Treatment of psoriasis with 8-methoxypsoralen and sunlight.

Photochemotherapy with 8-methoxypsoralen and sunlight (PUVA-SOL), administered three times weekly, proved effective in the treatment of psoriasis. Weekend photochemotherapy (modified PUVA-SOL) also appeared useful as an adjunct to standard topical corticosteroid therapy. Careful measurement of ambient long-wave ultraviolet light (UVA) in the treatment locale and respect for the phototoxic potential of PUVA-SOL are necessary for success. The long-range toxicity of psoralen photochemotherapy remains undetermined.