Understanding Sun Allergy

Solar urticaria, commonly referred to as sun allergy rash, is a rare dermatological condition in which the areas of the skin, whether covered or uncovered, swell and experience urticaria or hives after exposure to natural sunlight or an artificial light source that emits ultraviolet radiation.

People with this form of chronic inducible urticaria often develop scratchy, red rashes upon minutes of exposure to UV rays. The reaction usually eases up within a few minutes, but some cases may persist for up to an hour or more, causing pain, distress, and embarrassment if untreated.

At what age does it occur? The British Association of Dermatologists (BAD) explained that individuals aged between 20 and 40 are the most affected by solar urticaria. Some people have a hereditary type of sun allergy while others develop signs and symptoms only when triggered by medication or other factors.

According to Mayo Clinic, the appearance of skin affected by sun allergy can vary widely, depending on what’s causing the problem. Signs and symptoms may include:

  • Redness
  • Itching or pain
  • Tiny bumps that may merge into raised patches
  • Scaling, crusting, or bleeding
  • Blisters or hives

However, the BAD also noted that rare cases of solar urticaria may be accompanied by other symptoms such as headache, nausea, vomiting, breathing difficulties, and low blood pressure.

While these symptoms normally subside, the majority of cases persist. When the symptoms do not go away easily, treatments such as desensitization, dietary changes, and taking antihistamines and Immunosuppressant drugs may provide control by reducing the appearance and symptoms of the solar urticaria.

Treating solar urticaria can be difficult, especially if it is visible light causing the problem. Fortunately, you can take different measures to prevent its occurrence. Here are 4 things you can do to prevent or reduce your risk for solar urticaria.


The best way to avoid getting solar urticaria is to limit your sun exposure. According to reports, the sun seems to be the strongest between 10 a.m. and 4 p.m., so make sure to spend time in the shade.

Also, as advised by Healthline, consider phasing in your outdoor time in the spring by gradually increasing the time you spend outdoors to help your skin cells adapt to the stronger summer sunlight.


Applying a broad-spectrum sunscreen when spending time under the sun can help protect the skin from the harmful effects of the sun. The BAD explained that reflectant sunscreens that are based on titanium dioxide or zinc oxide will be more effective as they cover UVA, UVB, and visible light.


Despite the hot weather, your skin still needs moisturizer.

As reported by GQ, moisturizer hydrates your cells, promotes healthy turnover, and creates a barrier over your skin to protect it from environmental wear. MayoClinic also explained that applying moisturizer can help relieve irritation caused by dry, scaly skin.


Even though you have your skin covered by clothes, solar urticaria may still develop if you’re wearing garments made with thin fabric.

The BAD recommends wearing clothing pieces made from tightly woven fabrics and pieces that have more coverage on the skin, such as long sleeves. Using dark clothes can also help absorb more UV rays, preventing them from reaching your skin.

When running errands, use brimmed hats, umbrellas, and other items that can give you shade. When driving under the heat, put on gloves and wear shoes rather than sandals.


The information presented on AllergyKB is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Our knowledge base website is for general informational purposes only. It should not be construed as a standard of care to be followed by a user of the website. We highly urge everyone to always seek the advice of their physician or other qualified health providers.

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