This common summer ailment can leave you howling in pain

A hangover might be the least of your worries after that poolside cocktail.

As summer heats up, doctors are warning about so-called “margarita burn,” a blistering rash that can leave you wincing in pain long after the last sip.

“It’s more common than you think,” Dr. David Kim, a board-certified dermatologist, said during a recent segment on TODAY. 

What is a margarita burn?

Officially called phytophotodermatitis, it’s a painful skin reaction that occurs when certain plant-based chemicals called furocoumarins come into contact with the skin and are then exposed to ultraviolet A (UVA) rays from the sun.

Furocoumarins are found in citrus fruits like limes and lemons, as well as in other plants such as celery, parsley, figs and carrots.

“I commonly see phytophotodermatitis when somebody has been barbecuing on a sunny afternoon and having drinks with limes in them, like margaritas or beers,” Dr. Melissa Piliang, a dermatologist, said in an interview with the Cleveland Clinic.

What does a margarita burn look like?

At first glance, it can pass for a nasty sunburn.

The reaction usually begins within 24 to 48 hours of sun exposure and can cause redness, swelling, painful blisters, burning and intense itching. In more severe cases, large, fluid-filled blisters can form, making the skin feel raw and irritated.

“It only develops in areas where the chemical touches the skin, explaining odd shapes like streaks or dots where lime juice may have dripped down the skin or splashed,” Dr. Joshua Zeichner, director of cosmetic and clinical research at Mount Sinai Hospital, told Prevention. 

The severity depends on how much sun and plant chemical exposure you’ve had.

While the rash itself may clear in a few days, phytophotodermatitis often leaves behind dark spots or patches of discoloration known as hyperpigmentation — and those can stick around for weeks, months or even years.

Who’s at risk for margarita burn?

Anyone mixing furocoumarins and sunlight can develop margarita burn, but some groups are more vulnerable.

For example, fair-skinned people and those sensitive to the sun are at higher risk, according to the Cleveland Clinic.

Chefs, bartenders and food service workers who handle citrus outdoors — especially on patios, at pool bars and beachside venues — are also more likely to be affected.

But it’s not just about cocktails. Hikers, bikers and gardeners can unknowingly brush up against wild plants packed with furocoumarins, making them prime targets, too.

How do you treat a margarita burn?

“If you get a rash, you can use steroid creams to calm down the inflammation, and you can use brightening serums with kojic acid and arbutin to prevent hyperpigmentation,” Kim said. 

Applying a cool washcloth can soothe the skin, while over-the-counter pain relievers like aspirin or ibuprofen and topical corticosteroids can ease discomfort.

“While most mild cases of phytophotodermatitis clear up on their own with over-the-counter creams, it’s critical to see your doctor if you don’t see an improvement after several days,” Dr. Melanie Palm, a dermatologist, told Verwell Health. 

A doctor can prescribe stronger medications and confirm the diagnosis, since the rash can resemble other conditions such as fungal infections, sunburn or poison ivy.

How can you prevent a margarita burn?

The good news: avoiding the painful reaction is easier than you might think.

If you’ve handled furocoumarins, like when juicing limes, wash your hands thoroughly with soap and water right after, Dr. Samer Jaber, a dermatologist, told CBS News.

Be vigilant about sun exposure: use a high-UVA-protection sunscreen and stay in the shade when possible.

For gardeners, cooks and bartenders working outdoors, wearing gloves can also add an important layer of defense against the chemicals that cause margarita burn.