Drug-induced photoallergy.

Over the past several years, the exponential growth in the use of topical and systemic medications and drugs has been accompanied by a concomitant increase in the incidence of adverse reactions associated with them. One type of reaction that has been of particular interest to dermatologists has been the development of immunologic photosensitivity to topically applied and orally administered substances. The majority of agents that have been identified as causing photoallergic reactions in a significant percentage of individuals are no longer utilized. However, because new products are introduced with increasing frequency, this type of photosensitivity disease promises to be an ongoing problem for the dermatologic community.