Allergies Allergy Basics

Are You Allergic to the Sun?

By Christine Haran

Although die-hard sun worshipers continue to oil up to better catch the sun's tanning rays, most Americans choose to slather on sunscreen instead. Sunscreen can help protect them from most of the harmful effects of ultraviolet light, but it will do little for certain sun-sensitive individuals. These would-be sun seekers wind up with an itchy, bumpy rash that is sometimes called "sun poisoning" even if they're wearing SPF 50.

"Sun poisoning" is really an allergic reaction to the sun that occurs when skin is exposed to sunlight for the first time in the early spring, or during a winter vacation. While people with light skin are most susceptible to sunburn, sun allergy affects people of all skin colors.

If people with sun allergy venture to the beach at all, you can probably find them in a floppy hat, under an umbrella. Or, at least, that's where they should be. Below, Henry W. Lim, MD, chair of the department of dermatology at Henry Ford Hospital in Detroit, Michigan, talks about how to prevent and treat allergic reactions to the sun, as well as rashes triggered by sunscreen ingredients.

Can someone have a sun allergy?
There are certain skin reactions to the sun that have nothing to do with sunscreen or other external factors, which we call an intrinsic type of photodermatosis. People with photodermatosis develop skin rashes following exposure to the sun. Polymorphous light eruption is the most common type of photodermatosis. It is most likely due to an abnormal immune system reaction to the sun. Polymorphous light eruption occurs in approximately 10 to 20 percent of otherwise healthy individuals, so it is a relatively common condition.

Then there is another group of people who develop what they think is a sun allergy because of medications that they have ingested or agents that they have applied, including sunscreen. These people develop an irritant reaction, which is a rash or a tingling, itchy sensation on the skin. The chances of getting a true allergic reaction to sunscreen are actually very low.

What are the symptoms?
People usually develop reactions within a few hours of sun exposure. The typical scenario would be that they get exposed to the sun during the day, and then at the end of the day they start noticing the development of red bumps or blisters in the exposed area. It tends to be somewhat itchy. The polymorphous light eruption produces a rash that looks more like hives or insect bites. Sometimes people have no symptoms. If the reaction is untreated, it usually lasts for a few days, or up to two weeks. Then it would go away by itself.

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