Allergy and adverse drug reactions.

This review begins with a classification of adverse drug reactions and a summary of those features that distinguish allergic from toxic and idiosyncratic reactions. Factors that influence the risk of developing drug allergy are then reviewed, followed by a discussion of the known and suspected immunologic mechanisms responsible for the development of drug allergy. The next section-on the types of clinical reactions-begins with the reactions that are mediated, or suspected of being mediated, by antibodies of the immunoglobulin E class. These are followed by a description of reactions involving single organ systems and those involving several systems. The next section reviews the cutaneous reactions that are sometimes due to drug allergy, and those that may be mistakenly blamed on drug allergy. This is followed by a discussion of pseudoallergic drug reactions-caused by toxicity or side effects of some drugs. The review concludes with a discussion of the prevention and treatment of reactions that are allergic or commonly suspected of being allergic.