What Are Sun Allergies? Plus, Signs You May Be Experiencing Them

There's more than one type of reaction you can have.

We’ve all spent a bit more than our fair share in the sun and walked away with a nasty sunburn. Call it youthful ignorance or the fact that, oops, you forgot to reapply your sunscreen (always reapply your sunscreen, folks), but what if there’s something more going on. Could what you experienced be a sun allergy, and if it is, what exactly do you do about it? 

What is a sun allergy? 

At its most basic, dermatologist Hadley King, M.D defines a sun allergy as when the body’s immune system reacts to sunlight. Your immune system senses the sun-affected skin and flags it as foreign cells. There are several types of sun allergies:

The most common type of allergic reaction is called polymorphous light eruption or PMLE. Typically, this reaction happens on the first days of sunny seasons when the skin is initially exposed to sunlight. Dermatologist Joshua Zeichner, M.D. explains to HelloGiggles that over time, with increased exposure, the skin will go through a process known as “hardening” when the exposed areas will adjust to the sunlight and no longer react.

Other types of sun allergyies according to Dr. King, are also photosensitivty reactions which fall into two categories: phototoxic and photoallergic. The first you’re likely already familiar with phototoxic reactions—they happen when a topically applied product has an ingredient that reacts with the UV rays from the sun. These happen a few minutes or hours after exposure. Photoallergic reactions, however, are similar but less common and instead trigger the immune system resulting in blisters, red bumps, or lesions days after sun exposure. 

Lastly, there’s phytophotodermatitis, which Dr. Zeichner says is mainly caused by plants or essential oil usage. You may have heard of this reaction referred to as “margarita rash,” as it’s a common occurrence when lime juice is on the skin and then exposed to the sun.

sun allergy

How can I tell if I have a sun allergy?

When it comes to watching out for sun allergies, it’s first important to note that PMLE is not very common. In fact, Dr. King says it only affects about 10-15% of the population. However, if you are concerned, she says the reaction often shows itself in “itchy or burning red bumps or blisters or patches on sun-exposed areas of the skin.” While reactions in deeper complexions are likely to take on more flesh-colored bumps with melanin disguising underlying redness, the skin will still experience the other topical signs even if they aren’t a red-hue, according to Dr. Zeichner.

What’s more likely than PMLE, though, is for you to have a photosensitive reaction due to topical treatments or medications you might be using. Phototoxic reactions—the more common of the two photosensitive varieties—will “look and feel like a sunburn or a rash” according to Dr. King, and she says photoallergic reactions could feature more severe signs like “rash, blisters, red bumps or oozing lesions one to three days after sun exposure.”

How can I treat a sun allergy? 

If you believe you’re having minor sun allergies, you can treat it at home. Dr. King says an oral antihistamine can help relieve symptoms from the reactions. As for Dr. Zeichner, he recommends using a topical anti-inflammatory cream, like an over-the-counter 1% hydrocortisone. However, he cautions that the cream shouldn’t be used for more than two weeks in a row—if it hasn’t helped within that time frame, consult your dermatologist about treatment. 

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What’s the best way to prevent sun allergies?

This one might seem a bit obvious, but both Dr. King and Dr. Zeichner say the best way to avoid sun allergies is to avoid the sun. If you must be in the sun, it’s best to wear protective clothing, try to find shade, and avoid being outside during peak hours, which Dr. King cites as 10 A.M. to 4 P.M. Be sure to check any medications or topical treatments and products you’re using in case they cause photosensitivity, too. 

Of course, there’s always sunscreen. Dr. King says to get an SPF that is 30 or higher that’s marked as “broad-spectrum,” as those will block both UVA and UVB rays which contribute to sun allergies. Furthermore, she suggests mineral formulations as they are “sometimes better because they block more wavelengths.” Regardless, wearing a sunscreen is a must.