Solar urticaria

What is solar urticaria?

Solar urticaria is a rare condition in which exposure to UV light/radiation produces hives (urticaria). It is difficult to diagnose properly as symptoms can be very similar to other dermatological conditions. However, it can be identified through phototesting.

What are the symptoms of solar urticaria?



Generally the areas affected by hives are those which are exposed to sunlight (i.e not covered by clothing). Initially, the first sign is pruritis (itching), which then progresses to redness forming on the skin (erythema), and oedema, an accumulation of fluid, i.e swelling. This can happen within minutes of exposure, making life difficult for those who experience the condition. If a large area of the body is exposed then the risk of anaphylactic reaction is increased.

What are the causes of solar urticaria?

Solar urticaria occurs due to a mechanism of immediate hypersensitivity to an unknown allergen produced by sunlight. It is not yet understood which agent in the body causes the allergic reaction to sunlight.

Can solar urticaria be prevented?

The most effective way of preventing solar urticarial is to avoid sun exposure. Take preventive measures in order to minimise exposure:

  • Wear a hat or cap
  • Wear protective clothing which shields the skin from sunlight
  • Wear sun cream on a daily basis, which offers significant UV protection
  • Re-apply sun cream every two hours
  • Install UV-protection on glass, such as in the car and in the home
  • Take medication, but only when advised by a specialist

What is the treatment for solar urticaria?

While solar urticaria cannot necessarily be cured, its symptoms can be managed and over time a certain tolerance to UV light can be built. Forms of desensitization treatment now exist, including phototherapy and photochemotherapy, which gradually build up the exposure to the radiation causing the reaction.

Your specialist may recommend medication to control urticaria symptoms, and medication is prescribed on a case by case basis.

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