Direct immunofluorescence from lesional skin of dermatitis herpetiformis (DH) characteristically shows:
- A Linear IgA deposits at the dermoepidermal junction
- B Intercellular IgG deposits in the epidermis
- C Granular IgA deposits in the dermal papillae ✓
- D Fibrinogen deposits along the basement membrane
Correct answer: C. Granular IgA deposits in the dermal papillae
Explanation
Dermatitis herpetiformis is pathognomonic for granular IgA deposits in the tips of the dermal papillae on DIF of perilesional skin (lesional skin may be negative due to neutrophil-mediated IgA consumption). The granular pattern reflects IgA targeting epidermal transglutaminase (eTG/TG3) deposited as immune complexes. Linear IgA at the BMZ is characteristic of Linear IgA bullous dermatosis (LABD), not DH. IgG intercellular deposits define pemphigus.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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