Allopurinol hypersensitivity syndrome.

Allopurinol hypersensitivity syndrome (AHS) is an infrequent but life-threatening adverse reaction of allopurinol therapy. The records of 38 patients with the allopurinol hypersensitivity syndrome evaluated at the Veterans General Hospital-Taipei were reviewed. The clinical pictures included fever, rash, leukocytosis, eosinophilia, impaired renal function and hepatocellular injury. Nine patients died (24%) and the major cause of death was infection. The use of corticosteroids increased neither survival nor mortality rate. Twenty-six percent of patients were treated with allopurinol for asymptomatic hyperuricemia, which was not an established indication of the drug, should be avoided. The most important factor of mortality was toxic epidermal necrolysis (TEN) (p < 0.001 compared with other skin lesions). As there is no way to identify the risk group of patients or to make effective treatment for AHS, the only means of minimizing the incidence of AHS is to limit the allopurinol therapy to accepted indications and to adjust the dosage for the patient's renal function.