Pemphigus vulgaris: The Daily PANCE Blueprint
A 42-year-old woman presents with a 3-month history of progressively painful skin lesions and difficulty eating. She reports that the lesions began as blisters that rupture easily, leaving raw, eroded areas. Physical examination reveals multiple flaccid bullae and erosions on the trunk and scalp, along with shallow ulcerations of the oral mucosa. Gentle lateral pressure on uninvolved skin results in epidermal sloughing (positive Nikolsky sign). A skin biopsy is performed. Which of the following findings would best confirm the diagnosis?
A. Intercellular IgG deposition in a “fishnet” pattern
B. Linear IgG and C3 deposition along the basement membrane
C. Granular IgA deposition within the dermal papillae
D. Subepidermal blister formation with prominent eosinophils
E. Linear IgA deposition along the basement membrane zone
The answer is A. Intercellular IgG deposition in a “fishnet” pattern
This patient’s presentation is classic for pemphigus vulgaris, an autoimmune blistering disorder caused by IgG autoantibodies against desmoglein 3 (± desmoglein 1), which are critical components of desmosomes responsible for keratinocyte adhesion.
Key features pointing to pemphigus vulgaris:
- Painful, flaccid bullae that rupture easily
- Mucosal involvement (oral erosions are common and often precede skin findings)
- Positive Nikolsky sign, reflecting intraepidermal acantholysis
Direct immunofluorescence demonstrates intercellular IgG deposition in a reticular (“fishnet”) pattern throughout the epidermis, which is diagnostic.
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Covered under ⇒ PANCE Blueprint Dermatology ⇒ Vesiculobullous disease ⇒ Pemphigus Vulgaris