Action spectrum for UV erythema and reproduction of the skin lesions in hydroa vacciniforme.

Abstract

Action spectra for UV erythema and reproduction of the skin lesions in 4 patients with hydroa vacciniforme (HV) were studied. Vesicles were successfully reproduced by repeated daily monochromatic irradiations of 330, 340, 350 and 360 nm for 5, 6 or 7 days. The daily doses were equivalent to global solar radiation for 70-190 min. The vesicles produced were identical to those of HV, macroscopically and histologically. Repeated daily exposures to a small dose of UVA produced vesicles, whereas a large but single exposure to UVA failed to do so. Daily exposures to UVB failed to produce the vesicles. The minimal erythema dose (MED) was lower than the minimum limits of the normal persons in the 290-310 nm range.