Photosensitizing drug reactions

Photosensitizing drug reactions are cutaneous eruptions that occur after exposure to ultraviolet radiation in patients using photosensitizing medications. The reactions can be broadly classified into phototoxic and photoallergic, with the former being much more common and well documented. There is an extensive list of photosensitizing medications, especially in the case of phototoxicity. The most common are amiodarone, chlorpromazine, doxycycline, hydrochlorothiazide, nalidixic acid, naproxen, piroxicam, tetracycline, thioridazine, vemurafenib, and voriconazole. Most of the medications implicated in photosensitivity share an action spectrum within the ultraviolet A range. Distinguishing between phototoxicity and photoallergy can be difficult, because some clinical overlap exists between the two disorders. It is often done based on pathogenesis, clinical presentation, and diagnosis. Management is similar for both types of reactions, with the gold standard being prevention. This review provides an overview of the photosensitizing drug reactions and highlights the similarities and differences between phototoxicity and photoallergy, as well as other photosensitizing drug reactions in the phototoxicity family including lichenoid reactions and pseudoporphyria.