Oral aspirin challenges in patients with a history of intolerance to single non-steroidal anti-inflammatory drugs.

UNLABELLED: Summary Background In the clinical practice patients with a history of acute urticaria induced by a single non-steroidal anti-inflammatory drug (NSAID) and seeking for safe alternative drugs generally undergo tolerance tests with alternative NSAIDs that have little or no cyclooxygenase-1 (COX-1) enzyme inhibitory activity. This practice does not allow for the detection of single NSAID reactors and may lead to unnecessary avoidance of many potentially useful NSAIDs.

OBJECTIVE: Evaluate aspirin challenge as a means to distinguish single from multiple NSAID intolerance in patients with a clinical history of acute urticaria induced by a single NSAID. Methods One hundred and seventeen otherwise normal subjects with a history of acute urticaria following the ingestion of a single NSAID (pyrazolones (n=58), nimesulide (n=17), propionic acid derivatives (n=13), aryl acetic acid derivatives (n=14), acetaminophen (n=9), piroxicam (n=5), and indometacin (n=1)) underwent single-blind placebo-controlled oral challenges with aspirin. Aspirin-intolerant subjects underwent further tolerance tests drugs exerting little or no inhibitory activity on COX-1 enzyme (including paracetamol, nimesulide, rofecoxib, tramadol, and floctafenine). Results Aspirin induced urticaria in 28/117 (24%) patients. Five out of 28 (18%) aspirin reactors did not tolerate alternative NSAID on subsequent oral challenges. Conclusion In subjects with a history of urticaria induced by a single NSAID (other than aspirin) the diagnostic workup should start with an aspirin challenge in order to detect single/multiple NSAID reactors.