Although both UVB and ultraviolet light A (UVA) are found in sunlight, UVB works best for psoriasis. UVB from the sun works the same way as UVB in Psoriais phototherapy treatments.Short, multiple exposures to sunlight are recommended. Start with five to 10 minutes of noontime sun daily. Gradually increase exposure time by 30 seconds if the skin tolerates it. To get the most from the sun, all affected areas should receive equal and adequate exposure. Remember to wear sunscreen on areas of your skin unaffected by psoriasis.Avoid overexposure and sunburn. It can take several weeks to see improvement. Have your doctor check you regularly for sun damage.
Some topical medications can increase the risk of sunburn. These include tazarotene, coal tar, Elidel (pimecrolimus) and Protopic (tacrolimus). Individuals using these products should talk with a doctor before going in the sun.People who are using PUVA or other forms of light therapy should limit or avoid exposure to natural sunlight unless directed by a doctor.
Psoralen + UVA (PUVA)
Like UVB, ultraviolet light A (UVA) is present in sunlight. Unlike UVB, UVA is relatively ineffective unless used with a light-sensitizing medication psoralen, which is administered topically or orally. This process, called PUVA, slows down excessive skin cell growth and can clear psoriasis symptoms for varying periods of time. Stable plaque psoriasis, guttate psoriasis, and psoriasis of the palms and soles are most responsive to PUVA treatment.
The most common short-term side effects of PUVA are nausea, itching and redness of the skin. Drinking milk or ginger ale, taking ginger supplements or eating while taking oral psoralen may prevent nausea. Antihistamines, baths with colloidal oatmeal products or application of topical products with capsaicin may help relieve itching. Swelling of the legs from standing during PUVA treatment may be relieved by wearing support hose.