Treatment of parapsoriasis en plaques, mycosis fungoides, and Sézary's syndrome with trioxsalen baths followed by ultraviolet light.

Three patients with parapsoriasis en plaques (PEP), fifteen with mycosis fungoides (MF), and one with Sézary's syndrome (SS) were given a bath to which a small amount of trioxsalen solution had been added, and then exposed to ultraviolet (UV) radiation from a bank of dysprosium lamps. Within 2--6 months of this treatment the skin lesions healed completely or almost completely in all 3 patients with PEP, in all 7 with MF stage II and in 4 of 5 with MF stage III. Two patients with MF stages IV--V showed a fair degree of improvement. One with erythrodermic form of MF responded, but poorly. The patient with SS and the one with erythrodermic MF responded with severe phototoxic reactions.