Phototherapy of atopic dermatitis with ultraviolet radiation
Studies were conducted in order to evaluate the efficacy of different ultraviolet wavelength regions for the treatment of atopic dermatitis, the risks associated herewith and the in vivo effect of ultraviolet radiation (UVR) on the bacterial skin flora. In bilateral left-right comparisons, adult patients suffering from atopic dermatitis were subjected to treatment with lamps mainly emitting ultraviolet radiation A, UVA, (315-400 nm), UVB (280-315 nm) and combined UVA-UVB, UVAB, respectively. UVAB proved to be most efficacious, with objective and subjective statistically significant superiority to the other types of UVR. UVB was found to be the least efficacious of the three, while the efficacy of UVA was found to lie in between UVAB and UVB. UVAB yielded clearing or considerable improvement in 90% of the patients, while UVA and UVB did so in about 70% of the subjects. Objective differences were less pronounced than subjective ones. The two most common side-effects, xerosis and first-degree burn, were tolerable and clearly correlated to the UVB content of the UVR sources. Uncommon side-effects included polymorphic light eruption (all three types of UVR) and folliculitis (UVB). A typical patient with atopic dermatitis undergoing phototherapy with UVB or UVAB was found to receive an erythemally effective dose of 1 J/cm2 per year, a figure considerably lower than that for UVB-treated psoriasis patients, who, according to previously reported data, receive an annual dose of 4J/cm2. Treatment for 15 years from the age of 25 years will result in an increase in the risk of non-melanoma skin cancer by the age of 60 of 1.15 compared with the risk in untreated individuals. The risks with phototherapy for atopic dermatitis were thus judged to be small. Phototherapy with UVB radiation was shown to possess in vivo antistaphylococcal properties, which were paralleled by clinical efficacy. It is concluded that phototherapy is an effective mode of therapy in patients with mild or moderate atopic dermatitis.