FACTORS INFLUENCING METHOXSALEN PHOTOTOXICITY IN VITILIGINOUS SKIN

A series of experiments were conducted to determine the optimum conditions required to induce methoxsalen phototoxicity in [human] vitiliginous skin. Optimum phototoxicity could be obtained only when a lapse of at least 15 min was allowed between the application of the drug and exposure to long-wave UV light (UVA). The duration of methoxsalen''s phototoxic potentiality, after its application to skin, varied in direct proportion to chemical concentration. Although a high chemical concentration and low dosage of UVA was a less time-consuming method of inducing phototoxicity, lower concentration and longer UVA exposure were less likely to induce undesirable blistering reactions.