Modern aspects of phototherapy for atopic dermatitis.

Phototherapy has still great importance in the treatment of atopic dermatitis, though costs, compliance, and long-term risks narrow its relevance. In spite of its long history, up to now, the therapeutic regimes are mostly empirical. Narrowband UVB und UVA1 are the most frequently applied regimens in atopic dermatitis with proven efficacy. However, even for these modalities randomized prospective and controlled studies are still pending. Advances in photoimmunology and molecular biology had demonstrated that phototherapy targets inflammatory cells, alters cytokine production, and has a significant antimicrobial effect within atopic skin. This paper summarizes the current literature on the different regimes of phototherapy and also discusses therapeutic modalities like photochemotherapy and extracorporeal photopheresis. These more complex regimes should be restricted to severe cases of atopic dermatitis, which are refractory to topical treatment.

Regulation of cellular immunity by Photo(chemo)therapy.

Phototherapy and photochemotherapy are important treatment regimens for inflammatory as well as malignant diseases in dermatology. Both treatment modalities have been developed already three decades ago and therefore profound knowledge exists on the use, efficacy, and long-term side effects. Since the development of new mmunosuppressive medications, biologics, and changes in medical reimbursement policies, phototherapy is currently less frequently used compared to previous years to treat psoriasis or atopic dermatitis. However, cost-effectiveness analysis demonstrated that phototherapy can significantly induce therapeutic beneficial effects on a large number of inflammatory and malignant skin disorders at a low cost of treatment rate. Since many chronic skin disorders require rotational treatment regimens to decrease the development of (long-term) adverse events, phototherapy will play an important role in dermatology in future years. In the following the molecular as well as cellular mechanisms of phototherapy are described and discussed in light of the fact that photobiology is a very active field in biomedical research.

Role of immunomodulation in diseases responsive to phototherapy.

Within the last two decades phototherapy has turned out to be a major therapeutic strategy in dermatology and thus has significantly influenced the treatment of many dermatoses. The goals of therapeutic photomedicine are the suppression of ongoing disease processes and, more importantly, the prevention, modulation, or abrogation of pathogenic mechanisms causing the disease. Therapeutic photomedicine has been largely empirical and most of it is still empirical today. However, parts of it are already based on the advances in photoimmunology and molecular biology. Although, we are far from a detailed understanding of the mechanisms underlying phototherapy, there is increasing evidence that phototherapy acts via modulation of the immune system. Most of the effects of both ambient and therapeutic ultraviolet radiation are immunosuppressive in nature.