Aspirin "desensitization" in patients with aspirin-induced urticaria and angioedema.

The study was performed on 22 patients with sensitivity to aspirin which manifested as urticaria and angioedema. Sensitivity to aspirin was established based on the anamnesis of urticaria and angioedema occurring after ingestion of aspirin and oral challenge tests with acetylsalicylic acid. At first, the threshold dose of aspirin in all patients and additionally of indomethacin in 12 patients was established. Aspirin "desensitization" was induced by administering increasing doses of acetylsalicylic acid every 24 hr until a good tolerance of 600 mg was obtained. The following day after the ingestion of 600 mg acetylsalicylic acid, 12 patients received 50 mg indomethacin. A good tolerance of 600 mg aspirin was achieved in all examined patients and 50 mg of indomethacin was also well tolerated. The authors assume that mechanism of urticaria and angioedema type of sensitivity to aspirin has the same pathogenic background as aspirin-induced bronchoconstriction.