Solar Urticaria Prevention And Treatment

Woman with solar urticaria in sun wearing hat

What is Solar Urticaria?

Solar urticaria (SU) is a rare skin condition characterized by hives, redness, and swelling of the skin. It is considered to be a form of light sensitivity and can result in pain and discomfort. It is caused by exposure to ultraviolet light and sometimes visible light. If you are susceptible you may even develop SU through light clothing. Researchers are not completely sure what causes solar urticaria, but it is believed that it is a type of allergic reaction to sunlight and/or other types of artificial light sources. It is classified as a physical urticaria. You can treat solar urticaria, as well as prevent it.


Symptoms of solar urticaria include intense itching (pruritus), a stinging or burning sensation, redness, and wheal formation (most recognizable as hives). These rashes generally abruptly appear on your skin after as little as 30 minutes of sun exposure; for some individuals they appear in just a few short minutes.

Oftentimes, areas of your skin that are not usually exposed to the sun are the areas that are most affected. For example, your back or legs that are exposed for the first time of the season in the spring or summer may be affected, but not your hands or arms. When large areas of your body are afflicted with solar urticaria, you may even experience vomiting, nausea, headache, and dizziness due to fluid transferring to your skin.

Who is Affected

Solar urticaria is a rare condition and accounts for only 5% of all photosensitivity cases world-wide and 4% of photosensitive patients in the United States. All ethnic groups and skin types can be affected by solar urticaria, and the median onset of age is 35 years. Cases of infants as well as those in their 70’s have been reported. Females are slightly more inclined to develop the condition than males.


Researchers believe that solar urticaria is caused by an antigen-antibody reaction. When some people are exposed to either natural or artificial ultraviolet rays, their bodies create a photoallergen: a chemical that causes an immune response and ultimately produces the urticaria (hives and swelling).

Two types of solar urticaria exist:

  • Type I: An allergic reaction to UV or visible light radiation.
  • Type II: A reaction to contact with another substance including certain dyes, pitch or tar, or medications that contain them, which cause you to be more photosensitive and therefore more susceptible to developing solar urticaria.

How to Diagnose Solar Urticaria

SU can be difficult to diagnose because it is similar to other photosensitivity reactions such as polymorphous light eruption. Even though the symptoms of both are extremely similar, those suffering from solar urticaria are more likely to develop a facial rash.

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There are various definitive ways to accurately diagnose solar urticaria including phototests, photopatch tests, laboratory tests, and photoprovocation tests.

  • A phototest is the most accurate in diagnosing solar urticaria. During this test, you are subjected to differing levels of UVA and UVB radiation on one-centimeter sections of your skin.
  • A photopatch test uses patches applied to your skin: subsequently, you are exposed to low levels of UVA radiation to determine if sunlight is the cause of the allergy.
  • A photoprovocation test is conducted to determine what types of disorders you are prone to when you develop a sunburn. Both UVA and UVB radiation are utilized and if the test results in a rash, a biopsy is performed.

How to Treat Solar Urticaria

If you are susceptible to developing solar urticaria you must take the proper steps to limit your sun exposure. Solar urticaria treatment starts with simply getting out of the sun. After anywhere between a few minutes and a few hours without UV exposure, the hives and swelling begin to decrease and may even go away. Generally, once the rash has disappeared, no tell-tale signs of its previous existence remain on the body.

If you are severely photoallergic, you need to take special steps to prevent future rashes including wearing high SPF sunscreen lotion and covering your body when in the sun. Additionally, oral antihistamines are sometimes helpful when reducing the severity of the rash and itching; however, they don’t normally prevent an outbreak altogether.

If you aren’t able to sufficiently manage your solar urticaria through normal means, you may consider pursuing photochemotherapy and phototherapy options that ultimately desensitize you to UVA and UVB radiation. These types of solar urticaria treatments need to be performed well before the sunny summer months have arrived to maximize the benefits.

How to Prevent Solar Urticaria

The most successful way to prevent solar urticaria is to completely prevent exposing your skin to the sun. Yet even limiting your exposure to sunlight may cause you to significantly alter your lifestyle and may not be altogether possible. Regardless, decreasing your sun exposure is crucial to helping prevent solar urticaria. Here are some suggestions:

  • Always wear protective clothing that shields your skin from sunlight.
  • If possible, make lifestyle changes, including shifting work hours and social activities, to significantly limit daylight exposure.
  • Apply protective UV coatings to glass windows in your home and vehicle.
  • Use, on a daily basis, sunscreen lotion that offers significant SPF protection against UV rays.

Doctors also often recommend antihistamines as a preventative measure. This depends on the severity of the disease, however, and if you are very sensitive and react quickly to sun exposure they won’t help as much as if your body takes longer to develop photo-induced hives.

If you easily and often develop solar urticaria, desensitizing phototherapy treatments are an excellent way to assist your body in tolerating UV rays. However, phototherapy tends to be short-lived and maintenance sessions are required.


Even though solar urticaria is a chronic condition, the prognosis is good. Patients with the disease who adapt to preventative measures often find that they can live fairly normally with the condition. Protective clothing, oral antihistamines, and consistent use of topical sunscreen lotion provide most sufferers with the ability to tolerate some sunlight.

Very few individuals completely overcome the condition. However, even those that experience debilitating symptoms–such as vomiting, headaches, and nausea–can manage the condition with phototherapies.


Solar urticaria is an allergic reaction to natural and/or artificial sunlight. Rashes that involve hives, itching, wheals, and redness may spontaneously appear upon exposure and then begin to disappear once you are removed from the exposure. There are two types of solar urticaria: Type 1 is an allergic reaction caused directly by solar radiation. Type 2 occurs when you are taking another chemical or medication which causes you to be more photosensitive and, subsequently, allergic to UV rays.

Symptoms of solar urticaria include red patches on your skin that are usually raised and itchy. They might burn and sting, and cause other reactions such as headaches, difficulty breathing, a drop in blood pressure, and headache.

SU is a rare condition that affects only about .5% of people worldwide. When looked at on the spectrum of photosensitivity disorders, solar urticaria sufferers make up only 4% of photosensitive patients in the United States (and 5% worldwide). All races and ages can be affected, with women having a slightly higher risk of developing the disease. Median onset is 35 years, but both the elderly and infants can be affected.

Solar urticaria is caused when you produce an antigen while exposed to solar radiation. It may also be caused when you come into contact with outside sources such as pitch, tar, or dyes, or take certain medications that make you more photosensitive.

Diagnosing solar urticaria can be tricky for physicians because it often closely resembles other types of photosensitivity diseases including polymorphous light eruption (PLE). Still, there are various tests that can be undertaken to make an accurate diagnosis. These include laboratory testing, phototests, photopatch tests, and photoprovocation tests. These analyses involve varying levels of UV radiation on your skin.

For many people, treating solar urticaria can be simply a matter of taking antihistamines, limiting sun exposure, and using preventative sunscreen lotions. Treatment can start immediately by seeking shelter from the sun to decrease the severity and number of hives, as well as decrease the burning, itching, and stinging that result from hives.

If you are prone to solar urticaria, you need to think about prevention every day. Liberally using sunscreen lotions and changing your lifestyle to limit sun exposure are possible and successful prevention techniques. For people who need addiitonal help, desensitization to the sun in the form of phototherapy is used to improve the body’s tolerance to UV radiation.

You may also consider taking Sunsafe Rx: a capsule, taken orally, made with antioxidants that research shows support your skin and eyes during exposure to the elements.

The outlook for those with solar urticaria is good. There is no mortality rate associated with solar urticaria, and the largest overall risk is the severity of your allergic reaction. Proven preventative measures and solar urticaria treatment methods can help you manage the disorder so that you can lead a normal, healthy life.