Home Health A-Z Sun Allergy – Types, Causes, Symptoms, Disgnosis and Treatment

Sun Allergy – Types, Causes, Symptoms, Disgnosis and Treatment

Verified By Apollo Dermatologist May 18, 2022 5849 0
Sun Allergy
Sun Allergy


A sun allergy is most commonly used to describe several skin conditions wherein an itchy rash, blister, or hives occur on the sun-exposed part of the skin. It is usually seen in people with sun sensitivity and most often occurs during spring and early summer. This article dives deep into the different aspects of sun allergy, types, causes, symptoms, treatment, and associated risk factors. 

What is a sun allergy?

Sun allergy is a result of the immune system’s reaction to sunlight. This reaction can occur after prolonged exposure to the sun or may crop up even after an exposure which lasts for a shorter interval. The immune system reacts the skin is exposed to the sun. Thus, the body activates the immune defence mechanism against it, resulting in rashes, blisters, or hives. The polymorphic light eruption, commonly known as sun poisoning, is the most common form of sun allergy.

Sometimes, hereditary traits play a crucial role as this allergy could be passed on from parents to children. It may also be triggered due to external factors such as medicines or exposure to certain plants such as wild parsnip or limes.

Individuals with mild symptoms may not require any medication. But those experiencing moderate to severe reactions may need to take medications, or other preventive measures, or wear clothing that protects them from the sun.

What are the different kind of sun allergies?

Here is a ready list of the most common types:

  1. Actinic prurigo: A person inherits this kind of sun allergy. This begins in childhood, and the resultant symptoms are stronger than other types. 
  2. Photoallergic reaction: When an individual uses a certain medication, cosmetics, and fragrances, it reacts with the sun causing a photo allergic reaction. Sometimes, symptoms may not occur immediately – they may show up after two to three days. 
  3. Polymorphic light eruption (PMLE): This is the most common form of sun allergy, occurring more often in women than in men. It usually starts in the teens and twenties. PMLE usually manifests in the form of itch causing rashes and can appear as blisters or small reddened areas. Symptoms usually appear a few hours after exposure to sunlight.
  4. Solar urticaria: This sun allergy is rare and mostly affects young women. Hives can be seen after a few minutes of sun exposure. Symptoms can be mild or severe or can also cause anaphylactic shock, which is a life-threatening allergic reaction.

What are the symptoms of sun allergy?

The symptoms of sun allergy can vary widely, depending on the cause of the problem. Signs and symptoms may include redness, itchiness or pain, tiny bumps that may merge into raised patches, blisters or hives, and scaling, crusting, or bleeding.  

  • Actinic prurigo: Individuals experience very itchy, crusted bumps (nodules).
  • PMLE and photoallergic reaction: In this, within two hours of sun exposure, the person may get a burning or itchy rash and fluid-filled blisters. 
  • Solar urticaria: Individuals notice hives a few minutes after sun exposure. At first, a burning and stinging sensation may occur. The rashes fade slowly over days or weeks. Sometimes, the skin may darken after the reaction.

Signs and symptoms usually occur only on skin that has been exposed to the sun and typically develops within minutes to hours after sun exposure.

How is a sun allergy diagnosed?

The health care provider can often diagnose a sun allergy only by looking at the skin. To help identify the reasons which instigated the allergic reaction, doctors may also require family history and other tests for a correct diagnosis. The tests may include the following:

  1. Photo patch testing: This checks if the skin reacts to sensitizing substances in the sunlight.  A medical practitioner applies common sun allergy triggers directly on the skin, usually the back. After a day, measured doses of ultraviolet rays are emitted from a sun lamp to find if a reaction occurs in the light-exposed area. If yes, then the substance is likely triggering the sun allergy.
  2. UV light testing: The test enables the doctors to see how the skin reacts to different wavelengths of UV light and helps pinpoint the exact allergens.
  3. Blood tests and skin samples: These are only required if the doctor suspects underlying conditions such as lupus that might be causing sun allergies. 

What are the causes of sun allergy?

It is difficult to ascertain why certain people develop sun allergy, while others don’t. Sometimes, genes play a crucial role. For others, certain medications, chemicals, and medical conditions may increase skin sensitivity to the sun.  

What are the risk factors?

The following are the possible risk factors associated with the allergic reaction to sunlight:

  1. Race: The race of a person plays an important role in the possibility of developing a sun allergy. Certain sun allergies are common in lighter skinned individuals. 
  2. Reaction to certain substances: Sometimes, symptoms are triggered when the skin is exposed to certain substances and sunlight, at the same time. The common substances include perfumes, disinfectants, and certain chemicals in the sunscreen.
  3. Consumptions of certain medications: Some medications can cause the skin to react to sunlight . These medications include tetracycline antibiotics, sulfa-based drugs, and pain relievers such as ketoprofen.
  4. Diagnoses of other skin conditions: People with Dermatitis have a high chance of developing a sun allergy.
  5. Runs in the family: A person is more likely to get sun allergy if parents and siblings are also diagnosed with the same disorder.

How to treat and manage a sun allergy?

A sun allergy reaction can occur anywhere on the body, but it is mostly found on exposed areas such as the arms, legs, hands, and the back of the neck. In severe cases, areas protected by clothing may also get affected. 

Treatment is carried out depending on the kind of sun allergy. Usually in mild cases, avoiding sun exposure for a couple of days may resolve the signs and symptoms. Other treatment options include:

  • Medications: Creams or medications
  • Therapy: Phototherapy gradually helps the skin get accustomed to the sunlight. 

If a person experiences sun allergy or increased sensitivity to the sun, managing it is easy with the following steps: 

Stay indoors during the hours of maximum sun exposure  

  1. Use sunscreen greater than SPF 30. 
  2. Consult with a dermatologist to get the best course of treatment for sun allergy.
  3. Use sunglasses and wear protective clothing.

What are the steps to prevent sun allergy?

  1. Avoid stepping out during peak sunlight hours: Staying indoors between 10 am to 4 pm helps in combating sun allergy.
  2. Use protective gear: Wearing sunglasses, applying sunscreen, using hats and thick clothes can help in protecting the skin from sun exposure. Avoid thin and breathable fabrics as UV rays can easily penetrate causing skin allergies.
  3. Apply sunscreen: It is important to apply a broad-spectrum sunscreen with an SPF of at least 30 or more. Keep in mind to generously apply sunscreen and reapply every two hours if swimming or continuously sweating. 
  4. Avoid sudden exposure to too much sunlight: When people with sun allergies are suddenly exposed to more sunlight during summer and spring, they may experience mild or severe symptoms. In such cases, gradually increasing the amount of time spent outdoors helps skin cells adapt to the sunlight.
  5. Prevent known triggers: Certain medications and substances cause skin reactions. If an individual is aware of them, then it is advisable to avoid them.


Sun allergies, hereditary or otherwise, when managed and treated properly help a person lead a normal life. It is best to always ask a doctor before consuming any medications. 

Frequently Asked Questions:

What is the difference between a sun allergy and other skin conditions?

A sun allergy causes a similar kind of skin irritation as other conditions. Sun allergies generally occur after the skin exposure to the skin. 

What are the symptoms of anaphylaxis?

Watch out for symptoms such as:

  1. Itchiness and tightness around the throat
  2. Vomiting, diarrhoea, cramping in the stomach
  3. Difficulty in breathing and coughing and wheezing
  4. Weak pulse
  5. Dizziness and decreased blood pressure
  6. Generalised hives and swelling beneath the skin

What is the duration of the symptoms of the skin allergy?

The symptoms may last for a few days and may occur again after the next sun exposure.

Verified By Apollo Dermatologist
The content is carefully chosen and thoughtfully organized and verified by our panel expert dermatologists who have years of experience in their field. We aim to spread awareness to all those individuals who are curious and would like to know more about their skin and beauty

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