Fixed Drug Eruptions: An Update, Emphasizing the Potentially Lethal Generalized Bullous Fixed Drug Eruption

A fixed drug eruption (FDE) is a relatively common reaction associated with more than 100 medications. It is defined as a same-site recurrence with exposure to a particular medication. The primary approach and treatment for all types of FDEs are to identify and remove the causative agent, often accomplished by a thorough history of medication and other chemical exposures, and possibly prior episodes. The most common category of FDE, localized FDE, whether bullous or non-bullous, is self-limited. Although one can confirm the causative agent using oral challenge testing, it is not recommended due to the risk of severe exacerbation or possible generalization; patch testing is now preferred. Bullous FDE may resemble erythema multiforme. Treatment of localized FDE includes medication removal, patient counseling, and symptomatic relief. Failure to remove the causative agent in localized FDE can lead to recurrence, which is associated with increased inflammation, hyperpigmentation, and risk of a potentially lethal generalized bullous FDE (GBFDE), which may resemble Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN). Distinguishing GBFDE from SJS and TEN is salient and will be stressed: GBFDE has more rapid onset in 1-24 h rather than in weeks, less or no mucosal involvement, less or no systemic involvement, and a tendency for a more favorable prognosis; however, recent experience suggests it may be just as life-threatening. This review will provide a comprehensive update and approach to diagnosis and management.