Solar urticaria is a rare skin condition that most often affects young women. It is a true sun allergy that involves a response from the immune system. It produces hives on sunlight-exposed skin soon after exposure.

Hives are welts that appear on the skin surface singly or in groups. They can vary in size from as small as a pencil eraser to as large as a dinner plate and may overlap to create large areas of swelling. Hives are itchy and they may also burn and sting. Mild cases of hives are usually temporary and not a threat to a person’s health. However, there may be a recurrence of hives from one local area to another during the same allergic reaction. If hives worsen or persist for several days, the patient should contact a physician.

With solar urticaria, hives usually appear on sun-exposed skin within minutes of exposure. Individual hives typically last for several hours. Though these hives will often disappear without treatment, hives usually return on further sun exposure. Because of the constant threat of recurrence, this condition can be quite disabling and difficult to manage.