Pemphigus
- Lesion
In pemphigus, antibodies cut the glue between skin cells. Fragile blisters break easily and leave raw areas, often in the mouth.
What it is
Pemphigus is a group of autoimmune blistering diseases in which IgG autoantibodies bind desmogleins, the cadherins of desmosomes, causing acantholysis. Pemphigus vulgaris targets desmoglein 3 (with or without 1) and splits just above the basal layer, involving mucosa; pemphigus foliaceus targets desmoglein 1 and splits high, sparing mucosa. Paraneoplastic pemphigus accompanies lymphoid neoplasms. The level of the split explains how each blister looks.
Structure
- Vulgaris: suprabasal acantholytic blister with rounded, detached keratinocytes in the cavity; basal cells remain attached to the basement membrane.
- Foliaceus: acantholysis at the granular layer, often with neutrophils; blister roof very thin.
- Perilesional skin is needed for direct immunofluorescence.
Where the blister forms
| Level | Disease | Target | Immunofluorescence |
|---|---|---|---|
| Subcorneal or granular | Pemphigus foliaceus; staphylococcal scalded skin | Desmoglein 1 (antibody or toxin) | Intercellular IgG upper epidermis (foliaceus); none (toxin) |
| Suprabasal | Pemphigus vulgaris | Desmoglein 3 (± 1) | Intercellular IgG, fishnet |
| Subepidermal, lamina lucida | Bullous pemphigoid | BP180, BP230 | Linear IgG and C3 at the basement membrane |
| Subepidermal, dermal papillae | Dermatitis herpetiformis | Epidermal transglutaminase | Granular IgA in papillary tips |
| Below the lamina densa | Epidermolysis bullosa acquisita; dystrophic EB | Type VII collagen | Linear IgG (acquired); none (inherited) |
Clinical notes
- Before steroids, pemphigus vulgaris was often fatal through infection and fluid loss.
- Drug-induced pemphigus: penicillamine, captopril.
- Anti-CD20 therapy is now a first-line treatment.
Test yourself
Think of the answer, then tap the question to see it.
Which antigen is targeted in pemphigus vulgaris?
Desmoglein 3 (often with desmoglein 1), a desmosomal cadherin.
What is the direct immunofluorescence pattern in pemphigus?
Intercellular, net-like (fishnet) IgG and C3 deposition between keratinocytes.
Why does pemphigus foliaceus spare the mouth?
It targets desmoglein 1, while oral mucosa relies mainly on desmoglein 3, which compensates.
Elsewhere in DurgiPedia
- Type II hypersensitivity (antibody against cells)
- Immunofluorescence and the ANA test
- Where blisters form: pemphigus vs pemphigoid
- Cell junctions: tight, adherens, desmosomes, gap, hemidesmosomes
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Blisters (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.