Annular bullous diseases

Linear Immunoglobulin A (IgA) Bullous Dermatosis Mimicking Stevens-Johnson Syndrome

Linear IgA bullous dermatosis (LABD) is a rare autoimmune blistering disease characterized by linear IgA deposition along the dermo-epidermal junction on direct immunofluorescence (DIF). LABD appears clinically as erythematous polycyclic lesions in younger patients but can show considerable phenotypic heterogeneity in older patients, often leading to misdiagnoses such as bullous pemphigoid, pemphigus vulgaris, Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), or other bullous conditions. Cases of LABD mimicking SJS/TEN require prompt skin biopsies for histopathology and DIF for disease differentiation and medical decision-making. In cases of suspected drug-induced LABD or SJS/TEN, identification and removal of the offending agent are paramount. The preferred treatment for LABD is oral dapsone, while SJS/TEN may respond better to cyclosporine or a combination of intravenous immunoglobulin and systemic corticosteroids. This case highlights the rare occurrence of LABD mimicking SJS/TEN and emphasizes the details that clinicians must know to guide patient management.