Drug-Induced Linear IgA Bullous Dermatosis Emerging After Vancomycin Discontinuation in Renal Impairment: Management Amid Serious Infection

Linear immunoglobulin A (IgA) bullous dermatosis (LABD) is a rare autoimmune blistering disease presenting with subepidermal blisters and linear IgA antibody deposition in the dermal-epidermal junction. We report a case of a 48-year-old man who was switched to vancomycin for the treatment of <i>Clostridium</i> bacteremia following a morbilliform eruption from piperacillin-tazobactam. Two days after stopping vancomycin, he developed tense vesicles and bullae on an erythematous base located on the upper torso and upper extremities. One day prior to the development of his eruption, he also developed an acute kidney injury (AKI). A skin biopsy demonstrated subepidermal blistering, and direct immunofluorescence of the perilesional skin revealed linear IgA positivity at the dermal-epidermal junction, confirming the diagnosis of LABD. Serum vancomycin levels were drawn, revealing peaked levels one day after cessation, likely secondary to a developing AKI impairing excretion and contributing to the delayed development of the eruption. He was treated with wet occlusive dressings along with a prednisone taper, and the eruption began to resolve. Typically, worsening drug eruptions prompt a review of medications currently being taken; however, this case highlights the importance of considering pharmacokinetic factors that may lead to adverse reactions even if the offending drug has been discontinued.