A Rapidly Evolving Vesiculobullous Eruption in a Toddler: A Case of Linear IgA Bullous Dermatosis

Linear immunoglobulin A (IgA) bullous dermatosis (LABD) is a rare autoimmune neutrophilic dermatosis that can mimic viral or molluscoid eruptions, thereby delaying treatment. We report a 2‐year‐old girl with a 2‐week history of pruritic vesiculobullous rash that began as a single “mosquito bite.” Multiple emergency department visits led to empiric acyclovir and topical steroids. Histopathologic confirmation of LABD, essential for diagnosis, was achieved by a skin biopsy performed on Day 8, which revealed a subepidermal bulla with 3+ linear IgA deposition at the dermoepidermal junction. She improved after dapsone dosed daily at 1 mg/kg −1 , plus a tapering course of prednisolone. Therefore, early consideration of LABD in toddlers with disseminated evolving vesicular lesions can prevent unnecessary treatments and expedite more targeted immunosuppressive therapy.