Solar phototherapy in dermatological high-altitude climatotherapy

Solar phototherapy for chronic skin diseases, also called dermatological he liotherapy, has a long tradition. Modem dermatological phototherapy by arti ficial ultraviolet (UV) sources originally evolved from heliotherapeutical experience. Nowadays natural solar phototherapy is still performed during d ermatological climatotherapy. A study in the Alexander clinic in Davos, 1,5 60 m above sea level, established low solar UV clearance doses for psoriasi s of cumulative 1,042 J/cm(2) UVB and 41.51 J/cm(2) UVA. Comparably much hi gher UVB doses are needed if using artificial UVB irradiation for psoriasis treatment. The high therapeutical efficacy of natural solar irradiation du ring high mountain climatotherapy could be due to, beside additive effects of various climatotherapeutical factors, particular photoimmunological acti ons of the broad (complete) solar spectrum, possibly also to the special sp ectral distribution of the mountain sun.