Allergy: mystery of the sun

When in the sun, I get a prickly red rash. It appears anywhere exposed to the sun, but not my face. Even if I stay out of the sun, I still get a rash in hot countries. Sunscreen doesn't help. Is there a solution, short of holidaying in Iceland?

Dr Fred Kavalier answers your health question:

The ultraviolet rays of the sun are causing a reaction in your skin called polymorphic light eruption (PLE or PMLE). This is an allergic-like condition that causes the symptoms you describe. PLE is probably caused by an abnormal reaction of the body's immune system when exposed to UV radiation. The only solution is to stay out of the sun, or you could undergo a course of desensitisation phototherapy or photochemotherapy with a dermatologist. In the spring, you have a series of treatments that increase your skin's ability to withstand UV rays. You don't get a rash on your face probably because you are desensitising your face naturally.

Please mail your questions for Dr Fred to health@independent.co.uk. He regrets that he is unable to respond personally to questions.