Phototherapy
If your skin condition can't be controlled by topical treatments, your dermatologist might suggest phototherapy, or light therapy. Ultraviolet light is emitted from the sun and, while it may be invisible to the eye, it can dramatically slow the growth of skin cells, reducing your symptoms. Getting sun is one way of helping your skin. But artificial ultraviolet lamps are a more targeted way of treating the condition.
UVB (Ultraviolet B). While sunlight can help, artificial ultraviolet light can be used with more precision. UVB treatment involves exposing yourself to lights designed to emit the sort of ultraviolet rays that are most helpful. Typical treatment is for three to five days a week for two or three months. UVB treatment may be combined with other approaches.
A newer variety of UVB treatment is called narrow-band UVB, in which the devices are refined to use only the wavelengths of ultraviolet B light that best help psoriasis. Because this approach is more focused, you'll need fewer sessions. As a result, experts believe that any potential risks from the rays are lower.
PUVA (Psoralen plus Ultraviolet A). PUVA uses a different band of ultraviolet light to treat troublesome skin conditions -- ultraviolet A -- in combination with psoralen, an oral or topical medication that makes your skin more sensitive to light. Because this approach uses medication as well as light, PUVA is sometimes called photochemotherapy. PUVA is particularly effective at clearing up severe psoriasis quickly and with long-lasting results, but it has some side effects, including nausea, exhaustion, headaches, burning and itching. Most importantly, using PUVA over a long period of time can increase your risk of skin cancer.
Because psoralen drastically increases your body's sensitivity to light, it's important to protect your skin and especially your eyes after taking it. You should wear glasses that block ultraviolet light for at least 12 hours following treatment.