In-Vivo-UVA-Tests: Erythema, Pigmentation, Phototoxicity

The time course and dose requirements for the effects of UV-B-irradiation on human skin are well characterized. Since 1931, when Wucherpfennig [13] introduced the “Lichttreppe”, this classical test has been used to determine sensitivity to UV-Berythema. Skin responses to UV-A, however, are less well and only qualitatively defined. Studies aiming at quantification of UV-A-effects are few [2, 4, 6, 8, 11]. They have been hampered by lack of suitable light sources. In 1977 a new apparatus with high radiation energy between 320–460 nm was introduced; a description of the appatus and its dermatological applications was published in 1981 [7]. Advantages of the device are high intensity in the UV-A-range with virtually no additional UV-B and the possibility or irradiation of large areas of the skin surface.