Solar urticaria is a type of urticaria or hives which is triggered by exposure of the skin to sunlight or UV light. It is an uncommon condition.
The rash of solar urticaria is the same as the rash of common urticaria or hives, presenting with itchy red wheals over the sun-exposed areas. The rash usually occurs shortly after sun exposure and settles with minutes or hours when away from the sun. In a study looking at solar urticaria in patients from Singapore, it was found that the triggering wavelength was most commonly by the visible light and UVA radiation spectrum.
Treatment of solar urticaria includes sun protection and avoidance. Oral antihistamines are effective in controlling the rashes and hives. In some cases, phototherapy can be used to 'toughen' the skin to sunlight, to increase to skin's tolerance to sun exposure.
