Severe Allopurinol Hypersensitivity

Allopurinol, introduced in 1963,¹has proved to be a useful agent for the treatment of gout and hyperuricemia.²⁻⁷Although serious toxicity has been unusual, recent case reports of agranulocytosis,⁸granulomatous hepatitis,⁹and exfoliative dermatitis¹⁰have appeared. In addition, four cases have been reported of severe, prolonged hypersensitivity reactions characterized by an erythematous maculopapular eruption, eosinophilia, fever, abnormal results of liver-function tests, and rapidly progressive renal failure.¹¹⁻¹³The purpose of this communication is to describe two further cases of apparent hypersensitivity vasculitis and to explore possible predisposing factors. Patient Summaries Patient 1. —A 40-year-old black man was admitted to Vanderbilt University Hospital on April 14,1971, with a chief complaint of skin rash and fever. The patient's course had been followed at Vanderbilt since 1953 for psychomotor seizures, controlled with diphenylhydantoin sodium and phenobarbital. In 1963, during an evaluation for hypertension (blood pressure, 180/110 mm Hg),