On direct immunofluorescence (DIF) of perilesional skin, intercellular IgG deposition in a 'fishnet/chicken-wire' pattern throughout the epidermis is MOST characteristic of:
- A Bullous pemphigoid
- B Dermatitis herpetiformis
- C Pemphigus vulgaris ✓
- D Linear IgA disease
Correct answer: C. Pemphigus vulgaris
Explanation
The 'fishnet' or 'chicken-wire' intercellular IgG (and C3) pattern on DIF is pathognomonic of pemphigus vulgaris. It reflects IgG autoantibodies against desmoglein-3 (and desmoglein-1 in mucocutaneous type) coating keratinocyte surfaces. Bullous pemphigoid shows linear IgG/C3 at the DEJ; dermatitis herpetiformis shows granular IgA deposits in dermal papillae; linear IgA disease shows homogeneous linear IgA at the DEJ.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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