Is it possible to have a sun allergy? My six-year-old son’s skin breaks out in hives, when he’s exposed to the sun even for a few minutes. Could this be an allergy to the sun? What is it? What are the symptoms? Is there any solution to cure him of this problem or any treatment available?
Dr Chris Foo, Specialist in Dermatology, Raffles Hospital
Yes, sun allergy is possible. The condition is known as solar urticaria. It is an uncommon disorder where hives or wheals are induced by exposure to ultraviolet and/or visible light. Unfortunately the cause is still unknown but it is thought that a chemical present in the body reacts with light, causing an allergic reaction which manifests as hives. It can occur at any age, but is seen most commonly between 20 and 30 years of age. Treatment consists of sunlight avoidance and use of sunscreens. Using sunscreen may offer some protection. Oral antihistamines taken before sunlight exposure may minimise symptoms. Some examples of antihistamines include non-sedating ones such as loratidine or cetirizine. However, most cases resolve spontaneously after a few years even without treatment. The diagnosis needs to be confirmed by phototesting though, so you should bring your son to see a dermatologist for further assessment.