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Cross-provider research synthesis

Acute Lichenoid Pityriasis

MONDO:0024250 Curated 2026-07-04T00:00:00Z 9 harmonized findings
falcon · 39 citations openscientist · 41 citations
Concordant asserts the finding Partial supports a weaker/qualified form Contradictory conflicts with it Silent does not address it

Harmonized findings

Acute lichenoid pityriasis is synonymous with pityriasis lichenoides et varioliformis acuta (PLEVA) / Mucha-Habermann disease, the acute pole of the pityriasis lichenoides spectrum, presenting as recurrent crops of erythematous papulovesicular lesions that undergo necrosis/hemorrhagic crusting and can heal with varioliform scarring, with a rare severe febrile ulceronecrotic variant (FUMHD).

UNANIMOUS INTEGRATED
phenotypediagnosis
ProviderStanceScoreEvidence
falcon CONCORDANT 90% PLEVA is an uncommon inflammatory papulosquamous dermatosis characterized clinically by crops of erythematous papules/papulovesicles that may become necrotic/hemorrhagic and can heal with varioliform scarring, with recurrences over time.
Falcon defines acute lichenoid pityriasis as PLEVA and describes the papulovesicular, necrotic, varioliform-scarring, relapsing morphology.
DOI:10.70672/bcfbzp08, DOI:10.1111/bjd.18977
openscientist CONCORDANT 92% The disease exists on a clinical spectrum that includes chronic pityriasis lichenoides (PLC) at one end and the rare, potentially fatal febrile ulceronecrotic Mucha-Habermann disease (FUMHD) at the other.
OpenScientist gives the same PLEVA/Mucha-Habermann identity and explicitly frames the PLC-PLEVA-FUMHD spectrum.
PMID:8864599

PLEVA is a T-cell-mediated interface/lichenoid dermatitis in which cytotoxic T lymphocytes attack basal keratinocytes, producing keratinocyte necrosis and lymphocytic vasculitis; the predominant lesional infiltrate is characterized as CD8+ cytotoxic.

MAJORITY INTEGRATED
pathophysiology
ProviderStanceScoreEvidence
openscientist CONCORDANT 90% is a rare CD8+ cytotoxic T-lymphocyte-mediated inflammatory dermatosis of unknown etiology that primarily affects children and young adults.
OpenScientist asserts a specifically CD8+ cytotoxic T-lymphocyte-mediated mechanism directed at keratinocytes and dermal vasculature.
PMID:38973067
falcon PARTIAL 55% PLEVA lesions show interface/lichenoid dermatitis with epidermotropism in some cases, and PLEVA may represent a benign clonal or oligoclonal T-cell–driven process in a subset.
Falcon agrees on a T-cell-driven interface dermatitis but stops short of asserting CD8+ predominance — it reports a pediatric case with CD4+++ immunophenotype, so it supports the T-cell mechanism without endorsing the CD8-dominant characterization.
DOI:10.24875/bmhim.22000043

The leading etiologic hypothesis is that PLEVA is a hypersensitivity/immune reaction triggered by (but not proven to be caused by) infectious agents (e.g., streptococci, EBV, VZV, HIV, Toxoplasma), and less often drugs or vaccines; no specific cause is established.

UNANIMOUS INTEGRATED
pathophysiology
ProviderStanceScoreEvidence
falcon CONCORDANT 85% (not proven caused) by infections, drugs, or vaccines in some patients.
Falcon frames infections/drugs/vaccines as triggers rather than proven causes, matching the hypersensitivity-to-antigen hypothesis.
DOI:10.70672/bcfbzp08
openscientist CONCORDANT 85% The etiology of MH remains obscure, but it may be the result of a hypersensitivity reaction to an infectious agent
OpenScientist cites the classic hypersensitivity-to-infectious-agent hypothesis and lists the same temporally associated pathogens.
PMID:8864599

PLEVA has no identified causal gene and is not a Mendelian/monogenic disorder; T-cell receptor clonality is detected in a subset of cases but is not by itself diagnostic of lymphoma.

UNANIMOUS INTEGRATED
genetic_factordiagnosis
ProviderStanceScoreEvidence
falcon CONCORDANT 88% No causal genes or pathogenic germline variants were identified in the retrieved literature; PLEVA is generally treated as a complex inflammatory dermatosis rather than a monogenic disorder in these sources.
Falcon reports no causal genes and adds that TCR clonality is variably detected and not diagnostic of lymphoma by itself.
DOI:10.1007/s13671-013-0054-x
openscientist CONCORDANT 88% No causal genes have been identified for PLEVA.
OpenScientist states there is no causal gene and that TCR clonality (~50% of cases) does not necessarily indicate malignancy.
PMID:12203210

Diagnosis is clinicopathologic, with characteristic histopathology showing interface/lichenoid dermatitis, necrotic/dyskeratotic keratinocytes, lymphocytic vasculitis, and erythrocyte extravasation.

UNANIMOUS INTEGRATED
diagnosis
ProviderStanceScoreEvidence
openscientist CONCORDANT 90% Histopathologically, PLEVA is defined by interface dermatitis, lymphocytic vasculitis, necrotic keratinocytes, and perivascular CD8+ T-cell infiltrates with erythrocyte extravasation.
OpenScientist gives the histopathologic hallmark set and quantifies feature frequencies (necrotic keratinocytes 100%, vasculitis 100%).
PMID:31880634, PMID:17456915
falcon CONCORDANT 85% parakeratosis, spongiosis, lichenoid/interface dermatitis, dyskeratotic keratinocytes, erythrocyte extravasation, focal epidermotropism, epidermal necrosis, hemorrhagic crusting/ulceration
Falcon lists the same clinicopathologic findings and notes a case with lymphocytic vasculitis and focal epidermal necrosis.
DOI:10.70672/bcfbzp08

PLEVA generally follows a benign, self-limited or relapsing course, with only a small minority (roughly 5%) progressing to cutaneous T-cell lymphoma (mycosis fungoides) over years of prolonged disease.

UNANIMOUS INTEGRATED
prognosis
ProviderStanceScoreEvidence
openscientist CONCORDANT 90% Long-term follow-up studies involving up to 242 patients with median 9.9-year follow-up demonstrate no established progression to cutaneous T-cell lymphoma (CTCL), though approximately 5% of patients with prolonged clinical courses may develop mycosis fungoides (MF) over 3-11 years.
OpenScientist reports a benign natural history with a low (~5%) MF progression rate from a large long-term cohort.
PMID:41420620, PMID:29210716
falcon CONCORDANT 80% PLEVA is generally benign/self-limited but can be relapsing.
Falcon agrees the course is benign/relapsing and separately reports a Thai pediatric cohort in which 1/43 was later diagnosed as mycosis fungoides.
DOI:10.35755/jmedassocthai.2025.5.377-383-02606

The febrile ulceronecrotic Mucha-Habermann disease (FUMHD) variant is a life-threatening form with systemic involvement (sepsis, cardiopulmonary, CNS) and substantial mortality that is markedly higher in adults than children.

MAJORITY INTEGRATED
prognosisphenotype
ProviderStanceScoreEvidence
openscientist CONCORDANT 90% The severe FUMHD variant carries an overall mortality of 12%, with adults at significantly higher risk (20%) compared to children (2%).
OpenScientist quantifies FUMHD mortality (12% overall; adults 20% vs children 2%) with age/sepsis/systemic-involvement risk factors and a risk score.
PMID:34287852
falcon PARTIAL 50% Severe FUMHD can present with mucosal involvement, high fever, and systemic complications (e.g., sepsis, cardiomyopathy, pulmonary involvement).
Falcon describes FUMHD as a severe systemic variant but does not quantify mortality or the adult-vs-child mortality stratification.
DOI:10.70672/bcfbzp08

Treatment is supportive and not RCT-backed; phototherapy (especially narrowband UVB) achieves the highest complete-remission rates and is preferred, with oral antibiotics (erythromycin) commonly used first-line in children.

UNANIMOUS INTEGRATED
treatment
ProviderStanceScoreEvidence
falcon CONCORDANT 88% had the highest proportion of complete remissions; NB-UVB often recommended first-line.
Falcon's appraisal of the treatment literature ranks phototherapy highest for complete remission and flags NB-UVB first-line with erythromycin/methotrexate.
DOI:10.1111/bjd.18977, DOI:10.1007/s40257-016-0216-2
openscientist CONCORDANT 88% Of these treatments, phototherapy led to complete remission in the highest proportion of patients
OpenScientist reports phototherapy as the most effective modality (NB-UVB 73% clearance, 0% recurrence) with erythromycin first-line in children.
PMID:32112390, PMID:27502793

PLEVA affects mainly children and young adults; sex distribution is age-dependent, with a male predominance in children that reverses to a female predominance in adults.

MAJORITY LEAD
epidemiology
ProviderStanceScoreEvidence
openscientist CONCORDANT 90% The results show a male-to-female ratio of 1.7:1 for pediatric patients and 0.6:1 for adults, with a higher incidence of male patients among children (p < 0.01)
OpenScientist documents the age-dependent sex reversal (M:F 1.7:1 in children vs 0.6:1 in adults) from a 242-patient cohort.
PMID:41420620
falcon PARTIAL 45% and notes slight male predominance and typical onset in late childhood/young adulthood.
Falcon reports only an overall slight male predominance and childhood/young-adult onset; it does not describe the adult female-predominant reversal, so it supports the demographics partially.
DOI:10.1111/bjd.18977

Narrative

Overview

Both providers characterize acute lichenoid pityriasis as pityriasis lichenoides et varioliformis acuta (PLEVA / Mucha-Habermann disease), the acute pole of the pityriasis lichenoides spectrum, whose severe end is febrile ulceronecrotic Mucha-Habermann disease (FUMHD). Falcon used the pathophysiology-focused template and is mechanism- and evidence-appraisal oriented; OpenScientist used the broad disease-characteristics template and is more clinical and quantitative, adding demographics, FUMHD mortality, and treatment-outcome numbers.

Agreement

The reports converge on the core disease model: a T-cell-mediated interface/lichenoid dermatitis driven by an immune hypersensitivity reaction to infectious (or occasionally drug/vaccine) triggers that are associated but not proven causal; characteristic clinicopathology (interface dermatitis, necrotic keratinocytes, lymphocytic vasculitis, erythrocyte extravasation); the absence of any causal gene and the non-diagnostic nature of TCR clonality; a benign, self-limited/relapsing natural history with only a small minority progressing to mycosis fungoides; and phototherapy (NB-UVB) as the most effective modality with erythromycin first-line in children in the absence of any RCT.

Divergence

Divergence is chiefly coverage and quantification, not conflict. OpenScientist asserts a specifically CD8+ cytotoxic T-cell predominance, whereas Falcon frames the infiltrate more agnostically as T-cell-driven and even reports one pediatric case with a CD4+++ immunophenotype. OpenScientist quantifies FUMHD mortality (12% overall; adults 20% vs children 2%) and an age-dependent sex reversal (M:F 1.7:1 in children vs 0.6:1 in adults) that Falcon does not capture; Falcon reports only an overall slight male predominance and describes FUMHD severity without mortality figures. OpenScientist also confidently assigns disease identifiers (MONDO:0024250, ICD-10 L41.0), while Falcon states the identifiers were not retrievable from its evidence base — a coverage gap rather than a contradiction.

Integration

The concordant mechanistic and clinical claims are suitable for promotion into kb/disorders/Acute_Lichenoid_Pityriasis.yaml: the T-cell interface-dermatitis pathophysiology with keratinocyte necrosis and lymphocytic vasculitis, the infectious-hypersensitivity trigger framing, the characteristic histopathology, the no-causal-gene/clonality-not-diagnostic genetics, the benign course with rare MF progression, the FUMHD severe-variant prognosis, and the phototherapy/ erythromycin treatment hierarchy.

Not integrated (leads)

The age-dependent sex-ratio reversal is retained as a research lead pending reconciliation of the single-cohort figure with Falcon's overall male predominance. Provider-specific quantitative details (exact clearance/recurrence percentages, FUMHD risk-score coefficients, per-pathogen case reports, COVID-19 vaccine temporal associations) are kept as leads rather than promoted verbatim, to be re-verified against fetched abstracts before entering the disorder YAML.

Cross-provider synthesis comparing falcon (Edison Scientific Literature, pathophysiology template) and openscientist (autonomous, disease-characteristics template). The two reports share no PMID/DOI overlap (Falcon cites DOIs; OpenScientist cites PMIDs) but agree substantively on mechanism, diagnosis, genetics, prognosis, and treatment. No direct contradictions were found; divergence is coverage/quantification (CD8 predominance, FUMHD mortality, age-dependent sex reversal, disease identifiers). All best_matching_text values are verbatim substrings of the cited report files; literature evidence snippets are left to the main curation pipeline pending fetch-reference verification.