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, also known as sun poisoning.
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 plants such as wild parsnip or limes.
Mild cases of sun allergy may clear up without treatment. More-severe cases may be treated with steroid creams or pills. People who have a severe 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:
Signs and symptoms usually occur only on skin that has been exposed to the sun and typically develop within minutes to hours after sun exposure.
See a doctor if you have unusual, bothersome skin reactions after exposure to sunlight. For severe or persistent symptoms, you may need to see a doctor who specializes in diagnosing and treating skin disorders (dermatologist).
Polymorphic light eruption occurs most often in areas that are covered in the winter months and exposed in the summer months, such as the front of your neck and chest.
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.
Risk factors for having an allergic reaction to sunlight include:
If you have a sun allergy or an increased sensitivity to the sun, you can help prevent a reaction by taking these steps:
In many cases, doctors can diagnose sun allergy simply by looking at the skin. But if the diagnosis isn't clear-cut, you may need tests to help identify what's going on. These tests may include:
Treatment depends on the type of sun allergy you have. For mild cases, simply avoiding the sun for a few days may be enough to resolve the signs and symptoms.
Creams containing corticosteroids are available over-the-counter and in stronger prescription forms. For a severe allergic skin reaction, your doctor may prescribe a short course of corticosteroid pills, such as prednisone.
The malaria medication hydroxychloroquine (Plaquenil) may ease the symptoms of some types of sun allergies.
If you have a severe sun allergy, your doctor might suggest gradually getting your skin used to sunlight each spring. In phototherapy, a special lamp is used to shine ultraviolet light on areas of your body that are often exposed to the sun. It's generally done a few times a week over several weeks.
These steps may help relieve sun allergy symptoms:
You're likely to start by seeing your family doctor or primary care provider. Or when you call to set up an appointment, you may be referred to a doctor who specializes in skin conditions (dermatologist).
At the time you make the appointment, be sure to ask if you need to do anything in advance. For example, if you're going to have tests that check for a reaction to ultraviolet light (phototesting), your doctor may ask you to stop taking certain medications beforehand.
Before your appointment, you may want to list answers to the following questions:
Your doctor is likely to ask you a number of questions. Examples may include: