Drug-induced urticaria and angioedema caused by non-IgE mediated pathomechanisms

Urticaria and angioedema may be elicited by a considerable number of drugs, particularly nonsteroidal antiinflammatory drugs, angiotensin converting enzyme inhibitors, radiocontrast media and antibiotics. Pathogenic mechanisms involved include pseudoallergy, idiosyncrasy and IgE-mediated hypersensitivity, occasionally also IgG antibodies. In this survey the common problems which still lack established diagnostic in vitro tests such as pseudoallergic reactions to analgesic drugs and idiosyncratic side effects to angiotensin-converting-enzyme inhibitors are presented. In addition some examples of drugs are given where, due to progress in research, instead of a pseudoallergic mechanism an immunological pathogenesis could be demonstrated.