Azathioprine hypersensitivity reaction in a patient with ulcerative colitis.

Objective: To describe a case of azathioprine hypersensitivity in a patient with ulcerative colitis.

Case Summary: A 40-year-old white man with ulcerative colitis, treated with chronic mesalamine and occasional steroids, was admitted to the hospital with a 3-day history of fever, nausea, vomiting, and a rash. Fourteen days prior to admission, the patient had been started on azathioprine for ulcerative colitis.