Azathioprine hypersensitivity presenting as cardiogenic shock and Sweet's syndrome in a patient with microscopic polyangiitis.

Azathioprine hypersensitivity is a clinical syndrome which may manifest from isolated fever and rash to multi-organ failure. This rare condition is usually self-limiting following the discontinuation of azathioprine. Therefore, it is important to maintain a high index of clinical suspicion for hypersensitivity reactions with azathioprine therapy. We report a case of azathioprine hypersensitivity in a 69-year-old woman who developed cardiogenic shock and Sweet's syndrome following the initiation of azathioprine for her underlying autoantibodies to neutrophil cytoplasmic antigens (ANCA) associated microscopic polyangiitis.