ABSTRACT
Cutaneous photosensitivity induced by exogenous agents is a well-documented phenomenon. It is defi ned as an undesirable pharmacological effect that occurs upon simultaneous exposure to photosensitizing chemical or drug and radiation of the appropriate wavelength. Drug-induced phototoxicity is classifi ed as either phototoxic or photoallergic. Multiple chemicals, such as psoralens, fl uorescein dye, some thiazide diuretics, and some fl uoroquinolones are able to produce both types of cutaneous reactions. It may be diffi cult to distinguish between these entities, however, they are pathophysiologically distinct processes.
