A report of a rare immediate reaction after ingestion of acetaminophen

Background: Acetaminophen hypersensitivity is rare and, when seen, is usual ly in association with sensitivity to nonsteroidal anti-inflammatory drugs. Methods: This is a case report of an immediate reaction to acetaminophen, c onfirmed by a drug challenge, in a subject who tolerated ibuprofen. Results: After an oral challenge with 50 mg of acetaminophen, the subject h ad generalized pruritus, urticaria, and dyspnea. Conclusions: This patient demonstrates a rare but potentially severe reacti on to acetaminophen that may occur in patients who are not otherwise sensit ive to other nonsteroidal anti-inflammatory drugs.