Around 1 in 5 people experience an itchy, red rash from sun exposure.

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Take steps to protect your skin when enjoying the sun this summer. Getty Images

Even though the sun is almost 93 million miles away, it can have profound effects on our skin. Just a few minutes spent soaking up the rays is enough to cause a sunburn. Over a lifetime, sun exposure can also cause wrinkles, skin spots, and cancer.

But if that wasn’t enough of a reason to keep your skin covered this summer, here’s another health issue that can be caused by that flaming ball of plasma: sun allergy.

No, it’s not some fictional condition. Sun allergy is a term that describes when the skin breaks out into an itchy red rash after a person spends time outdoors.

Here’s what people need to know about this condition, how to tell the difference between sun allergies and sunburn, and tips to protect your skin when spending time outdoors.

Polymorphic light eruption, the medical term for a sun allergy, is a condition in which the skin experiences adverse reactions to sun exposure.

It typically shows up as an itchy, red rash, but a sun allergy can also cause pain, raised patches of skin, scaling, blisters, hives and other symptoms as early as minutes after spending time outdoors, according to the Mayo Clinic.

“It’s very prevalent in the first month of summer,” said Dr. Rita Linkner, a board-certified dermatologist at Spring Street Dermatology. “As summer goes on and sun exposure increases, your skin hardens to that allergy and the rash diminishes.”

While an allergy to the sun sounds like a rare situation, polymorphous light eruption is actually relatively common, prevalent in up to 20 percent of people.

The exact cause is unknown, but doctors suspect some people may have a genetic predisposition to the condition.

Women, people with light-colored skin, and those with a family history of polymorphous light eruption have a higher risk of experiencing a rash from the sun.

Certain medications can also make your skin more sensitive to the sun, said Dr. Shari Lipner, a board-certified dermatologist at NewYork-Presbyterian Hospital.

“One of the most common reasons for a sun allergy to occur is due to medication, most commonly antibiotics like tetracyclines, doxycycline, and minocycline,” she said.

“These are common ones that we use to treat acne, so any young person getting an antibiotic for acne should ask their dermatologist how to protect themselves from the sun.”

While sun exposure causes both sun allergies and sunburn, there are some key differences in the conditions.

The main distinguishing factor is that sun allergy is an immunological reaction, wherein the body sees the sun-altered skin as a potential threat and kicks into defense mode to fight it, resulting in a rash.

Sunburn, on the other hand, is a burn from the radiation of UV light, resulting in reddish skin.

Experiencing a sun allergy doesn’t necessarily mean your skin has UV damage, but regular exposure to the sun without protection could lead to long-term health issues.

“Usually we see damage from UV rays from chronic sun exposure. Getting a reaction from a sun allergy once or twice, or getting a sunburn once, typically does not cause severe skin aging or skin cancers,” said Lipner.

If you experience a reaction from the sun, a dermatologist can diagnose what’s causing it.

“A dermatologist can examine the skin and determine if it’s a sun allergy or sunburn,” said Lipner. “We will mainly [ask about] the patient’s medical history, how fast the [rash] happened, how it feels, and the symptoms to make a diagnosis. If there’s any doubt, we can perform a skin biopsy to determine the cause.”

You spent the day lounging by the pool, and now you have an itchy red rash on your chest. Now what?

Generally, rashes from a sun allergy go away on their own within 10 days. You can try an over-the-counter anti-itch cream with hydrocortisone or an oral antihistamine to relieve some of the discomfort of the rash.

“If people have severe sun allergies, a board-certified dermatologist can put them into booths that emit UV light and work to harden their skin to sun exposure earlier in the summer, so they’re not having a prolonged response,” said Linkner.

While treatments for a sun allergy are straightforward, your best bet is to prevent a reaction to begin with. Here are some tips:

  • Limit the time you spend outdoors between 10 a.m. to 2 p.m., when the sun’s rays are the strongest.
  • Cover your skin as much as possible — long sleeves and a broad-brimmed hat can help reduce exposure.
  • Use a broad-spectrum sunscreen with an SPF of at least 30, said Lipner, and be sure to reapply frequently if you’re sweating or swimming.