# Pemphigus Vegetans, Erythematosus and IgA Pemphigus

> Pemphigus vegetans, pemphigus erythematosus and IgA pemphigus for NEET-PG Dermatology, with vegetating plaques, desmoglein antigens, eosinophils and dapsone.

- Canonical URL: https://prepelephant.com/topics/neet-pg/dermatology/pemphigus-vegetans-and-variants
- Exam / course: NEET-PG · Subject: Dermatology
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Rook's Textbook of Dermatology; IADVL Textbook of Dermatology
- How to cite: "Pemphigus Vegetans, Erythematosus and IgA Pemphigus", PrepElephant, https://prepelephant.com/topics/neet-pg/dermatology/pemphigus-vegetans-and-variants

## Direct answer

Pemphigus vegetans, pemphigus erythematosus and IgA pemphigus are rarer variants of the pemphigus group, each with its own antigen, site and inflammatory cell. Pemphigus vegetans produces vegetating, warty plaques in skin folds, while pemphigus erythematosus is a superficial, seborrhoeic disease that usually spares the mouth. IgA pemphigus shows intercellular IgA rather than IgG on direct immunofluorescence, and dapsone is often effective in it.

## What you must remember

- **Vegetans pattern:** vegetating, warty plaques in flexures, which may follow pemphigus vulgaris (Neumann type) or arise without it (Hallopeau type).
- **Vegetans antigen:** desmoglein 3, the same target as pemphigus vulgaris, so the two differ mainly in morphology and cell content.
- **Vegetans histology:** eosinophils within acantholytic cavities, with pseudoepitheliomatous hyperplasia of the epidermis.
- **Erythematosus pattern:** crusted, erythematous seborrhoeic plaques on the face, scalp and upper trunk, with the mucosa typically spared.
- **Erythematosus antigen:** desmoglein 1, the same target as pemphigus foliaceus, which explains the superficial distribution.
- **IgA pemphigus:** intercellular IgA on direct IF, with neutrophilic pustules that lie intraepidermally or beneath the stratum corneum.
- **IgA therapy:** dapsone is often the first choice, and textbooks differ on the exact antigens, so the immunoglobulin class matters most.

## Mapping the variants by antigen and site

Pemphigus vegetans, pemphigus erythematosus and IgA pemphigus share the acantholytic split of pemphigus but differ in antigen, site and inflammatory cell. Each row below is a separate exam answer, so the table is worth memorising line by line.

| Variant | Main antigen | Clinical hallmark | Histology and IF |
| --- | --- | --- | --- |
| Pemphigus vegetans | Desmoglein 3 | Vegetating plaques in folds | Eosinophils in acantholytic cavities, intercellular IgG |
| Pemphigus erythematosus | Desmoglein 1 | Crusted seborrhoeic plaques, mucosa spared | Superficial acantholysis, intercellular IgG |
| IgA pemphigus, intraepidermal type | Desmoglein 1 (books differ) | Pustules and erosions, often on the trunk | Neutrophils, intercellular IgA |
| IgA pemphigus, subcorneal type | Desmocollin 1 | Superficial pustules, often on the trunk | Subcorneal neutrophilic pustules, intercellular IgA |

The desmoglein 3 versus desmoglein 1 split and the eosinophil versus neutrophil content are the points examiners test most often. Confirming the immunoglobulin class is the step that changes treatment in IgA disease.

Vegetans is the variant most often mistaken for an infection in the flexures, while IgA disease is missed when the reader expects a fishnet IgG pattern.

## Where candidates lose marks

Variant questions usually turn on the site of the lesions and the immunoglobulin class.

- **Trap:** treating intertriginous vegetating plaques as candidiasis or bacterial infection — **Correct:** a biopsy showing acantholysis with eosinophils and intercellular IgG confirms pemphigus vegetans.
- **Trap:** assuming pemphigus erythematosus involves the mouth — **Correct:** it is a superficial, seborrhoeic disease that usually spares the mucosa, unlike pemphigus vulgaris.
- **Trap:** using the IgG pattern to label every pustular pemphigus — **Correct:** intercellular IgA on direct IF defines IgA pemphigus, and dapsone is often the first choice.

## Frequently asked questions

### Which antigen is targeted in pemphigus erythematosus?

Pemphigus erythematosus is caused by IgG autoantibodies against desmoglein 1, which explains its superficial, seborrhoeic distribution. Mucosal involvement is typically absent because oral mucosa depends mainly on desmoglein 3.

### Which histological clue points to pemphigus vegetans?

Eosinophils within acantholytic cavities and pseudoepitheliomatous hyperplasia are the classic histological clues to pemphigus vegetans. Direct immunofluorescence then shows intercellular IgG, confirming a pemphigus variant.

### Why is dapsone useful in IgA pemphigus?

Dapsone is often effective in IgA pemphigus and is commonly tried early, especially in the neutrophilic forms. Its exact mechanism in this disease is not fully understood, so response and haematological effects still need monitoring.

### How is IgA pemphigus distinguished from pemphigus vulgaris?

IgA pemphigus shows intercellular IgA rather than IgG on direct immunofluorescence, and its pustules are neutrophilic rather than dominated by acantholysis. Oral involvement is also less common in IgA pemphigus than in pemphigus vulgaris.

### What separates the Neumann and Hallopeau types of pemphigus vegetans?

The Neumann type usually follows pemphigus vulgaris, whereas the Hallopeau type often arises in flexures without a preceding vulgaris phase. Clinical course and the history of pemphigus vulgaris guide the label as much as histology does.