How is psoriasis treated with light (phototherapy)?
Natural ultraviolet light from the sun and controlled delivery of artificial ultraviolet light are used in treating psoriasis. • Sunlight: Much of sunlight is composed of bands of different wavelengths of ultraviolet (UV) light. When absorbed into the skin, UV light suppresses the process leading to psoriasis, causing activated T cells in the skin to die. This process reduces inflammation and slows the turnover of skin cells that cause scaling. Daily short, nonburning exposure to sunlight clears or improves psoriasis in many people. Therefore, exposing affected skin to sunlight is one initial treatment for the disease. It is important to avoid sunburns. Talk to your physician before exposing affected areas to direct sunlight. • Ultraviolet B (UVB) phototherapy: UVB is light with a short wavelength that is absorbed in the epidermis, the outermost layer of skin. An artificial source can be used to treat mild and moderate psoriasis. Some physicians initially will treat patients with UVB i
