluations and curation notes (1)

Create: Food Allergy · 2026-10-23T14:34:10Z · View source

New entry for IgE-mediated food allergy to protein allergens, anchored on MONDO:0700226. Scoped deliberately to protein allergens, with a notes field recording why alpha-gal syndrome is excluded (carbohydrate epitope, tick-bite sensitisation, delayed reaction) rather than asserting a universal that all food allergens are proteins. Seven-node pathograph from dietary protein exposure through to the clinical reaction, built around four emphases requested by a UNC researcher in session: (1) reprogramming of signalling pathways, curated as failure of RORgt/PRDM16-dependent tolerogenic antigen presentation and peripheral Treg induction, then type 2 reprogramming and IgE class switch; (2) allergen oligomerisation interfaces, curated as a dedicated Oligomeric Allergen Epitope Display node; (3) mast cell and basophil degranulation as the effector node; (4) avoidance and epinephrine as the treatment mainstay, with AR101 oral immunotherapy recorded as an adjunct that desensitises without replacing epinephrine. Deep research: falcon was requested but returned 403 ProviderAuthError (EDISON_API_KEY invalid or lacking endpoint access). Re-run with dr_fallback='--fallback' on the user's instruction; openscientist produced the report, which is named for openscientist and carries fell_back/requested_provider/provider_attempts in its frontmatter. Report validation read before use: references 44/44 resolved, confabulation_rate 0.0, 36/44 on topic; terms 37/43 resolved with 1 obsolete (NCIT:C2175, unrelated to this entry and not bound) and 3 reported label mismatches which on inspection are artifacts of the report placing frequency percentages in its label column -- HP:0001025, HP:0100665 and HP:0001047 are correctly identified, and the two I bound were independently resolved from OLS before the report existed. The report does not mention oligomerisation, valency, Ara h 1 or beta-lactoglobulin anywhere, so the oligomerisation arm was curated entirely from primary literature found by direct PubMed search: PMID:33439436 for Ara h 1 occurring as nonamer/decamer with the N-terminal domain as the higher-order oligomerisation interface (this also corrected an initial assumption that native Ara h 1 is trimeric -- the trimer is the truncated 54 kDa isoform), PMID:30923869 for beta-lactoglobulin dimerisation, and PMID:42589421 for valency and epitope spacing dictating FcepsilonRI aggregate geometry and degranulation. On the researcher's request to include variants of beta-lactoglobulin: no literature was found tying the bovine A/B genetic variants to allergenicity or IgE crosslinking (that literature is dairy-production: cheese yield, milk composition), so no such claim was written. The defensible variant axis is ligand-loading state, curated from PMID:32485264 -- modelling predicts ligand binding masks major IgE and T-cell epitopes, holo-BLG reduced IgE binding from milk-allergic children and impaired mast cell degranulation, and only holo-BLG prevented sensitisation in mice while sustaining Tregs. Prevalence records both the 7.6% paediatric / 10.8% adult US figures (PMID:38349368) and the ~2% adult Western figure (PMID:39257598), with notes recording that the adult gap is a measurement disagreement rather than a trend and that the lower figure spans IgE and non-IgE conditions, rather than averaging them. Validation: just validate-disorders passes with 20/20 snippets and 20/20 titles verified; term validation passes; check-causal-targets, check-entity-refs, check-duplicate-keys, check-enum-values, check-qualifier-terms and check-shared-disease-terms all clean. check-genereviews --online reports NO_CHAPTER with synonyms present, as expected for a complex non-Mendelian disease. One reference_title was initially written from inference and was corrected against the cached title before commit.

OpenScientist ▸

Food Allergy (MONDO:0700226) — Comprehensive Disease Characteristics Report

openscientist-autonomous 44 citations 2026-10-23T14:28:01.751351

Food Allergy (MONDO:0700226) — Comprehensive Disease Characteristics Report

Summary

Food allergy is a common, complex, polygenic immune-mediated disease with no single causal gene. Unlike Mendelian disorders named after one locus, food allergy (MONDO:0700226) arises from the interaction of many susceptibility genes — primarily epithelial-barrier genes (FLG/filaggrin, the SERPINB clade B serpin cluster at 18q21.3) and type-2 immune genes (the HLA region [peanut-specific], the IL4/IL13 cytokine cluster at 5q31.1, and C11orf30/EMSY at 11q13.5) — with a large environmental/exposome contribution. Because the research template requests a "causal gene" but food allergy is categorized as Complex, the correct answer is that susceptibility is distributed polygenically; the most robustly replicated genome-wide significant loci are FLG, the SERPINB cluster, HLA, the 5q31.1 cytokine cluster, and C11orf30/EMSY (PMID: 29051540, PMID: 29030101, PMID: 39698764).

The classic IgE-mediated form of the disease results from a failure of oral tolerance. Allergen crosses a compromised epithelial barrier, pathogenic Th2 lymphocytes drive B-cell class-switching to allergen-specific IgE, IgE arms mast cells and basophils via FcεRI, and on re-exposure the cross-linking of surface IgE triggers explosive degranulation — releasing histamine and proteases that produce urticaria, angioedema, gastrointestinal, respiratory and cardiovascular symptoms, and potentially fatal anaphylaxis. Food allergy affects as many as 8% of young children and 2% of adults in Western countries and its prevalence is rising. The disease spans IgE-mediated, non-IgE-mediated (e.g., FPIES, allergic proctocolitis), and mixed (eosinophilic esophagitis) subtypes, and it imposes a heavy psychosocial and quality-of-life burden on patients and caregivers.

Management rests on allergen avoidance plus emergency intramuscular adrenaline (epinephrine) for acute reactions, with two disease-modifying strategies now established: oral immunotherapy (OIT) and omalizumab (anti-IgE, now FDA-approved for food allergy). The single most important advance in prevention is the paradigm shift demonstrated by the LEAP and EAT trials: early oral introduction of allergenic foods in infancy prevents food allergy, reversing decades of avoidance-based advice. This report synthesizes 14 confirmed findings across all 15 requested sections, grounded in 58 reviewed papers.

Key Findings

Finding 1 — Food allergy is polygenic: barrier genes + type-2 immune genes

Food allergy has no single Mendelian cause. A genome-wide association study of oral-food-challenge–diagnosed food allergy (497 cases / 2,387 controls) identified five loci at genome-wide significance: the clade B serpin (SERPINB) gene cluster at 18q21.3, the cytokine gene cluster at 5q31.1 (which includes IL4/IL13), the filaggrin gene (FLG), the C11orf30/LRRC32 locus, and the HLA region. Notably the HLA association is peanut-specific (PMID: 29051540):

"We identify five loci at genome-wide significance, the clade B serpin (SERPINB) gene cluster at 18q21.3, the cytokine gene cluster at 5q31.1, the filaggrin gene, the C11orf30/LRRC32 locus, and the human leukocyte antigen (HLA) region."

A multi-population meta-analysis established C11orf30/EMSY as a genetic risk factor for food allergy generally and found ITGA6 near genome-wide significance for peanut allergy; several implicated genes (C11orf30/EMSY, SKAP1, CTNNA3) are involved in epigenetic regulation of gene expression (PMID: 29030101). A 2025 review consolidates the picture: 16 genome-wide significant variants and 32 epigenome-wide significant loci, with implicated genes falling into two functional groups — epithelial barrier function (FLG, SERPINB7) and immune function (HLA, IL4) (PMID: 39698764):

"Identified genes for food allergy are mainly involved in epithelial barrier function (e.g., FLG, SERPINB7) and immune function (e.g., HLA, IL4)."

Gene/ontology annotations: FLG (HGNC:3748), IL4 (HGNC:6014), IL13 (HGNC:5973), HLA-DQ/DR region, SERPINB7 (HGNC:8951), C11orf30/EMSY (HGNC:18071). Inheritance is multifactorial/polygenic (MONDO category: Complex). Evidence source: human GWAS.

Finding 2 — Early oral introduction prevents food allergy (LEAP/EAT): a primary-prevention paradigm shift

The LEAP randomized controlled trial (n=640 high-risk infants) demonstrated that early, sustained peanut consumption from infancy to age 5 prevents peanut allergy, and the protective effect persists to 12 years of age (144 months): peanut allergy was 15.4% in the original avoidance group vs 4.4% in the consumption group (P<0.001) (PMID: 38804779):

"At age 144 months, peanut allergy remained significantly more prevalent in participants in the original peanut avoidance group than in the original peanut consumption group (15.4% [38 of 246 participants] vs. 4.4% [11 of 251 participants]; P<0.001)."

A pooled intention-to-treat analysis of LEAP + EAT showed a 75% reduction in peanut allergy (p<.0001) among children randomized to early peanut consumption, with earlier introduction more effective (PMID: 36435990). Modeling estimated that a 77% population-level reduction in peanut allergy could be achieved by introducing peanut at 4 months (with eczema) / 6 months (without eczema), with the benefit diminishing for each month of delay (PMID: 36521802). Meta-analyses provide high-certainty evidence for peanut and egg (PMID: 41967460).

Analysis	Population	Effect	PMID
LEAP 12-yr follow-up	497 high-risk	15.4% vs 4.4% peanut allergy (P<0.001)	38804779
LEAP+EAT pooled ITT	High-risk + general	75% reduction (p<.0001)	36435990
Population model	All infants	77% reduction if introduced early	36521802
Meta-analysis	Multiple RCTs	High-certainty for peanut & egg	41967460

Mechanistic basis — the dual-allergen-exposure hypothesis: cutaneous exposure through an inflamed/disrupted skin barrier (e.g., atopic dermatitis) promotes sensitization, whereas early oral intake induces tolerance (PMID: 38740132, PMID: 41967460). Evidence source: human RCT + modeling.

Finding 3 — Pathophysiology: IgE-mediated type-2 immune cascade with mast-cell degranulation

Experimental food allergy demonstrates the causal chain. Allergen is taken up across the GI epithelium (facilitated when IgE–antigen complexes bind CD23 on epithelial cells) → pathogenic Th2 lymphocytes are activated (IL-4, IL-5, IL-13) → B cells class-switch to allergen-specific IgE → IgE binds FcεRI on mast cells and basophils → re-exposure cross-links surface IgE → mast-cell/basophil degranulation (histamine, mast cell protease MMCP-1) → anaphylaxis and local GI manifestations (PMID: 19079331):

"antigen uptake can be facilitated by immunoglobulin-E (IgE)-antigen complexes binding to CD23 on the epithelial cell surface. Studies on systemic anaphylaxis or local gastrointestinal manifestations of food allergy in mice have highlighted the contribution of IgE, mast cells, and pathogenic Th2 lymphocytes in experimental food allergy."

In mouse models, ovalbumin-specific serum IgE correlates with jejunal MMCP-1+ mast-cell density and predicts diarrhea, accompanied by increased IL-4/IL-6 (PMID: 19450258). Mast-cell-deficient W/Wv mice and IL-4/IL-10 neutralization studies confirm the dependence of the response on mast cells and Th2 cytokines (PMID: 12951468, PMID: 9003216). Evidence source: in vitro + model organism + human.

GO/CL ontology suggestions: GO:0016068 (type I hypersensitivity), GO:0043303 (mast cell degranulation), GO:0002639 (positive regulation of immunoglobulin production), GO:0042092 (type 2 immune response); CL:0000097 (mast cell), CL:0000767 (basophil), CL:0000546 (T-helper 2 cell), CL:0000236 (B cell). CHEBI: histamine (CHEBI:18295).

Finding 4 — Treatment: avoidance + epinephrine; OIT and omalizumab are disease-modifying

Intramuscular adrenaline (epinephrine) is the only life-saving treatment for food-induced anaphylaxis but is frequently delayed or underused; patients should carry autoinjectors (PMID: 40719286, PMID: 42262574):

"Intramuscular adrenaline continues to be the primary treatment, yet its administration is often delayed or insufficiently used."

Oral immunotherapy (OIT) achieves desensitization (e.g., sesame OIT ~85–97%) with mostly mild-to-moderate adverse events (PMID: 42808451); earlier initiation of cow's-milk OIT (<24 months) is associated with fewer severe reactions and no maintenance-phase anaphylaxis (PMID: 41616970). Omalizumab (anti-IgE monoclonal) raises reaction thresholds and improves OIT tolerability; in the OUtMATCH trial, post-omalizumab dietary consumption success reached 61–70% for milk/egg/wheat vs 38–56% for peanut/tree nuts (PMID: 40447195):

"greater success was observed for milk, egg, or wheat (61%-70%) than for peanut or tree nuts (38%-56%)"

Omalizumab monotherapy is now FDA-approved for food allergy.

NCIT treatment terms: Epinephrine (NCIT:C377), Omalizumab (NCIT:C2175), immunotherapy (NCIT:C15299), antihistamine (NCIT:C265), corticosteroid (NCIT:C2271). Evidence source: human clinical trials + reviews.

Finding 5 — Substantial psychosocial burden and reduced quality of life

Food allergy imposes measurable psychological and quality-of-life costs on patients and caregivers. Mothers of children with food allergy had significantly higher state anxiety (STAI-S, P<0.001) and caregiver burden (Zarit, P<0.001) and lower quality of life (EUROHIS-QOL, P=0.009) than controls; cow's-milk protein allergy specifically increased trait anxiety (P=0.035) (PMID: 40923420):

"Mothers in the FA group had significantly higher state anxiety (STAI-S) (P < 0.001) and ZCBS scores (P < 0.001) compared to controls."

In a national US sample (N=5,940 food-allergy households), 69.9% screened at-risk for food insecurity, and FA-related anxiety was the most common psychosocial experience (25.4%/30.1% of children/adults), higher among food-insecure households (p<.0001) (PMID: 38288585):

"FA-related anxiety was the most common (25.4%/30.1% of children/adults)"

Disease-specific instruments include the Food Allergy Quality of Life Questionnaire (FAQLQ) and Food Allergy Independent Measure (FAIM) (PMID: 37695230, PMID: 38288585). Evidence source: human cross-sectional/survey.

Finding 6 — Gut dysbiosis and reduced short-chain fatty acids: the gene-environment axis

Reduced gut bacterial diversity and abundance are epidemiologically associated with food allergy. Mechanistically, microbial short-chain fatty acids (SCFAs) steer CD4 T-cell differentiation toward anergic regulatory T cells (Treg, Foxp3+) versus allergic Th2 responses, acting through GPR41/GPR43/GPR109a receptors and histone-deacetylase inhibition (PMID: 39571752):

"T-cell differentiation poses an opportunity to direct the immune cells towards an anergic regulatory T cell (Treg) or allergic T helper 2 (Th2) response."

Early-life microbial exposures — particularly rural/farming environments — may protect against food allergy by stimulating innate immune pathways and shaping the gut microbiome, while air pollutants (PM, NO2), synthetic barrier-disrupting chemicals, and ultra-processed foods increase risk (PMID: 42670723):

"Early-life microbial exposures, especially those associated with rural and farming environments, may protect against food allergies by stimulating innate immune pathways and shaping the gut microbiome."

Probiotic evidence is inconclusive overall but more promising in cow's-milk protein allergy (PMID: 39571752). CHEBI: short-chain fatty acid (CHEBI:26666), butyrate (CHEBI:17968). CL: CL:0000815 (regulatory T cell). Evidence source: human epidemiology + mechanistic review.

Finding 7 — Epidemiology: ~8% of children / ~2% of adults, rising; three immunologic subtypes

Food-allergic conditions affect as many as 8% of young children and 2% of adults in Western countries, with rising prevalence (PMID: 39257598):

"Food allergic (FA) conditions have been classified as immunoglobulin E (IgE) and non-IgE-mediated reactions that affect as many as 8% of young children and 2% of adults in Western countries, and their prevalence seems to be rising."

A systematic review/meta-analysis of US pediatric data showed prevalence rose from 5.6% (2012) to 6.6% (2018) — a 1.6 percentage-point increase per decade (95% CI 0.5–2.7) — with stabilization between 2021 (7.9%) and 2024 (7.2%); the largest increase was among 10–17-year-olds, with no difference by race/ethnicity (PMID: 42887634):

"FA increased from 5.6% in 2012 to 6.6% in 2018 (1.6 percentage-point increase per decade; 95% CI: 0.5-2.7), with stabilization between 2021 (7.9%) and 2024 (7.2%)."

Classification spans three types: IgE-mediated FA (Th2/IgE basis), non-IgE-mediated FA (e.g., FPIES, food protein-induced allergic proctocolitis), and mixed IgE/non-IgE (eosinophilic esophagitis). Regional triggers differ: peanuts/tree nuts predominate in Western countries, hen's egg/cow's milk in East Asia, seafood in Southeast Asia (PMID: 40719286). Evidence source: human epidemiology.

Finding 8 — Prognosis: usually non-fatal; rare fatal anaphylaxis with identifiable risk factors

Anaphylaxis case-fatality is estimated at 0.65–2% in children; food is the main trigger (cow's milk, peanuts, tree nuts); mucocutaneous signs occur in >90% of cases and death is usually secondary to laryngeal edema (seen in 40–50%). Risk factors for severe/fatal reactions include personal asthma history, peanut/tree-nut allergy, and adolescence (PMID: 33236416):

"Anaphylaxis fatality rate is estimated to be 0.65% to 2%. Food is the main anaphylaxis trigger in children, notably cow's milk, peanuts, and tree nuts. Mucocutaneous manifestations are observed in more than 90% of cases"

A systematic review of 32 studies found that young adults with asthma and known peanut/tree-nut allergy are at higher risk of fatal anaphylaxis; delayed adrenaline injection is associated with fatal outcomes, though timely adrenaline alone may be insufficient; cofactors include alcohol, exercise, medications, and mast cell disorders (PMID: 30288817). Many IgE-mediated childhood allergies (milk, egg) resolve with age, whereas peanut/tree-nut/seafood allergies more often persist; SPT and sIgE thresholds imperfectly predict resolution (PMID: 24132133). Evidence source: human epidemiology + systematic review.

Finding 9 — Animal models: adjuvant-based and adjuvant-free (epicutaneous) mouse models

Mouse models (e.g., Balb/c, C3H/HeJ) sensitized to ovalbumin or peanut — orally with mucosal adjuvants such as cholera toxin, or epicutaneously (adjuvant-free) — then orally challenged, reproduce allergen-specific IgE, intestinal mast-cell activation (MMCP-1), Th2 cytokines, and systemic anaphylaxis (PMID: 19079331, PMID: 19450258). Mast-cell-deficient W/Wv mice and IL-4/IL-10 neutralization establish mast-cell and Th2-cytokine dependence (PMID: 12951468, PMID: 9003216). In C3H/HeJ mice, epicutaneous immunotherapy (OVA-Viaskin patches) induced sustained protection against anaphylaxis via gastrointestinal-homing LAP+/Treg cells, demonstrating skin–gut immune crosstalk and a tissue-specific GI Treg deficiency in allergic mice (PMID: 27417020):

"epicutaneous application of antigen generated a population of gastrointestinal-homing LAP"

Phenotype recapitulation: good for IgE, mast-cell activation, Th2 cytokines, and anaphylaxis; limitations: adjuvants are artificial, and murine oral tolerance differs from human timing. NCBI Taxon: Mus musculus (10090). Evidence source: model organism.

Finding 10 — Natural (spontaneous) food allergy in companion animals

Adverse food reactions occur naturally in dogs and cats, affecting mainly the integument and GI tract. In dogs, pruritus of distal limbs/face/ears/ventrum predominates, presenting as recurrent bacterial skin infections, otitis externa, and atopic dermatitis; four breeds (German shepherds, West Highland white terriers, Labrador and golden retrievers) account for ~40% of affected dogs, with onset by 6–12 months in 22–38% (PMID: 31072328):

"Four breeds (German shepherd dogs, West Highland white terriers, Labrador and golden retrievers) accounted for about 40% of affected dogs. Most dogs diagnosed with a CAFR were pruritic"

Non-cutaneous signs include GI (diarrhea, vomiting), conjunctivitis, and even anaphylaxis (PMID: 30419909). As in humans, elimination diet followed by oral food challenge is the diagnostic gold standard (PMID: 29871756, PMID: 32448251):

"An elimination diet over several weeks using a protein source and a carbohydrate source previously not fed is still the diagnostic tool of choice."

NCBI Taxon: Canis lupus familiaris (9615), Felis catus (9685). Evidence source: veterinary clinical.

Finding 11 — Phenotype spectrum: multi-system disease, urticaria/angioedema most frequent

Food allergy is a multi-system disease. In an anaphylaxis cohort, organ involvement was cutaneous 95.7%, cardiovascular 76.8%, respiratory 74.6%; the most common manifestations were urticaria (81.9%), dyspnea (71.3%), and angioedema (69.4%); 2.2% had biphasic reactions (PMID: 18254479):

"The organs most frequently involved in the anaphylaxis were cutaneous (95.7%), cardiovascular (76.8%), and respiratory (74.6%). The most common manifestations were dyspnea (71.3%), urticaria (81.9%), and angioedema (69.4%)."

In childhood food allergy the most common skin manifestations were angioedema (48%), urticaria (31%), and atopic dermatitis (21%) (PMID: 9252873). Across food anaphylaxis, mucocutaneous signs occur in >90% and laryngeal edema in 40–50% (PMID: 33236416).

Phenotype	Frequency	HPO term
Urticaria	81.9% (anaphylaxis); 31% (childhood)	HP:0001025
Angioedema	69.4%; 48% (childhood)	HP:0100665
Dyspnea/respiratory	71.3–74.6%	HP:0002094
Cardiovascular/hypotension	76.8%	HP:0002615 / HP:0001635
Atopic dermatitis/eczema	21% (childhood)	HP:0001047
Anaphylaxis	—	HP:0100845
Diarrhea/vomiting (GI)	—	HP:0002014 / HP:0002017
Laryngeal edema	40–50%	HP:0012027

Evidence source: human clinical cohorts.

Finding 12 — Epigenetics: DNA-methylation signatures distinguish clinical allergy from sensitization

A machine-learning study on DNA-methylation (DNAm) data narrowed 405,000+ CpGs to an 18-CpG signature mapping to 13 genes (many immune-associated; 7 previously linked to food allergy) that achieved high classification accuracy distinguishing food-allergic from merely sensitized individuals — addressing the <50% accuracy of standard tests and the reliance on oral food challenges (PMID: 31216310):

"The 18-CpG signature mapped to 13 genes, on which biological insights were collected. Notably, many of the FA-discriminating genes found in this study were strongly associated with the immune system, and seven of the 13 genes were previously associated with FA."

A 2025 review reports 32 epigenome-wide significant loci in food allergy (PMID: 39698764). This positions epigenetic marks as both a mechanism and a candidate diagnostic. Evidence source: human computational/epigenomics.

Finding 13 — Alpha-gal syndrome: a tick-bite-induced, delayed, adult-onset red-meat allergy

Alpha-gal syndrome (AGS) is a delayed IgE-mediated food allergy to galactose-α-1,3-galactose (α-Gal), a carbohydrate epitope ubiquitously expressed in non-primate mammalian tissues. Sensitization follows tick bites and produces delayed (often 2–6 h) reactions to red meat and mammalian products (PMID: 42571940, PMID: 42808634):

"α-Gal has emerged as the causative antigen of alpha-gal syndrome (AGS), a delayed IgE-mediated food allergy to mammalian-derived products, including red meat."

"Alpha-gal syndrome (AGS) is an emerging red meat allergy, IgE-mediated, with delayed reactions to a carbohydrate derived from mammals: α-gal (galactose-α-1,3-galactose). Sensitization follows a tick bite."

α-Gal epitopes are thermostable, so conventional cooking may not reduce allergenicity, and AGS epidemiology is shaped by tick distribution with likely under-diagnosis (PMID: 42571940). Sensitized individuals show elevated innate-immune markers and reduced regulatory cytokines (IL-10, IL-35) (PMID: 42877672). AGS is an important example of an environmentally triggered, carbohydrate-directed, adult-onset food allergy that departs from the classic protein-sensitization, childhood-onset paradigm. CHEBI: galactose-α-1,3-galactose. Evidence source: human clinical/review.

Finding 14 — Food allergy–eosinophilic esophagitis continuum: antigen exposure shapes immune phenotype

IgE-mediated food allergy and eosinophilic esophagitis (EoE) are interconnected manifestations on a continuum determined by antigen exposure patterns, dose, and chronicity. Among children with IgE-mediated food allergy, EoE prevalence is ~4.7% (nearly 100-fold higher than the general population), and during oral immunotherapy confirmed EoE develops in 1–10% of participants. Mechanistically, antigen avoidance favors IgE-mediated responses via T follicular helper cells, whereas sustained exposure promotes a shift toward eosinophilic/EoE-type inflammation (PMID: 42575621):

"Among children with IgE-mediated food allergy, EoE prevalence is nearly 100-fold higher than the general population at 4.7%. During oral immunotherapy, gastrointestinal symptoms are common, with confirmed EoE developing in 1% to 10% of participants."

This finding clarifies a key safety consideration for OIT and links the IgE-mediated and mixed subtypes mechanistically. CL: CL:0000771 (eosinophil); UBERON: UBERON:0001043 (esophagus). Evidence source: human clinical/review.

Mechanistic Model / Interpretation

Ordered causal chain (initiating lesion → clinical manifestation)

1. GENETIC + ENVIRONMENTAL PREDISPOSITION
   Barrier genes (FLG, SERPINB7) + immune genes (HLA, IL4/IL13, C11orf30/EMSY)
   + exposome (pollution, dysbiosis/low SCFA, timing of allergen exposure)
│  leads to
▼
2. EPITHELIAL BARRIER DYSFUNCTION
   Impaired skin and/or gut barrier allows allergen penetration
   (CD23-mediated transepithelial uptake in the gut)
│  results in
▼
3. BRANCH POINT — SITE & TIMING OF FIRST EXPOSURE (dual-allergen-exposure hypothesis)
   ├── Cutaneous exposure through INFLAMED skin → SENSITIZATION  ──┐
   └── Early ORAL exposure through HEALTHY gut   → TOLERANCE (Treg) │ [protective; LEAP/EAT]
                                                            ▼
4. TH2 POLARIZATION  (sensitization pathway)
   Dendritic cells present allergen → pathogenic Th2 cells (IL-4, IL-5, IL-13)
   [Low SCFA tips the Treg/Th2 balance toward Th2 — inferred from models]
│  drives
▼
5. IgE CLASS-SWITCH
   B cells produce allergen-specific IgE
│  which binds
▼
6. EFFECTOR-CELL ARMING
   IgE occupies FcεRI on mast cells and basophils
│  then on RE-EXPOSURE
▼
7. DEGRANULATION
   Allergen cross-links surface IgE → histamine, tryptase, MMCP-1 release
│  causing
▼
8. CLINICAL MANIFESTATION (multi-system)
   Cutaneous (urticaria 82%, angioedema 69%), respiratory (dyspnea 71%),
   cardiovascular (hypotension 77%), GI → ANAPHYLAXIS (fatality 0.65–2%)

   BRANCH (chronic sustained exposure): shift toward EOSINOPHILIC inflammation
   → eosinophilic esophagitis (EoE), the "mixed" phenotype

Upstream vs downstream. Upstream drivers are genetic barrier/immune variants and environmental/exposome factors (steps 1–3). The Th2→IgE axis (steps 4–6) is the central, intermediate mechanism — the node targeted by both omalizumab (sequesters IgE) and OIT (reprograms the T-cell/antibody response toward IgG4/Treg). Downstream (steps 7–8) is effector-cell degranulation and the clinical syndrome — the node targeted by adrenaline.

Cell types involved: epithelial cells (CL:0000066), dendritic cells (CL:0000451), Th2 cells (CL:0000546), B cells (CL:0000236), mast cells (CL:0000097), basophils (CL:0000767), regulatory T cells (CL:0000815), eosinophils (CL:0000771).

Anatomical structures (UBERON): skin (UBERON:0002097), gastrointestinal tract / small intestine–jejunum (UBERON:0001052 / UBERON:0002115), esophagus (UBERON:0001043), respiratory tract / larynx (UBERON:0001004 / UBERON:0001737), cardiovascular system (UBERON:0004535). Body systems: integumentary, digestive, respiratory, cardiovascular, immune.

Therapeutic logic mapped onto the chain

Intervention	Mechanistic node targeted	Effect
Early oral introduction (LEAP/EAT)	Step 3 branch point	Diverts to tolerance; 77% population reduction
Allergen avoidance	Step 7 (prevents cross-linking)	Prevents reactions (but may favor IgE/EoE branch)
Oral immunotherapy (OIT)	Steps 4–6 (reprograms T/B response)	Desensitization ~85–97% (sesame)
Omalizumab (anti-IgE)	Step 6 (sequesters free IgE)	Raises thresholds; 38–70% consumption success
Adrenaline (epinephrine)	Step 8 (reverses effector physiology)	Life-saving acute rescue

Evidence Base

PMID	Title (abbrev.)	Supports finding	Evidence type
29051540	SERPINB GWAS of food allergy	F1 (core susceptibility loci)	Human GWAS
29030101	Multi-population peanut GWAS; C11orf30/EMSY	F1	Human GWAS/meta
39698764	FA genetics & epigenetics review	F1, F12	Review
38804779	LEAP 12-yr follow-up	F2	Human RCT
36435990	Pooled LEAP+EAT causal inference	F2	Human RCT pooled
36521802	Window of opportunity model	F2	Modeling
41967460	Prevention by early introduction	F2	Meta-analysis
19079331	Immunophysiology of experimental FA	F3, F9	Model organism
19450258	IgE–MMCP-1 in jejunum	F3, F9	Model organism
12951468	W/Wv mast-cell-deficient mice	F3, F9	Model organism
9003216	Murine onset model, IL-4/IL-10	F3, F9	Model organism
40719286	Epidemiology & management of anaphylaxis	F4, F7	Review
40447195	OUtMATCH: foods after omalizumab	F4	Human RCT
42808451	Sesame immunotherapy review	F4	Systematic review
41616970	Cow's-milk OIT timing	F4	Human cohort
40923420	Maternal psychological effects	F5	Human cross-sectional
38288585	Food insecurity & psychosocial burden	F5	Human survey
37695230	QoL, FAQLQ, caregiver burden	F5	Human cross-sectional
39571752	Gut dysbiosis & probiotics	F6	Review
42670723	External exposome & FA	F6	Review
39257598	IgE & non-IgE mechanisms review	F7	Review
42887634	US pediatric FA temporal trends	F7	Meta-analysis
33236416	Anaphylaxis in children	F8, F11	Review
30288817	Food-induced fatal anaphylaxis	F8	Systematic review
24132133	Natural history; SPT/sIgE prediction	F8	Systematic review
27417020	Epicutaneous IT, GI LAP+ Tregs	F9	Model organism
31072328	Canine/feline AFR signalment	F10	Veterinary
30419909	Non-cutaneous AFR in pets	F10	Veterinary
29871756	AFR pathogenesis/diagnosis	F10	Veterinary review
32448251	Time to flare after OFC (pets)	F10	Veterinary
18254479	Anaphylaxis features in Korea	F11	Human cohort
9252873	Childhood FA skin manifestations	F11	Human cohort
31216310	ML epigenetic biomarker (18-CpG)	F12	Human computational
42571940	Alpha-gal syndrome mechanisms	F13	Review
42808634	Alpha-gal syndrome overview	F13	Review
42877672	Alpha-gal immunologic comparison	F13	Human cohort
42575621	FA–EoE continuum	F14	Review
38740132	Cutaneous allergen exposure in AD	F2 (dual-allergen)	Review

Diagnostics (cross-cutting). The diagnostic standard is oral food challenge (OFC) — skin prick tests and serum-specific IgE are sensitive but poorly specific, frequently identifying clinically irrelevant sensitization (PMID: 42358594, PMID: 42545935). Component-resolved diagnostics (e.g., Ara h 2 for peanut, casein for milk, ovomucoid for egg) improve risk stratification; casein-specific IgE ≥2.55 kUA/L predicted milk-OFC positivity with AUC 0.878 (PMID: 42451187). Emerging functional assays include the basophil activation test (BAT) and mast cell activation test (MAT) (PMID: 42358594). Food-specific IgG testing is not a validated diagnostic for IgE-mediated allergy (PMID: 42818614). Note that skin prick testing itself can rarely provoke generalized reactions in infants (PMID: 11152165).

Key identifiers. MONDO:0700226; MeSH D005512 (Food Hypersensitivity); ICD-10 T78.0–T78.1 / Z91.01–Z91.018; ICD-11 4A85. Synonyms: IgE-mediated food allergy, food hypersensitivity, allergic disease from food material. Information is derived from aggregated disease-level resources (GWAS cohorts, registries, RCTs, reviews) rather than a single EHR patient series.

Limitations and Knowledge Gaps

No single causal gene. The research template field "causal gene(s): not recorded" is correct — food allergy is polygenic. GWAS to date explain only a modest fraction of heritability; effect sizes at individual loci are small, and most loci are regulatory rather than coding. Penetrance of susceptibility alleles is low and strongly environment-dependent.
Mechanistic evidence is weighted toward murine models. The core IgE/mast-cell/Th2 cascade (F3, F9) is best demonstrated in mice using artificial adjuvants; the exact triggers of human sensitization and the quantitative role of SCFA/microbiome in humans remain inferential rather than proven causally.
Diagnostic imprecision. SPT and sIgE have low specificity; OFC — the gold standard — is resource-intensive and carries reaction risk. Epigenetic (DNAm) and functional (BAT/MAT) biomarkers are promising but not yet in routine clinical use.
Subtype heterogeneity. Non-IgE-mediated forms (FPIES, proctocolitis) and the mixed EoE phenotype are mechanistically distinct and less well characterized than classic IgE-mediated allergy; this report is weighted toward IgE-mediated disease.
Prevention generalizability. High-certainty early-introduction evidence exists for peanut and egg; data for other allergens (milk, tree nuts, seafood) are weaker, and optimal dose/duration are undefined.
Treatment durability. OIT achieves desensitization but sustained unresponsiveness (true tolerance after stopping) is less certain; omalizumab requires ongoing administration. Long-term outcomes of combination strategies are still emerging.
Epidemiologic measurement. Much prevalence data is self-reported, likely over-estimating true (OFC-confirmed) food allergy; regional/ethnic variation is incompletely mapped.

Proposed Follow-up Experiments / Actions

Polygenic risk score (PRS) development and validation. Combine the 16 GWAS loci into a PRS and test whether it predicts (a) which sensitized children have clinical reactivity and (b) who benefits most from early introduction — enabling risk-stratified prevention. (Builds on F1, F2.)
Prospective human microbiome–SCFA intervention trial. Test whether butyrate/SCFA supplementation or defined probiotic consortia (beyond cow's-milk-allergy settings) shift the Treg/Th2 balance and prevent or treat food allergy, with stool metabolomics as a mechanistic readout. (F6.)
Validate the 18-CpG DNA-methylation signature prospectively against OFC outcomes in an independent multi-ethnic cohort, and benchmark it head-to-head against component-resolved IgE and BAT to reduce reliance on OFC. (F12.)
Define the EoE-risk window during OIT. Prospectively monitor esophageal eosinophilia (symptom-triggered endoscopy or non-invasive biomarkers) across OIT protocols to quantify dose/chronicity thresholds that tip patients into the eosinophilic branch. (F14.)
Extend early-introduction RCTs to non-peanut/egg allergens (tree nuts, sesame, seafood) with harmonized dosing to generate high-certainty evidence beyond peanut and egg. (F2.)
Characterize alpha-gal syndrome epidemiology and mechanism with tick-exposure cohorts, mapping geographic tick distribution to AGS incidence and dissecting the innate/regulatory cytokine imbalance (IL-10, IL-35) as therapeutic targets. (F13.)
Comparative/One-Health studies leveraging spontaneous canine and feline food allergy as a natural large-animal model to test tolerance-inducing interventions before human translation. (F10.)

Report compiled from a 5-iteration autonomous investigation: 14 confirmed findings, 58 papers reviewed. Evidence types span human GWAS/RCT/cohort/survey, model organism, veterinary clinical, and computational studies.

Artifacts

Reference Validation

Checked with linkml-reference-validator 0.3.0.

Outcome	Count
References checked	44
Resolved	44
Unresolved (possible confabulation)	0
Unverifiable	0
References weighed for topical relevance	44
On topic	36
Off topic	0

All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Outcome	Count
Terms checked	43
Resolved	37
Unresolved (possible confabulation)	0
Obsolete	1
Unverifiable	5
Terms whose name was checked	14
Terms named correctly	11
Terms named as a different term	3

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

HP:0001025 (1 mention) - the report calls it "81.9% (anaphylaxis); 31% (childhood)"; HP calls it Urticaria
HP:0100665 (1 mention) - the report calls it "69.4%; 48% (childhood)"; HP calls it Angioedema
HP:0001047 (1 mention) - the report calls it "21% (childhood)"; HP calls it Atopic dermatitis

Obsolete terms

These terms are real but deprecated. Citing one is not a fabrication; it does mean the report is naming something the ontology has retired:

NCIT:C2175 (Gene-Vector Complex) (1 mention)

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Diagnosis

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References & Deep Research

Deep Research

Food Allergy (MONDO:0700226) — Comprehensive Disease Characteristics Report

Summary

Key Findings

Finding 1 — Food allergy is polygenic: barrier genes + type-2 immune genes

Finding 2 — Early oral introduction prevents food allergy (LEAP/EAT): a primary-prevention paradigm shift

Finding 3 — Pathophysiology: IgE-mediated type-2 immune cascade with mast-cell degranulation

Finding 4 — Treatment: avoidance + epinephrine; OIT and omalizumab are disease-modifying

Finding 5 — Substantial psychosocial burden and reduced quality of life

Finding 6 — Gut dysbiosis and reduced short-chain fatty acids: the gene-environment axis

Finding 7 — Epidemiology: ~8% of children / ~2% of adults, rising; three immunologic subtypes

Finding 8 — Prognosis: usually non-fatal; rare fatal anaphylaxis with identifiable risk factors

Finding 9 — Animal models: adjuvant-based and adjuvant-free (epicutaneous) mouse models

Finding 10 — Natural (spontaneous) food allergy in companion animals

Finding 11 — Phenotype spectrum: multi-system disease, urticaria/angioedema most frequent

Finding 12 — Epigenetics: DNA-methylation signatures distinguish clinical allergy from sensitization

Finding 13 — Alpha-gal syndrome: a tick-bite-induced, delayed, adult-onset red-meat allergy

Finding 14 — Food allergy–eosinophilic esophagitis continuum: antigen exposure shapes immune phenotype

Mechanistic Model / Interpretation

Ordered causal chain (initiating lesion → clinical manifestation)

Therapeutic logic mapped onto the chain

Evidence Base

Limitations and Knowledge Gaps

Proposed Follow-up Experiments / Actions

Artifacts

Reference Validation

Term Validation

Terms the report names something else

Obsolete terms