A 55-year-old woman presents with recurrent annular clusters of pustules over the trunk and flexures without mucosal involvement. Histology shows a subcorneal pustule filled with neutrophils. DIF reveals intercellular IgA throughout the epidermis. She improves markedly on dapsone. What is the diagnosis?

• A Subcorneal pustular dermatosis type of IgA pemphigus ✓
• B Intraepidermal neutrophilic type of IgA pemphigus
• C Pemphigus foliaceus
• D Linear IgA bullous dermatosis

Explanation

IgA pemphigus has two main patterns. The subcorneal pustular dermatosis type shows a subcorneal neutrophilic pustule with intercellular IgA targeting desmocollins, and responds well to dapsone. The intraepidermal neutrophilic type shows pustules at various epidermal levels. Linear IgA bullous dermatosis produces a subepidermal blister with linear basement membrane zone IgA, not an intercellular pattern, which excludes option D.

Reference: Bolognia, Schaffer and Cerroni, Dermatology, 5th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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