Linear immunoglobulin A bullous dermatosis in childhood with an atypical granular pattern: importance of early differential diagnosis

Linear immunoglobulin A bullous dermatosis (LABD) is a rare autoimmune blistering disease, more frequent in childhood, characterized by vesiculobullous lesions and linear immunoglobulin A (IgA) deposition along the basement membrane zone. We report the case of a 4-year-old child with typical LABD lesions but showing a granular IgA pattern on direct immunofluorescence, raising a diagnostic consideration of dermatitis herpetiformis. However, negative serologic tests and the absence of gastrointestinal symptoms, along with a favorable response to dapsone despite no gluten-free diet, supported the diagnosis of LABD. Bullous impetigo, bullous pemphigoid, and epidermolysis bullosa acquisita were excluded based on clinical and immunopathological features. This case underscores the importance of early clinical recognition and accurate differential diagnosis, even in the presence of atypical findings. Prompt initiation of dapsone led to complete remission, emphasizing the critical role of dermatologists in ensuring optimal outcomes in this uncommon condition.