Urticaria/angioedema-type sensitivity to aspirin and other nonsteroidal anti-inflammatory drugs. Diagnostic value of anamnesis and challenge test with acetylsalicylic acid.

The aim of this study was to determine the value of challenge tests with acetylsalicylic acid in the diagnosis of ASA-induced urticaria. The study was performed in 71 patients with suspected urticaria/angioedema-type sensitivity to ASA. Anamnesis confirmed sensitivity in 67 patients (94.4%) and showed that sensitive patients usually suffered from extensive urticaria (37 patients, i.e 55.5%) after ingestion of ASA. Eight patients (12%) reacted with loss of consciousness and 4 (6.0%) with edema of the larynx. Oral challenge test with acetylsalicylic acid was performed in 53 patients, in 49 (92.4%) of whom it was positive. Threshold doses of acetylsalicylic acid ranged from 40 to 300 mg. In 11 patients, the test was repeated and in 8 it was performed 3 times. It was observed that both the threshold acetylsalicylic acid doses and the time of appearance of sensitivity symptoms were variable. All ASA-sensitive patients reacted to indomethacin in a similar manner as to ASA. Paracetamol, on the other hand, was well tolerated by all 25 evaluated patients with urticaria/angioedema-type sensitivity to ASA.