• Sun allergy is a term often used to describe a number of conditions in which an itchy red rash occurs on skin that has been exposed to sunlight. The most common form of sun allergy is polymorphic light eruption.
• Some people have a hereditary type of sun allergy. Others develop signs and symptoms only when triggered by another factor — such as a medication or skin exposure to some plants.
• Mild cases of sun allergy may clear up without treatment. More-severe cases may be treated with creams or pills. People who have a sun allergy may need to take preventive measures and wear sun-protective clothing.
The appearance of skin affected by sun allergy can vary widely, depending on what's causing the problem. Signs and symptoms may include:
• Redness
• Itching or pain
• Tiny bumps that may merge into raised patches
• Scaling, crusting or bleeding
• Blisters or hives
Certain medications, chemicals and medical conditions can make the skin more sensitive to the sun. It isn't clear why some people have a sun allergy and others don't. Inherited traits may play a role.
If you have a sun allergy or an increased sensitivity to the sun, you can help prevent a reaction by taking these steps:
• Avoid the sun during peak hours. Try to stay out of the sun between 10 a.m. and 4 p.m.
• Avoid sudden exposure to lots of sunlight. Many people have sun allergy symptoms when they are exposed to more sunlight in the spring or summer. Gradually increase the amount of time you spend outdoors so that your skin cells have time to adapt to sunlight.
• Wear sunglasses and protective clothing. Long-sleeved shirts and wide-brimmed hats can help protect your skin from sun exposure. Avoid fabrics that are thin or have a loose weave — UV rays can pass through them.
• Use sunscreen. Use a broad-spectrum sunscreen with an SPF of at least 30. Apply sunscreen generously, and reapply every two hours — or more often if you're swimming or perspiring.
• Avoid known triggers. If you know that a certain substance causes your skin reaction, such as a medication or contact with wild parsnip or limes, avoid that trigger.