Light Therapy (Phototherapy)
Light therapy involves using ultraviolet light to slow the rate of skin-cell growth and relieve symptoms. For moderate psoriasis, UVB light therapy may be combined with creams or ointments. Regular, brief exposure to natural sunlight, or ultraviolet light from an artificial source, seems to help kill inflammation-causing cells in the skin.
Lasers are being used with some success, but long-term studies have not been completed. The excimer laser, which targets small areas with a high-intensity light similar to UVB, has been approved by the FDA for psoriasis treatment. Pulsed dye lasers use a different kind of light to zap the blood vessels supplying developing lesions. Both types of laser treatments have been approved for psoriasis treatment by the FDA.
When psoriasis is moderate to severe, a potent form of light therapy known as PUVA may be tried. This treatment combines use of an oral or topical, light-sensitizing drug called psoralen -- the P in PUVA -- with exposure to UVA light. The American Academy of Dermatology reports that PUVA has been effective for 85% of people with psoriasis. The one catch: Ultraviolet light treatments, especially PUVA, must be used conservatively, because they age the skin and elevate skin cancer risk.
