Solar Urticaria Overview

If you develop a rash after exposure to sunlight, you might be experiencing solar urticaria. The rash can vary from person to person and might include

These symptoms often show up on skin that was newly exposed to the sunlight. Skin that is always exposed, such as the face and hands, might not break out. Also, even though some skin might have been covered by clothing, it can still show these symptoms, too [New Zealand Dermatological Society].

Solar urticaria usually appears within half an hour of exposure to sunlight and typically goes away quickly. If the skin is protected from the sun, the rash should disappear within a few hours and almost always within a day [source: Baron]. If the rash is exposed to more sunlight, it could be dangerous [source: Salford Royal]. In some people, solar urticaria reoccurs and becomes a chronic condition [source: Asthma and Allergy Foundation of America].

People with solar urticaria also might feel sick. Other symptoms can include headache, nausea or fainting [source: Baron]. You should consult your doctor if the rash persists or worsens, or if it covers a large area of your body that was protected by clothing. You should seek medical attention immediately if the rash is accompanied by swelling around your lips or eyes, or if you have trouble breathing or swallowing, or feel faint. These can be serious signs of an allergic reaction and might be symptoms of something other than solar urticaria [source: Harvard Medical School].

Now that you know what to look for, read on to learn how to treat it.

Solar urticaria can be uncomfortable, but there are treatments you can perform at home to reduce the redness and itching. Cool water will help to soothe your irritated skin. Applying cold compresses takes the heat out of the rash, as does a cool soak in the bathtub. Over-the-counter medications, such as antihistamines, can provide even more relief. Ibuprofen, used as directed, can ease the soreness, and anti-itch or hydrocortisone cream can significantly reduce the itching. Before using any over-the-counter medications, be sure to ask your doctor or pharmacist about possible interactions with any prescription medications that you take. Overall, the best thing you can do to treat solar urticaria is to stay out of the sun.

A severe case of solar urticaria requires treatment by a doctor. When home remedies and over-the-counter treatments don't work, your doctor might prescribe a prescription-strength antihistamine and a steroid-based cream [source: Harvard Medical School]. In extreme cases, the doctor will require additional tests and prescribe a treatment that is right for you. Often, this treatment involves phototherapy -- controlled exposure of your skin to sunlight to desensitize your body's allergic reaction to the sun [source: Salford Royal].

Solar urticaria is a rare form of sun allergy. Chances are that hives you get from sunlight are not true solar urticaria. More often, a sun rash is caused by a chemical reaction from a substance on your skin, such as perfume or lotion. Certain medications can also increase your sensitivity to sunlight and cause hives.

Solar urticaria can be difficult to diagnose. If you get a persistent rash from exposure to sunlight, especially if it is severe and accompanied by flu-like symptoms, you should see your doctor. To learn more about solar urticaria, visit the links on the next page.