Cutaneous reactions to aspirin and nonsteroidal antiinflammatory drugs

Soon after the introduction of aspirin for the treatment of pain, fever, and inflammation more than a century ago, clinicians were challenged by the frequent observation of ASA triggered allergic and pseudoallergic reactions occurring in the skin. This problem was further enhanced by the development of a number of other analgesic and antiinflammatory drugs that, having different chemical structures, cross-reacted with acetilsalycilic acid in many patients. This paper reviews the information presently available for the management of individuals who develop urticaria and angioedema. when exposed to drugs that inhibit cyclooxygenase isoenzymes. The immune and nonimmunologic mechanisms leading to the pathogenesis of such reactions, their prevalence in selected groups of the population, clinical picture, and useful diagnostic approaches are described, and current guidelines used in our institutions for the clinical orientation of the patients, taking advantage of the recent introduction of various new and more selective NSAIDS that inhibit preferentially the COX-2 enzyme, are proposed.