Short periods of exposure to the sun reduces psoriasis in most people. Avoid sunburn, which injures the skin and may make psoriasis worse or cause psoriasis to appear on other areas of your skin. Your skin should be examined once or twice a year for skin damage or skin cancer.
Drugs that come in pill, lotion, solution, and ointment forms (such as psoralens and tars) make your skin more sensitive to the sun. Be careful when exposing your skin to sunlight if you are using one of these products. Use sunscreen on areas of your skin not affected by psoriasis.
WebMD Medical Reference from Healthwise