Dermatologic drug reactions

Adverse reactions to medications are estimated to occur in 0.1% to 1% of patients using systemic medications. Certain medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, and anticonvulsants, have drug eruption rates approaching 1% to 5% [1]. Approximately 30 drug-related cutaneous reaction patterns are described (Box 1) [2]. In addition, the same medication may evoke a different reaction pattern in different individuals. This fact makes identification of the offending agent difficult for primary care physicians, allergists, and dermatologists. An estimated 2% of medication-related skin eruptions meet the World Health Organization definition of a serious reaction [3]. Of these reactions, several constitute truly life-threatening emergencies and need rapid accurate diagnosis and intervention. This review describes common, serious, and distinctive drug reaction patterns in skin. The pathogenesis of drug allergy is discussed with respect to immunologic mechanisms; nonimmunologic drug reactions may also occur. Basic classification of skin lesions is reviewed; however, this discussion centers on identification of the most common or serious cutaneous reaction patterns.