Do you find your skin breaking into an itchy rash after spending a few hours under the sun? If yes, you likely have a sun allergy.
While some people have a hereditary type of sun allergy, others develop symptoms when triggered by factors like certain medications and excess sun exposure.
In this article, we explain why some of you tend to develop an allergy to sunlight and effective ways to treat a sun rash. Keep reading for more.
What Expert Says
“Polymorphous light eruption is generally uncomplicated but severe disease can lead to emotional distress, anxiety and depression.”
Dr. Harish Koutam, Chief Dermatologist, SkinKraft
What Is A Sun Rash?
IIf you are allergic to the sun, your skin breaks out into a red, itchy rash, causing a burning sensation. This is known as a sun rash or sun allergy . The rash usually occurs on skin that has been exposed to sunlight, typically the arms, neck, chest, head, and back.
What Does A Sun Rash Look Like?
A sun rash, unlike other allergic reactions, doesn't appear immediately. After you have been in the sun, a sun rash is likely to appear in anything between half an hour, or up to two to three days after exposure to sunlight. A sun rash is not limited to any particular area of the body.
Some Of Its Symptoms Include:
- Red and itchy rashes
- Clusters of blisters or tiny bumps
- Burning sensation on some areas of the skin
- Rough patches of skin
Did You Know?
Often, if someone says they have a sun allergy, they refer to a condition called polymorphous light eruption (PMLE),  also known as sun poisoning. The condition isn't serious, however, it might cause discomfort to your skin.
Why Do You Get Sun Rash?
Prolonged exposure to the sun is one of the primary causes of sun rashes. Some people are photosensitive and are more prone to sun rash. Studies are yet to narrow down on exactly what causes a sun rash. Some experts believe it is the sun's UV rays that cause the skin to react with a rash. In some instances, people who are sensitive to sunlamps or any artificial sources may develop a rash, resulting from an immune reaction.
Factors That Can Make Your Skin More Prone To Sun Rash Include:
- Heredity, when someone in your immediate family has the same condition
- Females are more prone to sun rash than men
- Living in colder parts of the world
- Having very fair skin 
A reaction caused by sunlight on the skin, due to the application of cosmetic products, sunscreens, topical antibiotic ointments, fragrances, and prescribed oral medication, can also cause sun rash. This is known as a photoallergic eruption. 
Dr. Harish Koutam, Chief Dermatologist at SkinKraft says, “Polymorphous light eruption is generally uncomplicated but severe disease can lead to emotional distress, anxiety and depression.” Medication that can cause this kind of sun rash includes diuretics for heart problems and high blood pressure, antibiotics, and painkillers. 
How Do You Treat Sun Rash?
A sun rash doesn’t always require treatment. Sometimes, it can reduce and vanish on its own in a week or two. The kind of rash determines whether it needs treatment. If there is sun poisoning, it will undoubtedly need treatment.
Here are some things you should keep in mind:
- If your rash only itches and there are no blisters or bumps, you can treat it with an OTC ointment that contains hydrocortisone. Anti-allergy tablets or antihistamines also work.
- If you wish to avoid medication, you can shower in cold water or use a cold compress to soothe the itch.
- If the sun rash is in the form of blisters, you can take a painkiller and cover the blisters to avoid scratching or exposing them to infection.
- Applying moisturizer to dry and itchy areas can help soothe the skin.
- If the rash doesn’t subside, it is essential to see a doctor. Prescription medication can reduce and stop symptoms.
- A doctor can also diagnose if the sun rash is an allergic reaction to any medicine that you might be taking for other health issues. In which case, he or she may prescribe corticosteroids to relieve the symptoms.
- Hydroxychloroquine, the drug used for treating malaria, may be prescribed to treat a sun rash as it can relieve some of the symptoms. However, this is not an OTC drug and will require a prescription.
- According to the Vanderbilt University Medical Center, a sunscreen of at least SPF 30 must be used daily.
Precautions To Minimize Sun Rash
- The most crucial step to reduce your chances of sun rash is to avoid overexposure to the sun's UV rays. especially between 10 a.m. and 2 p.m.
- No matter the weather or time of year, wearing sunscreen every day is a must. Apply it at least half an hour before you step out.
- Look for fragrance-free or gently-formulated sunscreens.
- Your sunscreen must protect your skin against both UVA and UVB rays.
- Reapply sunscreen every two hours if you are outdoors.
- If you swim or sweat a lot, reapply your sunscreen at least once every couple of hours.
- Wear hats and loose cotton clothes that cover your arms and legs if you are out in the sun.
- Avoid known triggers such as certain foods or products that you might be allergic to.
- Stay indoors and away from the sun, especially between 10 AM and 4 PM.
- If you have a pre-existing allergy, stretch your time in the sun in a graded manner.
- Herbal supplements like St John's Wort increase your chances of sun poisoning.
- If you apply citrus oil and go out in the sun for long periods, you can get a sun rash or sun poisoning.
- The sunlight reflecting off sand, water, and snow is stronger than on other surfaces. Hence, a day on the beach needs adequate sun protection.
- If you've had treatments like chemical peels done, you are more at risk of sun poisoning.
How Long Does A Sun Rash Last & Can It Spread?
Usually, a sun rash does not last for more than ten days to two weeks . Its duration typically depends on its underlying cause. If you go out in the sun and expose yourself to more UV rays before the rash has completely healed, then yes, it can spread further.
Sun Rash Vs Sun Poisoning
Why Are You Suddenly Allergic To The Sun?
While the exact cause for this is not known, studies have shown that sustained exposure to UV rays may sometimes make the body generate an immune response. This response can be compared to that of pollen in the air or hay fever.
Exposure to the sun may change the skin’s cells in some way, and your immune system will then treat those changed cells as abnormal or foreign and start attacking them, resulting in rash and itching.
A sun rash, in most cases, can be prevented. However, if you do develop an allergy to the sun, it is best to use preventive measures to keep it at bay as much as possible. If it is a severe case of sun poisoning, you need to consult your doctor immediately.
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