[New aspects of UV-therapy of atopic dermatitis]

Atopic dermatitis (AD) is a familial inflammatory skin disease characterized by a typical morphology and distribution and a chronically relapsing course with frequent periods of exacerbation. The management of AD is primarily directed towards symptomatic relief, and treatment decisions depend on cutaneous symptoms at any given time. During periods of acute exacerbation, therapy consists almost exclusively in topical or even systemic corticosteroid therapy. Since long-term corticosteroid therapy is known to have a variety of side-effects, it is important to develop alternative modalities for treatment of AD, such as phototherapy with ultraviolet radiation (PUVA, UV-B, UV-A-B). The major disadvantages of PUVA therapy are the relatively high number of treatments required for healing, the high frequency of rebound phenomena, and as a long-term effect, the potentially increased risk of skin cancer. In contrast, UV-B/UV-A-B therapy is not associated with any major side-effects, but its beneficial effects are clearly limited and usually require several weeks of treatment. Therefore, UV-B/UV-A-B therapy is mostly used in combination with corticosteroids for the treatment of acute AD to increase the therapeutic effectiveness. Very recent data indicate that a monotherapy with pure UV-A (340-440 nm) light, if applied in higher doses (15 x 130 J/m2; High-Dose UV-A1), is very effective in the treatment of patients with acute AD. Examination of the photoimmunological events underlying the observed therapeutic effectiveness of High-Dose-UV-A1 therapy may help us to understand the pathophysiological events relevant for AD.