On DIF of a patient with linear IgA bullous dermatosis, which pattern and immunoreactant is expected?

• A Intercellular IgG throughout epidermis
• B Linear IgA at the dermoepidermal junction ✓
• C Granular IgA in papillary dermis
• D Linear C3 at the DEJ without immunoglobulins

Explanation

Linear IgA bullous dermatosis (LABD) is defined by linear deposits of IgA (alone or predominant) at the dermoepidermal junction on DIF of perilesional skin. The target antigen is LAD-1 (a 120 kDa ectodomain of BP180/BPAG2). It can be idiopathic or drug-induced (vancomycin is the classic culprit). Granular IgA in papillae indicates DH; linear IgG/C3 indicates bullous pemphigoid.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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