Linear IgA bullous dermatosis associated with ulcerative proctitis: treatment challenge.

Linear IgA bullous dermatosis is a rare bullous disease in children and adults that can be associated with autoimmune conditions, malignancies, infections, or medication exposure. The definitive diagnosis relies on the biopsy. A 58-year-old man presented to our clinic with a pruritic vesicular and bullous eruption. Histology showed the classic findings of a subepidermal blister with neutrophilic infiltrate and linear IgA deposition along the dermal-epidermal junction. Upon further evaluation, he was diagnosed with ulcerative proctitis. His therapy was complicated owing to side effects and lack of response to the standard treatment options. Dapsone, a first-line therapy, caused symptomatic methemoglobinemia whereas niacinamide with doxycycline were not effective. He required intravenous and oral steroids to reach improvement followed by transitioning to methotrexate.