A double-blind study of ultraviolet phototherapy in the prophylaxis of chilblains.

A randomized, double-blind study was carried out to assess the prophylactic value of ultraviolet irradiation in the autumn as a means of preventing the development of chilblains on the toes and fingers during the course of the winter. Placebo irradiation was achieved by means of an optical filter which absorbed all ultraviolet radiation from the lamps but allowed the visible light component to be transmitted, thus giving patients the impression that both limbs were being treated. Patients were reviewed at monthly intervals during the winter. The response between patients was variable; some patients developed chilblains whilst others remained symptom free. However, in no patient did the ultraviolet treated limb differ from the untreated limb. We conclude that the ultraviolet phototherapy is of no value in the prophylaxis of chilblains.