Bullous Erythema Multiforme Secondary to Trimethoprim-Sulfamethoxazole Use, Treated With Cyclosporine in a 91-Year-Old Male.

Erythema multiforme is an acute, immune-mediated, mucocutaneous condition in which 90% of cases are triggered by infection. The second most common cause is drug-induced. It classically presents with itchy, burning targetoid lesions on the skin and mucous membranes. The lesions may be mistaken for other conditions, and thus, rapid and correct diagnosis is crucial. It is most often treated with corticosteroids, though non-responders or those with weakened immune systems may require immunomodulatory therapy. We present the case of a 91-year-old male who developed bullous erythema multiforme after treatment with trimethoprim-sulfamethoxazole who was successfully treated with cyclosporine.