Response of psoriasis to psoralen-UVB photochemotherapy

The effect of psoralen in combination with 311 nm (UVB) radiation was studied in five subjects with normal skin and 10 patients with psoriasis involving both forearms. Treatment with oral 8-methoxypsoralen augmented the UVB erythemal response at 6 h after irradiation, but had no effect at 24-72 h. In eight of the nine patients who completed the trial, lesions of psoriasis on the arms treated with psoralen-UVB cleared before lesions on the arms treated with UVB alone. This study has shown that psoralen in combination with UVB has an erythemal effect on normal skin, and a therapeutic effect in psoriasis which is greater than the response to UVB alone.