Abstract
Phototoxicology deals with the injurious effects of ultraviolet and visible radiation. The principal phototoxiceffectis the erythema, edema, and pain (“sunburn”) produced in unacclimatized skin by exposure to solar radiation. Similarly, pho-tokeratitis (“snow blindness”) is a phototoxic phenomenon which was described as early as 410 BC by Xenophon. That it was ultraviolet radiation that was the proximate cause of these photo-toxic effects was discovered by Charcot (1858) in experiments with electric arcs. Dubreuilh (1896) related outdoor solar exposure to incidence of skin cancers; and in 1899, Raab noticed that fluorescent chemicals could be activated by visible light to produce killing of microorganisms. By the middle of the twentieth century, phototoxic effects, primarily on skin, were discovered to be due to in trinsic and to topically applied materials (e.g., porphyrins, coal tar). The phototoxic effects of medicinal compounds (e.g., fluoroquinolones), have recently become important. Photoactive agents and their phototoxic effects have long been used in the therapy of such skin diseases as vitiligo and psoriasis, and more recently for the treatment of malignancies.