Sun allergy is a term often used to describe a number of conditions in which an itchy red rash occurs on skin that’s 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, while others develop signs and symptoms only when triggered by another factor — such as certain types of medications or skin exposure to plants such as limes or wild parsnip.
Mild cases of sun allergy may resolve without treatment. More severe cases may require steroid creams or pills. People who have a severe sun allergy may need to take preventative measures and wear sun-protective clothing.
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.
The appearance of skin affected by sun allergy can vary widely, depending on the disorder that’s causing the problem. Signs and symptoms may include:
- Itching or pain
- Tiny bumps that may merge into raised patches
- Scaling, crusting or bleeding
- Blisters or hives
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.
When to see a doctor
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).