The importance of patient selection for photochemotherapy in psoriasis.

Twenty-four patients with psoriasis were treated with orally administered 8-methoxypsoralen followed by exposure to high-intensity long-wavelength ultraviolet radiation (PUVA) at a psoriasis day care centre. Among the 20 with plaque type psoriasis the condition cleared in 13 (65%), after a mean of 20.7 treatment sessions, and improved but failed to clear in 4 (20%); the treatment failed in the other 3 (15%). The other four patients had erythrodermic, pustular or inflammatory psoriasis, and all failed to respond to PUVA therapy. Factors to be considered in patient selection for this form of therapy are the type of psoriasis, the patient's skin type and th proportion of the body surface area involved.