Sun allergies, also known as photoallergic dermatitis, is an allergic skin reaction triggered by the sun's ultraviolet rays. Completely benign, it usually occurs after the body's first intense sun exposure, and mainly affects women (90%), especially between 15 and 35 years of age.
Small red bumps or blisters accompanied by itching will appear a few hours after sun exposure. These rashes are located on exposed areas of the body: shoulders, arms, legs and chest. However, the face is most of the time left unaffected. Symptoms may persist for several days and resurface with each new exposure to sunlight, but tend to gradually disappear as the skin tans. There are also rarer forms of sun allergies, such as polymorphic light eruption (skin develops red plate lesions, even in low sunlight) or solar urticaria (skin eruptions that occur rapidly after exposure to the sun, then disappear once in the shade).
A regular doctor or a dermatologist can diagnose a sun allergy via a skin examination. If necessary he will make use of phototest (emission of a small amount of ultraviolet rays on the shoulder or back) in order to measure the reaction of the skin to sunlight.
Sunscreen and a measured and gradual exposure to sunlight are the best ways to avoid this unsightly inconvenience. The use of a good sunscreen with a high sun protection is also essential. Finally, the use of dietary supplements such as beta-carotene, associated with eg selenium, vitamins C and E, is advocated by some to strengthen the self-protection capabilities of the skin.