Allopurinol-induced hypersensitivity reaction in a patient of underlying renal impairment

A 74-year-old elderly female admitted to a tertiary care hospital with a history of nonsteroidal anti-inflammatory drug abuse taking allopurinol for hyperuricemia presented with, rashes and renal impairment. Allopurinol which was originally discovered for neoplastic conditions such as leukemia, and eventually marketed for gout, is a medication used to treat hyperuricemia, prevention of gout, certain kinds of kidney stones, and elevated uric acid levels that may arise after chemotherapy. It is taken orally or intravenously. Allopurinol may lead to hypersensitivity reactions consisting of rashes, fever, malaise, and muscle pain, and its incidence increases in patients with renal impairment. Rarely, allopurinol may also lead to serious side effects such as drug reaction with eosinophilia and systemic symptoms, Stevens–Johnson syndrome, and toxic epidermal necrolysis. Drug-drug interactions, as well as drug-disease interactions, are also associated with allopurinol. The following case report illustrates the fact that allopurinol increases the chance of rashes in a patient with underlying renal impairment.