Nonsteroidal anti-inflammatory drug hypersensitivity: fable or reality?

In the medical community lectures and publications about nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity have led to an increasing awareness and diagnosis of this condition. Frequently, the diagnosis NSAID hypersensitivity is based only on history, which is a vague and unreliable indicator. A two-stage diagnostic procedure with skin tests (to exclude IgE-mediated allergy) followed by single-blinded, placebo-controlled oral challenges was carried out on patients attending our clinic from 1997 to 2003 with the diagnosis of a NSAID hypersensitivity. Out of 260 patients tested, 61.5% described their NSAID hypersensitivity as cutaneous (urticaria, angioedema), 24.2% had respiratory symptoms (asthma, rhinitis), 3.5% had anaphylactoid reactions, and 10.8% described uncertain signs. In fact 55.0% of all patients previously labelled as NSAID sensitive tolerated NSAID when assessed by oral challenge, whereas 13.8% were truly NSAID sensitive. In 31.2% of patients the challenge test with the suspicious drug was either not done or rejected by the patient; but all showed a proven tolerance of alternative NSAID. Our study demonstrates that oral challenge tests are safe, practical and useful in ruling out NSAID hypersensitivity in approximately 50% of the patients who have previously been labelled as such.