The erythemal response to ultraviolet radiation in subjects with polymorphic light eruption

A reflectance instrument was used to measure objectively the erythemal response to UV-B and UV-C radiation in subjects with polymorphic light eruption. The characteristics of the dose-response curves obtained for each quality of ultraviolet radiation were significantly different, but were essentially indistinguishable from the comparable dose-response curves measured previously in normal subjects. It is concluded that in this photodermatosis the chromophore(s) and mediator(s) of delayed (24 h) ultraviolet-induced erythema are identical to those in normal skin.