Comparison of the antipsoriatic efficacy of heliotherapy and ultraviolet B: a cross-over study.

Ten psoriasis patients who underwent a 4-week heliotherapy period in the Canary Islands were treated with ultraviolet B (UVB) phototherapy at relapse, 2-24 months later. In both settings, psoriasis improvement was monitored using a psoriasis severity index (PSI), and UV exposure was recorded with polysulphone films. In the 8 patients that could be evaluated, a median healing rate of 94% was recorded in the heliotherapy period, with a median cumulative UV dose of 46 erythemal units (EU). In the UVB phototherapy, a median improvement rate of 86% was found after a median cumulative UV dose of 112 EU. It is concluded that, on an erythemal UV dose basis, heliotherapy was more effective than UVB phototherapy in treating psoriasis.