Sun Allergy (Photosensitivity) – Harvard Health

What Is It?

A sun allergy is an immune system reaction to sunlight, most often, an itchy red rash. The medical term for this condition is Polymorphous Light Eruption (PMLE). The most common locations include the “V” of the neck, the back of the hands, the outside surface of the arms and the lower legs. In rare cases, the skin reaction may be more severe, producing hives or small blisters that may even spread to skin in clothed areas.  

Sun allergies are triggered by changes that occur in sun-exposed skin. It is not clear why the body develops this reaction. However, the immune system recognizes some components of the sun-altered skin as “foreign,” and the body activates its immune defenses against them. This produces an allergic reaction that takes the form of a rash, tiny blisters or, rarely, some other type of skin eruption.  

Sun allergies occur only in certain sensitive people, and in some cases, they can be triggered by only a few brief moments of sun exposure. Some forms of sun allergy are inherited.  

A few of the most common types of sun allergy are: 

• Actinic prurigo (hereditary PMLE) — This inherited form of PMLE occurs in people of American Indian background, including the American Indian populations of North, South and Central America. Its symptoms are usually more intense than those of classic PMLE, and they often begin earlier, during childhood or adolescence. Several generations of the same family may have a history of the problem. 
• Photoallergic eruption — In this form of sun allergy, a skin reaction is triggered by the effect of sunlight on a chemical that has been applied to the skin (often an ingredient in sunscreen, fragrances, cosmetics or antibiotic ointments) or ingested in a drug (often a prescription medicine). Common prescription medicines that can cause a photoallergic eruption include antibiotics (especially tetracyclines, fluoroquinolones and sulfonamides), NSAID pain relievers ibuprofen (Advil, Motrin and others) and naproxen sodium (Aleve, Naprosyn and others), and diuretics for high blood pressure and heart failure.  
• Solar urticaria — This form of sun allergy produces hives (large, itchy, red bumps) on sun-exposed skin. It is a rare condition that most often affects young women. 

Symptoms

Symptoms vary, depending on the specific type of sun allergy:

• PMLE — PMLE typically produces an itchy or burning rash within the first two hours after sun exposure. The rash usually appears on sun-exposed portions of the neck, upper chest, arms and lower legs. In addition, there may be one to two hours of chills, headache, nausea and malaise (a general sick feeling). In rare cases, PMLE may erupt as red plaques (flat, raised areas), small fluid-filled blisters or tiny areas of bleeding under the skin. 
• Actinic prurigo (hereditary PMLE) — Symptoms are similar to those of PMLE, but they usually are concentrated on the face, especially around the lips. 
• Photoallergic eruption — This usually causes either an itchy red rash or tiny blisters. In some cases, the skin eruption also spreads to skin that was covered by clothing. Because photoallergic eruption is a form of delayed hypersensitivity reaction, skin symptoms may not begin until one to two days after sun exposure.  

Solar urticaria — Hives usually appear on uncovered skin within minutes of exposure to sunlight.

Diagnosis

If you have mild symptoms of PMLE, you may be able to diagnose the problem yourself by asking yourself the following questions:  

• Do I have an itchy rash that occurs only on sun-exposed skin?  
• Does my rash always begin within two hours of sun exposure?  
• Do my symptoms first appear during the early spring, and then gradually become less severe (or disappear) within the following few days or weeks? 

If you can answer “yes” to all of these questions, then you may have mild PMLE.  

If you have more severe sun-related symptoms — especially hives, blisters or small areas of bleeding under the skin — your doctor will need to make the diagnosis. In most cases, your doctor can confirm that you have PMLE or actinic prurigo based on your symptoms, your medical history, family history (especially American Indian ancestry) and a simple examination of your skin. Sometimes, additional tests may be necessary, including:  

• A skin biopsy, in which a small piece of skin is removed and examined in a laboratory  
• Blood tests to rule out systemic lupus erythematosus (SLE or lupus) or discoid systemic lupus erythematosus  
• Photo-testing, in which a small area of your skin is exposed to measured amounts of ultraviolet light — If your skin symptoms appear after this exposure, the test confirms that your skin eruption is sun-related. 

If you have symptoms of a photoallergic eruption, the diagnosis may take some detective work. Your doctor will begin by reviewing your current medicines as well as any skin lotions, sunscreens or colognes you use. The doctor may suggest that you temporarily switch to an alternate medication or eliminate certain skin care products to see whether this makes your skin symptoms subside. If necessary, your doctor will refer you to a dermatologist, a doctor who specializes in skin disorders. The dermatologist may do photopatch testing, a diagnostic procedure that exposes a small area of your skin to a combination of both ultraviolet light and a small amount of test chemical, usually a medicine or ingredient in a skin care product.  

If you have symptoms of solar urticaria, your doctor may confirm the diagnosis by using photo-testing to reproduce your hives. 

Expected Duration

How long the reaction lasts depends on the type of sun allergy:

• PMLE — The rash of PMLE usually disappears within two to three days if you avoid further sun exposure. Over the course of the spring and summer, repeated sun exposure can produce hardening, a natural decrease in the skin’s sensitivity to sunlight. In some individuals, hardening develops after only a few days of sun exposure, but in others it takes several weeks.  
• Actinic prurigo (hereditary PMLE) — In temperate climates, actinic prurigo follows a seasonal pattern that is similar to classic PMLE. However, in tropical climates, symptoms may persist all year round.  
• Photoallergic eruption — The duration is unpredictable. However, in most cases, skin symptoms disappear after the offending chemical is identified and no longer used.  
• Solar urticaria — Individual hives typically fade within 30 minutes to two hours. However, they usually come back when skin is exposed to sun again.  

Prevention

To help prevent symptoms of a sun allergy, you must protect your skin from exposure to sunlight. Try the following suggestions:  

• Before you go outdoors apply a sunscreen that has a sun protection factor (SPF) of at least 30 or above, with a broad spectrum of protection against both ultraviolet A and ultraviolet B rays.  
• Use a sunblock on your lips. Choose a product that has been formulated especially for the lips, with an SPF of 30 or more.  
• Limit your time outdoors when the sun is at its peak — in most parts of the continental United States, from about 10 a. m. to 3 p.m.  
• Wear sunglasses with ultraviolet light protection.  
• Wear long pants, a shirt with long sleeves and a hat with a wide brim.  
• Be aware of skin care products and medicines, especially certain antibiotics, that may trigger a photoallergic eruption. If you are taking a prescription medication, and you normally spend a great deal of time outdoors, ask your doctor whether you should take any special precautions to avoid sun exposure while you are on the drug. 

Treatment

If you have a sun allergy, your treatment must always begin with the strategies described in the Prevention section. These will reduce your sun exposure and prevent your symptoms from worsening. Other treatments depend on the specific type of sun allergy:

• PMLE — For mild symptoms, either apply cool compresses (such as a cool, damp washcloth) to the areas of itchy rash, or mist your skin with sprays of cool water. You can also try a nonprescription oral (by mouth) antihistamine — such as diphenhydramine or chlorpheniramine (both sold under several brand names) — to relieve itching, or a cream containing cortisone. For more severe symptoms, your doctor may suggest a prescription-strength oral antihistamine or corticosteroid cream. If these remedies are not effective, your doctor may prescribe phototherapy, a treatment that produces hardening by gradually exposing your skin to increasing doses of ultraviolet light in your doctor’s office. In many cases, five ultraviolet light exposures are given per week over a three-week period. If standard phototherapy fails, your doctor may try a combination of psoralen and ultraviolet light called PUVA; antimalarial drugs; or beta-carotene tablets.
• Actinic prurigo (hereditary PMLE) — Treatment options include prescription-strength topical corticosteroids, phototherapy with special ultraviolet rays, and potentially thalidomide for severe cases.
• Photoallergic eruption — The first goal of treatment is to identify and eliminate the medicine or skin care product that is triggering the allergic reaction. Skin symptoms usually can be treated with a corticosteroid cream.
• Solar urticaria — For mild hives, you can try a nonprescription oral antihistamine to relieve itching, or an anti-itch skin cream containing cortisone. For more severe hives, your doctor may suggest a prescription-strength antihistamine, a topical or oral corticosteroid preparation, and/or phototherapy..

When To Call a Professional

Call your primary care doctor or a dermatologist if you have:

• An itchy rash that does not respond to over-the-counter treatments
• A rash that involves large areas of your body, including parts that are covered by clothing
• A persistent rash that covers sun-exposed areas of your face, especially if you are a woman or a person of American Indian heritage
• Abnormal bleeding under the skin in sun-exposed areas

Call for emergency help immediately if you suddenly develop hives together with swelling around your eyes or lips, faintness or difficulty breathing or swallowing. These may be signs of a life-threatening allergic reaction.

Prognosis

If you have a sun allergy, the outlook is usually very good, especially if you consistently use sunscreens and protective clothing. Most people with PMLE or actinic prurigo improve significantly within five to seven years after diagnosis, and almost everyone with photoallergic eruption can be cured by avoiding the specific chemical that triggers the sun allergy.

Of all forms of sun allergy, solar urticaria is the one that is most likely to be a long-term problem. However, in some people the condition eventually subsides.

Additional Info

National Institute of Arthritis and Musculoskeletal and Skin Diseases

http://www.niams.nih.gov/

American Academy of Dermatology

http://www.aad.org/

Treatments, Symptoms & Causes – SkinKraft

Reviewed by Expert Prutha B. Nawale (M.tech, Cosmetic Technology)

Updated on April 05, 2022
| Written By Minal Khona

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This blog post is based on scientific evidence, written and fact checked by our doctors.

Our team of dermatologists and formulators strive to be objective, unbiased and honest.

This article contains scientific references. The numbers in the parentheses are clickable links to research
papers from reputed academic organizations.

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

Highlights:

• What Is A Sun Rash?
• What Does A Sun Rash Look Like?
• Why Do You Get Sun Rash?
• How Do You Treat Sun Rash?
• Precautions To Minimize Sun Rash
• How Long Does A Sun Rash Last & Can It Spread?
• Sun Rash Vs Sun Poisoning
• Why Are You Suddenly Allergic To The Sun?

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 [1]. 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), [2] 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 [3]

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. [4]

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. [5]

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 [6]. 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.

Wrapping Up

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.

Begin By Knowing Your Skin

References

1. https://my.clevelandclinic.org/health/diseases/17681-sun-allergy

2. https://www.idoj.in/article.asp?issn=2229-5178;year=2021;volume=12;issue=2;spage=211;epage=219;aulast=Karthikeyan

3. https://www.cancer.org/healthy/be-safe-in-sun/sun-damage.html

4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3063367/

5. https://dermnetnz. org/topics/drug-induced-photosensitivity

6. https://www.nhs.uk/conditions/sunburn/

7. https://dermnetnz.org/topics/polymorphic-light-eruption

8. https://www.skincancer.org/risk-factors/photosensitivity/

Recommended Products

• Exfoliation
• Skin Care
• Skin Disorder
• Skin Type
• Sunscreen

Sunburn – MedSwiss Medical Center

Summer, sun, heat… You just want to lie in the sun, on the banks of the river or on the beach by the sea and acquire a beautiful golden skin tone, which you can show off to your pale-faced colleagues and friends. But here we can expect trouble in the form of sunburn. Sunburn is not only painful, but also unaesthetic, so before going to the beach, you must use sunscreen. When buying a cream, you need to pay attention to the protection factor (SPF) – it can be from 2 to 50, and in modern creams up to 100. When choosing a cream protection factor, it is important to consider the natural color of your skin: the lighter your skin, the more the degree to which it is exposed to the infrared part of the sunlight spectrum, the higher the risk of sunburn and the higher the protection factor of the cream you should prefer. It is recommended to apply sunscreen 30 minutes before sun exposure and then every 2 hours or immediately after swimming. In addition, the time spent on the beach also remains relevant: it is optimal to be in the open sun from 8 am to 11-12 noon, and then from 4 pm.

It is important to remember that prolonged exposure to the sun without the use of protective equipment significantly increases the risk of developing skin cancer (melanoma, squamous cell skin cancer, squamous cell carcinoma), keratosis, and also leads to premature skin aging.

What to do if a sunburn does happen?

First of all, you need to get out of the sun. Then you need to treat areas of damaged skin with soothing creams containing D-panthenol. At the first stage, it can be a spray with D-panthenol, and then a cream with D-panthenol, or Bepanten cream, or Radevit cream. The skin needs to be processed quite often – 3-4 times a day. In the days following the burn, you should avoid direct contact of the burned areas of the skin with the sun’s rays, wear clothes that cover your shoulders and arms. In the future, it is desirable to use sunscreens with higher protection factors.

If the sun’s rays not only had a local effect on the skin, but also led to a violation of the general condition in the form of malaise, rise in body temperature (sometimes up to 39-40C), headache, dizziness, loss of consciousness, i.e. to a condition that is popularly called “sunstroke”, you need to do the following: immediately go into the shade, if the victim cannot leave on his own, then he must be transferred, ice should be applied to the head and large vessels (this is the neck, armpits, groin area) . Plentiful cool is necessary, but not cold! drink. It is advisable to take antipyretic drugs: these are paracetamol drugs (Panadol, Efferalgan, etc.) or non-steroidal anti-inflammatory drugs (Nurofen, Brufen, Nice, etc.). At the same time, you need to take an antiallergic drug – Suprastin, Tavegil, Fenistil, Erius or Zirtek. In case of extensive burns and severe symptoms, you should consult a doctor or call an ambulance team.

Occasionally, a person may develop an allergic reaction to exposure to sunlight in the form of an itchy rash. This condition is called photodermatosis. In this case, it is necessary to take anti-allergic drugs, which we talked about above, and apply anti-allergic creams to the skin – Fenistil gel or Tavegil gel. It is important to follow precautionary measures in the future: use creams with a high protection factor, cover damaged skin areas from direct sunlight.

I would like to remind you that alcohol and sun exposure are incompatible, so you should not drink strong drinks before going to the beach or on the beach.

And finally: now white-skinned and pale-skinned are in fashion. So maybe you shouldn’t try so hard to tan?

Have a good rest!

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Photosensitization – chemical sunburn

The beach season is about to come, which the inhabitants of Latvia, tired of the gray sky, are waiting for with such impatience. Traveling abroad this year is risky, so we can enjoy our own sunny corner more. It sounds very beautiful and romantic, but not everyone has such a friendly relationship with the sun.

Due to various explainable and inexplicable reasons, many of us cannot be in direct sunlight at all. And this beautiful summer may bring not an attractive bronze tan, but a sunburn.

Fair-skinned people have known sunburn since childhood. They know to be extra careful when out in the sun. But not only they can be affected by problems caused by direct sunlight. A perfectly healthy person can also become sensitive to the sun – so that he will receive suffering from it instead of pleasure. This happens with photosensitivity. Photosensitivity refers to an increased sensitivity to light caused by certain chemicals.

The phototoxic effect of sunlight on the skin can become noticeable relatively quickly, after a couple of minutes or hours. Such sunburn is manifested by reddening of the skin, ulceration or even blisters, which in the most serious cases can leave residual scars on the skin.

Types of photosensitivity

What causes this hypersensitivity to sunlight? These can be medicines or some natural foods especially rich in vitamins, body cosmetics and some essential oils. External or internal use of one or more of over 100 different substances can cause sunburn.

Phototoxicity and photoallergy

There are 2 types of chemical photosensitivity: phototoxicosis and photoallergy . With photosensitivity, rashes as a result of a sunburn most often appear on the open parts of our body – the face, neck, décolleté, arms or legs, but there are cases when they cover the skin hidden from the sun.

Phototoxicosis develops pain, redness, sometimes there is a brown or bluish-gray color of those areas of the skin that have been exposed to the sun. Unlike regular sunburn, these skin symptoms appear after taking certain medications:

• antibiotics of the tetracycline group;
• diuretics – diuretic drugs;
• non-steroidal anti-inflammatory drugs such as ibuprofen, paracetamol, etc.;
• retinoids – drugs and medicines that accelerate cell division and skin healing, treat acne;
• antihypertensive drugs – used for high blood pressure;
• psychotropic medicines – for example, antidepressants;
• cholesterol-lowering drugs;
• or after applying chemical substances to the skin – perfume, cologne, tar preparations, essential oils. Some plants containing photocoumarins (lime, lemon, celery, parsley, hogweed, St. John’s wort) also make the skin more sensitive to sunlight.

All phototoxic reactions occur only on areas of the skin exposed to the sun. Sunburns usually appear within a couple of hours after exposure to the sun.

Photoallergy is a type IV late allergic reaction that causes skin redness, peeling, itching, and sometimes blisters. Shaving lotions, sunscreens, and other topical cosmetics can cause this sunburn reaction. Photoallergic reactions can also occur on skin that has not been exposed to direct sunlight. Rashes appear later than with phototoxicosis – from 24 to 72 hours after exposure to the sun.

This is a slightly more complex reaction because the body also uses the immune system. The body mistakenly “thinks” that the combination of sun and medication is a threat and starts to defend against it, generating sunburn-like rashes.

It should be added that sometimes these reactions can pass one into another or even be present at the same time. In any case, the best therapeutic and prophylactic remedy is protection from direct sunlight. About what other measures should be taken, I will tell at the end of the article.

How does this body reaction actually develop?

Redness of the skin caused by sunburn is due to vasodilation. When this happens, biologically active substances are released from the vessels, triggering the process of inflammation: there is swelling, a burning sensation or soreness, which can turn into a feeling of pain. The affected area becomes hotter compared to skin that is not affected by inflammation. As a result of this process, one layer of skin separates from another and blisters form – a rash, ulceration or blisters.

How do you know if a rash has appeared under the influence of medicines or cosmetics?

If you have been in the sun recently and your skin has become red and gradually feels irritated, it could be phototoxicosis or photoallergy. If you’ve been in the sun long enough and the redness is noticeable in the exact areas you’ve been exposed to the sun, it could be just a sunburn. But if the reddened areas are small and you feel a burning sensation, this may be due to photosensitivity.

People say: to determine whether the rash is due to photoallergy or phototoxicosis, you need to press hard with your finger on the reddened area. If it becomes pale, it is a photoallergy. And then, most likely, the matter is in the chemicals applied to the skin.

If nothing changes, it is phototoxicosis, and then the cause may be medicines or food. However, as a specialist, I do not recommend this method, since you cannot rely on it 100%. In such cases, it is better to consult an experienced dermatologist.

What should I do if I get a sunburn caused by photosensitivity?

• Avoid further sun exposure;
• Discontinue the drug responsible for the photosensitivity (if possible). And within a couple of days after the withdrawal of the medication, it is still not worth being in the sun;
• Think about cosmetics for the body. Do not use chemicals of poor quality. Sunburns from light can also be caused by undistilled essential oils;
• Use sunscreen with an SPF of at least 50 before sun exposure.