Phototherapy includes a variety of ultraviolet light sources for the treatment of benign and malignant skin diseases. One form of phototherapy used at Sand Lake Dermatology Center is PUVA therapy which is used for psoriasis and skin lymphoma. A patient takes a sun sensitizing medicine by mouth and 1-2 hours later receives UVA light. Hand and foot PUVA is used for localized psoriasis and lymphoma as well as chronic dermatitis of the hands and feet. Narrow band ultraviolet B light is also used to treat psoriasis, lymphoma, and a variety of other skin conditions. It is particularly useful in treating vitiligo which is loss of color in the skin.