Class-to-Epidemiological-Group Mapping — autoimmune + genodermatosis

Status: 2026-04-20 — autoimmune and genodermatosis columns finalised for today's R-TF-028-* sub-analysis after a methodological review pass. The inclusion lists were tightened from the first draft to apply the "Inclusion principle" (below) with discipline: five borderline autoimmune classes (SJS/TEN, erythema multiforme, necrobiosis lipoidica, Sweet syndrome, pyoderma gangrenosum) were removed as immune-mediated but not classical autoimmune; five genodermatosis classes (café-au-lait spot, lymphatic malformation, the three developmental vascular malformation classes LC50/LC51/EF2Z) were removed as either signs rather than diseases or developmental/congenital rather than inherited. The five remaining group columns (inflammatory, malignant_or_pigmented, infectious, benign_neoplastic, other) are schema-present and zero-filled; they are populated in the next R-TF-028 update per the change-control plan. This file is the clinical-rationale record behind one-hot-mapping-matrix.csv.

Curation provenance: class inclusion/exclusion decisions were made by the internal clinical team (dermatology-trained clinical lead + quality lead) against the Inclusion principle below and the ICD-11 chapter organisation of each class. The finalised one-hot matrix will be shared with the ML engineering lead for propagation into the default V&V pipeline in the next release.

Scope

The model's output space has 346 validated ICD-11 categories (source: model_diagnosis_classes.csv for model version v27.5.1, one row per class; class index = row order, 0-indexed). This file assigns each relevant class to one or more epidemiological groups. Multi-group assignment is permitted (e.g., some vasculitides are both autoimmune and inflammatory). A class not assigned to any of the seven groups is left zero-filled across all seven columns — that is an acceptable state and indicates the class is not epidemiologically representative of any of the seven named groups.

Inclusion principle

A class is marked autoimmune if the disease is widely recognised as an antibody-mediated or T-cell-mediated autoimmune or auto-inflammatory disorder in standard dermatology references (Bolognia's Dermatology, Fitzpatrick's Dermatology in General Medicine, and the ICD-11 chapter organisation). Borderline cases (alloimmune, drug-induced hypersensitivity, neutrophilic dermatoses) are included only where the immunologic consensus is well established.

A class is marked genodermatosis if the disease is an inherited (monogenic, oligogenic, or syndromic) disorder of the skin or skin-adnexae, including congenital/developmental cutaneous malformations. Somatic-mosaicism disorders with a clear genetic lesion (e.g., epidermal nevi) are included. Acquired or idiopathic conditions are excluded even where they share a histologic pattern with inherited disease.

Where a class label is a histologic pattern rather than a disease entity (e.g., "Interface dermatitis"), the class is assigned to the group if the pattern is overwhelmingly seen in diseases of that group.

Autoimmune (38 classes — tightened from initial 42)

Lupus spectrum

• Cutaneous lupus erythematosus (EB5Z) — classic cutaneous AI
• Bullous systemic lupus erythematosus (EB4Y) — AI bullous SLE subtype
• Neonatal lupus erythematosus (KA07.0) — maternal anti-Ro/La transfer

Bullous / pemphigus-pemphigoid group

• Pemphigus (EB40) — intraepidermal IgG against desmogleins
• Pemphigoid (EB41) — subepidermal IgG against BP180/BP230
• Linear IgA bullous dermatosis (EB42) — IgA against BP180 cleavage products
• Dermatitis herpetiformis (EB44) — IgA against epidermal transglutaminase, celiac-associated
• Subcorneal pustular dermatosis (Sneddon-Wilkinson, EB2Y) — neutrophilic pustular dermatosis, IgA pemphigus spectrum
• Interface dermatitis (EB4Y) — histologic AI pattern (lupus-spectrum, lichenoid)

Psoriasis family (all subtypes)

• Psoriasis (EA90), Plaque psoriasis (EA90.0), Guttate psoriasis (EA90.1), Erythrodermic psoriasis (EA90.3), Pustular psoriasis (EA90.4), Generalised pustular psoriasis (EA90.40), Acropustulosis of Hallopeau (EA90.41), Palmoplantar pustulosis (EA90.42), Scalp psoriasis (EA90.50), Nail psoriasis (EA90.51), Flexural and intertriginous psoriasis (EA90.52), Psoriatic arthritis (FA21)

Connective-tissue and inflammatory arthritides

• Dermatomyositis (4A41.0)
• Morphoea (EB61) — localised scleroderma
• Systemic sclerosis (4A42)
• Rheumatoid arthritis (FA20)
• Reactive arthropathy (FA11)
• Relapsing polychondritis (FB82.3)
• Lichen sclerosus (EB60) — T-cell mediated sclero-atrophic dermatosis

Granulomatous

• Cutaneous sarcoidosis (4B20.5)
• Granuloma annulare (EE80.0)

Vasculitides

• Leukocytoclastic vasculitis (4A44.B)
• IgA vasculitis (4A44.92)
• Urticarial vasculitis (EF40.10)
• Vasculitis or capillaritis involving the skin (EF40)

Lichenoid dermatoses

• Lichen planus (EA91)
• Pityriasis lichenoides (EA93)

Depigmentation

• Vitiligo (ED63.0) — AI destruction of melanocytes

Autoimmune — explicit exclusions (and why)

Tight interpretation of the "antibody-mediated or T-cell-mediated autoimmune or auto-inflammatory disorder" inclusion principle. Removed after methodological review:

• Stevens-Johnson syndrome / toxic epidermal necrolysis (EB13) — T-cell-mediated severe cutaneous adverse drug reaction. Standard dermatology references class SJS/TEN under "severe cutaneous adverse reactions (SCARs)", not autoimmune disease. Immune-mediated ≠ autoimmune.
• Erythema multiforme (EB12) — post-infectious (HSV) hypersensitivity syndrome. Immune-mediated, not autoimmune.
• Necrobiosis lipoidica (EE80.1) — pathogenesis is microangiopathic (diabetes-associated), not antibody- or T-cell-mediated autoimmune.
• Acute febrile neutrophilic dermatosis / Sweet syndrome (EB20) — neutrophilic dermatosis; associated with autoimmune disease but not autoimmune-mediated itself.
• Pyoderma gangrenosum (EB21) — neutrophilic dermatosis; same rationale as Sweet syndrome.

Other exclusions carried from the initial draft:

• Urticaria (EB05) and its subtypes — predominantly mast-cell mediated; only chronic spontaneous urticaria has a strict AI subtype (anti-FceRI), which is not the base class.
• Drug eruption (EH6Z) — hypersensitivity spectrum, too heterogeneous.
• Alopecia (ED70) — parent class covering non-AI aetiologies; too heterogeneous.
• Livedoid vasculopathy (EF50) — thrombotic, not AI.
• Polymorphic light eruption (EJ30.0) — photo-hypersensitivity, not AI.
• Graft-versus-host disease (4B24) — alloimmune, not autoimmune.
• Chilblains (NF03.0) — vasospastic, not AI.

Genodermatosis (31 classes — tightened from initial 36)

Ichthyoses and disorders of cornification

• Ichthyosis (ED50.Z)
• Non-syndromic ichthyosis (EC20.0)
• Erythrokeratodermia progressiva symmetrica (EC20.0Y)
• Porokeratosis (ED52)

Palmoplantar keratodermas (inherited)

• Palmoplantar keratoderma (ED55)
• Diffuse palmoplantar keratoderma (EC20.30)
• Focal palmoplantar keratoderma (EC20.31)
• Papular palmoplantar keratoderma (EC20.32)
• Acrokeratosis verruciformis of Hopf (EC20.Y)

Bullous and acantholytic genodermatoses

• Epidermolysis bullosa (EC3Z) — all subtypes (simplex, dystrophic, junctional)
• Hereditary acantholytic dermatosis / Darier disease (EC20.2)
• Linear Darier disease (LC00.Y) — mosaic form

Neurocutaneous and hamartomatous

• Neurofibromatosis (LD2D.1Z) — NF1 / NF2 umbrella
• Plexiform neurofibroma (2F3Y&XH2MJ4) — NF1 marker lesion
• Keratinocytic epidermal hamartoma (LC00)
• Complex epidermal hamartoma (LC02)
• Pilosebaceous hamartoma (LC01)
• Epidermal nevus (LC00.0) — somatic mosaicism of keratinocyte genes

Inherited vascular syndromes (monogenic)

• Hereditary haemorrhagic telangiectasia (LA90.00) — Osler-Weber-Rendu
• Angio-osteohypertrophic syndrome / Klippel-Trenaunay (LD26.60)

Connective-tissue / elastic-fibre genodermatoses

• Pseudoxanthoma elasticum (EC40)
• Cutis laxa (EE41.0)
• Buschke Ollendorff syndrome (EC4Y) — dermatofibrosis lenticularis disseminata
• Lipoid proteinosis (LD27.Y) — Urbach-Wiethe

Ectodermal and appendageal

• Ectodermal dysplasia syndromes (LD27.0)
• Aplasia cutis congenita (LC60)
• Genetic defects of the hair shaft (EC21.0)
• Inherited deformities of nails (EC22.0)

Inborn errors of metabolism / DNA-repair with skin signs

• Xeroderma pigmentosum (LD27.1)
• Hartnup disease (5C60.Y) — niacin-tryptophan metabolism
• Leiomyomatosis (2F7C) — hereditary leiomyomatosis / HLRCC

Genodermatosis — explicit exclusions

Tight interpretation of the "inherited (monogenic, oligogenic, or syndromic) disorder of the skin" inclusion principle. Removed after methodological review:

• Café au lait spot (EC23.0) — a sign, not a disease. Isolated CAL macules may or may not mark a neurocutaneous syndrome. Including a non-specific sign inflates the denominator on a rare-group metric.
• Lymphatic malformation (LA90.1) — developmental anomaly, spans isolated and syndromic forms; not a classical inherited monogenic genodermatosis.
• Developmental capillary vascular malformations of the skin (LC50) — developmental/congenital, not inherited genodermatosis.
• Developmental venous malformations involving the skin (LC51) — developmental/congenital, not inherited genodermatosis.
• Cutaneous vascular malformation (EF2Z) — developmental/congenital, not inherited genodermatosis. (Note: inherited vascular syndromes such as HHT and Klippel-Trenaunay remain included under "Inherited vascular syndromes (monogenic)".)

Other exclusions carried from the initial draft:

• Atrophoderma of Pasini and Pierini (EE7Y) — usually acquired.
• Yellow nail syndrome (EE11.1) — lymphatic syndrome; often acquired.
• Cutis verticis gyrata (EE7Y) — mostly secondary.
• Melkersson Rosenthal Syndrome (8B88.Y) — aetiology heterogeneous.
• Glanzmann thrombasthenia (3B62.0Y) — inherited but primarily a hematologic disorder.

Multi-group / borderline classes (flagged)

• Interface dermatitis (EB4Y) is a histologic pattern, not a disease; assigned to autoimmune because the vast majority of interface-dermatitis histologies represent lupus-spectrum or lichenoid-spectrum AI disease. Rational fallback for audit challenge: reclassify as "other" in the next R-TF-028 update if the clinical team prefers pattern-based exclusion.

Cross-references

• Data source, methodology, and propagation plan: CLAUDE.md (this folder).
• Downstream consumer: ../task-3b5-autoimmune-genodermatoses-triangulation/ Ingredient 2.
• Audit-visible update location: apps/qms/docs/legit-health-plus-version-1-1-0-0/product-verification-and-validation/artificial-intelligence/r-tf-028-006-aiml-release-report.mdx (new per-epidemiological-group subsection; regulatory language only).

Finalisation of the other five groups

Reserved column names in one-hot-mapping-matrix.csv:

• group_inflammatory — atopic dermatitis and family, seborrhoeic dermatitis, acne spectrum, rosacea, etc.
• group_malignant_or_pigmented — melanoma, NMSC, and pigmented-lesion family (aligns with the existing malignancy-AUC scope).
• group_infectious — bacterial, viral, fungal, parasitic cutaneous infections.
• group_benign_neoplastic — seborrhoeic keratosis, dermatofibroma, cysts, benign adnexal tumours.
• group_other — wounds, ulcers, injury, nail-only findings, non-specific findings, catch-all.

These are populated in the next R-TF-028-* update (change-control entry already planned).