Phototherapy arsenal in the treatment of psoriasis.

Ultraviolet light has been the most used and effective treatment of psoriasis over the centuries. Further refinements of the delivery systems for UVB in the form of lasers and localized delivery through fiberoptics are beneficial in helping to reduce the overall exposure of noninvolved skin and permitting more aggressive doses of UV to the sites of disease while sparing noninvolved skin. Enhancement of the different modalities of UVB and psoralen plus UVA has been demonstrated with systemic agents, such as retinoids, but also in combination with immunosuppressive agents for short-term treatment to hasten the initial response to treatment. The advent of the biologic agents in treating psoriasis also introduced the opportunity for combination therapy and the theoretical advantage of managing T cells and antigen-presenting cells in the epidermis with UV light, and activated T cells in the circulation.