Linear IgA Bullous Dermatosis (LABD)

Figure 3.27 A: Cicatricial pemphigoid (Courtesy of Dr. Iris K. Aronson) B: Cicatricial pemphigoid (Courtesy of Dr. Iris K. Aronson) C: LABD, DIF (Courtesy of Dr. Lawrence Chan)

• Rare, subepidermal blistering disease with IgA deposition at BMZ; likely identical to chronic bullous disease of childhood (CBDC)
• Autoantigen: LAD-1 (120 kDa, part of BPAG2); LAD-1 cleavage results in second autoantigen, LABD97 (97 kDa)
• Clinical: annular or grouped vesicles/bullae over extensor extremities and buttock typically in herpetic arrangement; mucosal involvement
• Drug-induced: vancomycin (most common), captopril, cephalosporin, PCN, NSAIDs, phenytoin, sulfonamide
• Histology: subepidermal bullae with rich neutrophilic infiltrate in papillary dermis (may resemble DH)
• DIF: linear IgA (± C3) deposition at BMZ
• IIF: + in 60% cases, IIF on (SSS) shows binding to epidermal side of split (roof)
• Treatment: dapsone or sulfapyridine, low dose oral corticosteroid