Generally speaking, a sun allergy rash (as opposed to just a sunburn) will appear after UV exposure, so it’s fairly easy to spot photosensitivity. Still, if you never knew that a sun allergy was a thing, it helps to understand the key characteristics of sun sickness. To give you the full rundown, we chatted with two board-certified dermatologists for everything there is to know about the subject. Keep reading to learn more.
How do you know if you are allergic to the sun?
If you develop a rash in conjunction with sun exposure, there’s a chance that you have a sun allergy. Most often, this allergy falls within one of two categories.
“The most common [sun allergy rash] is polymorphic light eruption (PMLE) which typically happens to people in their 20 to 30s,” says board-certified dermatologist David Kim, MD. “It usually occurs in the spring or early summer upon first sun exposure of the season and people develop itchy red bumps on the arm, chest, back, and legs 24 to 48 hours after sun exposure.” What’s particularly interesting about PMLE is that, while it affects the body, it usually spares the face, Kim adds.
That’s not to say that younger people can’t develop a sun allergy, though. According to Dr. Kim, there’s a variation of PMLE, called Juvenile Spring Eruption, which occurs in children between the ages of five to 12. The biggest difference between classic PMLE and Juvenile Spring Eruption is that the sun allergy can manifest in the form of a facial rash. “The itchy rash usually develops on the ears, cheeks, lips, and hands, 24 to 48 hours after sun exposure,” Dr. Kim says, noting that it typically improves and resolves with age.
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Meanwhile, if you develop a rash within seconds or minutes of being out in the sun, Dr. Kim says that Solar Urticaria is likely at play. “Solar Urticaria is a relatively rare rash people can develop due to UV rays,” he says. “These are essentially itchy hives that are transient and disappear within one to two hours.”
What does a sun allergy look like?
A sun allergy rash looks a lot like other allergic reactions, as it presents in the form of itchy red bumps (ie: hives) on all sun-exposed areas, Dr. Kim says. “In severe cases, the bumps can progress to vesicles (small fluid-filled bumps) to blisters. But they’re mostly itchy red bumps that resolve over time (one to two weeks) without scarring or blistering.”
What’s the best way to prevent a sun rash?
If the idea of developing a sunburn rash or sun poisoning blisters is enough to make you want to stay out of the sun altogether, know that other, less extreme measures exist. According to Dr. Kim, the best way to avoid a sun allergy rash is to avoid the sun during peak hours (10 a.m. to 2 p.m.), to wear sunscreen with SPF 30 or higher on your face and body, to reapply your SPF every two hours, and to wear sun-protective clothing.
On the topic of sun-protective clothing, board-certified dermatologist Dustin Portela, MD says to look for garments that are UPF rated. “These physically block the sun from reaching your skin,” he explains. Need some recos? The Lululemon Waterside Half-Zip UV Protection Paddle Top ($88), Lilly Pulitzer UPF 50+ Leona Zip-Up Jacket ($108), and the Athleta Transcend ⅞ Tight ($55), all offer UPF protection.
How do you treat a sun allergy?
Unlike nut allergies or bee allergies, sun allergies typically resolve on their own without hinting toward symptoms of anaphylactic shock. What’s more, the more you experience sun rashes, the more tolerant your skin will become to UV rays, says Dr. Kim.
Still, if the rash is super itchy, he says that using a gentle moisturizer with a gentle steroid can work as a sun allergy treatment to offer instant relief. “This will relieve the itch and minimize the scratching, which will then minimize the risk for hyperpigmentation,” he says.
If you find yourself reaching for Benadryl ($9) for a sun allergy, Dr. Kim notes it can help with the feelings associated with a sun reaction, but not the visible symptoms. “Antihistamines will help with the itching but they won’t necessarily make the bumps go away quicker,” he explains.
Another downside of using Benadryl to treat a sun allergy rash is that it could make you feel drowsy during your summer activities. “You can alternatively take an antihistamine like Zyrtec ($23), Claritin ($27), or Allegra ($30), which are less likely to cause drowsiness,” says Dr. Portela. “Over-the-counter hydrocortisone can also help if you limit use to only a few days.”
That said, if your sun allergy rash doesn’t dissipate within a few days, Portela says to make an appointment with your dermatologist to determine what’s causing your skin to react in such a way.
Can I suddenly be allergic to the sun?
Most often, sun allergies present themself early in life, says Dr. Kim. So, if you have never developed a rash after spending time in the sun, then all of a sudden do, he notes that it’s likely not a sun allergy but rather a sign of photoallergic or phototoxic drug reactions. “This is when the medications you take or apply (on the skin) interact with UV rays and cause an allergic reaction,” he says. “So it’s not your skin reacting, it’s the medication that’s reacting to UV rays.”
Luckily, it’s typically pretty easy to spot the difference between a sun allergy and a photosensitive reaction. “If it’s a sun allergy, you’ll develop the rash in ‘photo-distributed’ patterns, AKA all areas that are exposed to the sun (not just the face),” Kim says, noting that the rash usually sets in hours after exposure. “If it’s an allergic reaction to your sunscreen, you’ll experience tingling and burning almost immediately and you’ll develop dermatitis (inflammation of the skin) only on the areas you applied sunscreen [or another photosensitive skincare ingredient].”
With this in mind, it’s worth knowing which skincare ingredients can potentially cause adverse reactions when applied directly before sun exposure. As a rule of thumb, it’s best to avoid retinol, salicylic acid, fruit enzymes, and AHAs directly before sun exposure. While these ingredients can undoubtedly boost any skincare routine, they can make your complexion more susceptible to burning and discomfort when in contact with UV rays.
The Takeaway
Sun allergies exist—who would’ve thought? The good news is that sun allergies aren’t dire, so they don’t require avoiding sunlight altogether. Instead, stock your closet with UPF-protective clothing, make sunscreen a mainstay in your face and body skincare routines to avoid sun damage and to lower your risk of skin cancer, avoid peak sunlight hours, and evaluate your daily skincare regimen before heading out for a day in the sun. And on that note, know that you don’t have to nix ingredients from your routine altogether. Instead, use them at night time if you know you’ll be spending the next day in the sun. If you absolutely can’t bear the thought of foregoing your favorite products, though, your other option is to religiously apply SPF of at least 30 or higher. For full protection, squeeze a line of sunscreen on your fore and middle fingers—that’s how much sunscreen you need to ward off the sun’s harmful UV rays from your face, and that amount must be applied every two hours to maintain the protection and reduce your risk of developing photosensitivity.
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