Trioxsalen Bath and Ultraviolet Light Treatment of Psoriasis

To the Editor.— Eighteen light-tolerant patients with widespread psoriasis were treated with 15 minutes of a 37 C warm bath with 50 mg of trioxsalen in 100 liters of water. The trioxsalen added was dissolved in 100 ml of 70% alcohol. Immediately after the bath, the skin was irradiated with a set of lamps for ten to 300 seconds at a distance of 60 cm. 1 The lamp gives 0.8M W/sq cm of ultraviolet (UV)-B and 13M W/sq cm of UV-A. The treatment was given five days per week. One arm was left for treatment with coal tar bath, UV light, and stiff dithranol paste. 2 After two to five weeks, the psoriasis had almost or completely healed on the trioxsalentreated skin. The arm treated with the Ingram regimen 2 healed slower in nine patients, faster in one, and at the same rate in the others. It is possible that