Sun rash, also called a sun allergy, is when a red, itchy rash appears because of exposure to sunlight.

One kind of rash that’s quite common is polymorphic light eruption (PMLE), also called sun poisoning.

Other kinds of sun rash can be hereditary, related to using certain medications, or associated with exposure to irritants like certain plants.

Sun rash typically appears 30 minutes to several hours after sun exposure. Characteristics of the rash can vary, but can include:

  • groups of small bumps or blisters
  • itchy red patches
  • areas of the skin that feel like they’re burning
  • raised or rough patches of skin

If a person also has a severe sunburn, they might be nauseous or feverish.

Someone who has solar urticaria (sun allergy hives), may also feel faint, have trouble breathing, have a headache, and other allergy symptoms.

Sun rash can occur anywhere on the body that’s exposed to sunlight. Some kinds of sun rash occur on skin that’s usually covered in the fall and winter, such as the chest or arms.

While the exact cause of a sun rash isn’t fully known, it’s thought that UV radiation from the sun, or artificial sources like sunlamps, causes a reaction in some people who have a sensitivity to this type of light. This causes an immune reaction that results in the rash.

Some risk factors for certain kinds of sun rash can include:

  • being female
  • having light skin
  • living in Northern areas
  • a family history of sun rash

If you experience a rash after being out in the sun, you should see a doctor to rule out other conditions like contact dermatitis or lupus.

Your doctor can also examine the rash to see what kind of sun-induced rash it might be. If you’ve never had a sun rash before and suddenly get one, call your doctor.

You should get immediate medical attention if your rash is widespread, painful, or if you have a fever. Sometimes sun rashes can mimic other ailments that can be serious, so it’s best to have a medical professional examine you to see what’s going on.

Sun rash isn’t always treated, since many times, it can go away without treatment between 10-14 days. It depends on the specific rash, and if there’s significant sun poisoning or not.

However, if the rash is itchy, an over-the-counter (OTC) anti-itch steroid cream like hydrocortisone can be helpful, as can oral antihistamines, which are also available OTC.

Cold compresses or a cool bath can provide itch relief, as well.

If you have any blisters or if the rash is painful, don’t scratch or pop the blisters. This can lead to infection.

You can cover the blisters with gauze to help protect them, and take an OTC pain relieving medication like ibuprofen (Advil, Motrin) or acetaminophen (Tylenol). As your skin starts to heal, you can use gentle moisturizers to relieve itching from dry or irritated skin.

If home remedies aren’t effective, you might need to see a doctor. They can prescribe you stronger anti-itch cream or oral medication to relieve any symptoms.

If you’re taking any medication, they can let you know if the medication is causing your light sensitivity or rash.

If your sun rash is due to an allergy, your doctor might prescribe anti-allergy medication or corticosteroids to help address any symptoms you might be having. Sometimes the anti-malarial medication hydroxychloroquine is prescribed, since it’s been shown to address symptoms of certain types of sun allergy.

Sun rash often goes away on its own, but can recur with exposure to sunlight.

There are precautions you can take to minimize your risk of having sun rash recur:

  • Wear sunscreen. Apply sunscreen with an SPF of at least 30 about a half hour before going out into the sun, and reapply every two hours (sooner if you go swimming or are sweating a lot).
  • Protect your skin with long-sleeved shirts and a wide-brimmed hat. You might also want to think about wearing specially-made clothes that contain sun protective factors.
  • Avoid the sun between 10 a.m. and 2 p.m., when the sun’s rays are most intense. For extra protection, stay out of the sun until after 4 p.m.
  • If your sun rash is from an allergy, gradually expose yourself to more light in the spring. This might help reduce the likelihood of developing a rash. Work with your doctor to be on the safe side.

Sun rash typically goes away within 10 to 14 days, depending on the underlying cause.

It’s treatable, but in order to prevent it from recurring or to minimize it if it happens again, there are steps you need to take.

If your rash recurs despite precautions, or it doesn’t seem to be improving with treatment, call your doctor.