Fever and rigors as sole symptoms of azathioprine hypersensitivity

The case history of a haemodialysis patient with fever and rigors is presented. This diagnostic problem turned out to be a hypersensitivity reaction to azathioprine, with identical complaints recurring after a rechallenge with azathioprine, findings which resolved on discontinuation of this drug. The more extended indications for use of azathioprine warrant attention to the possibility of side-effects like drug fever.