[Quantitative assessment of heliotherapy in psoriasis vulgaris in high altitude climate].

At the Davos Clinic for Dermatology and Allergy (Alexanderhausklinik), patients suffering from psoriasis were treated with natural UV irradiation over 6 weeks in 1987: the average doses applied amounted to 1.042 J/cm2 UVB (= 41.7 sunburn units (SU] and 41.511 J/cm2 UVA. These doses were far below those of artificial UV sources usually required in the treatment of psoriasis. The doses were also far below those which statistically increase the incidence of non-melanotic skin cancer.