Not long ago, my sister returned from a wedding in Mexico with a sun-kissed tan, the very envy of everyone living in Manhattan during the hybrid months of winter-spring. She had nary a hint of sunburn, either—what she had was much worse: a dark brown, rashlike burn on her hip. My first thought was melanoma, and I couldn’t help but worry that she’d call me from the dermatologist with that very diagnosis. Alas, she texted me after her appointment: “Not cancer! I have margarita dermatitis.”
Scientifically known as phytophotodermatitis, "margarita dermatitis" occurs when sun-sensitizing ingredients called psoralens are on the skin prior to sun exposure, explains Katie Rodan, M.D., a cosmetic dermatologist and co-creator of Proactiv. Psoralens are natural compounds found in lime (hence the margarita nickname), celery, parsley, and other acidic fruits and vegetables.
“The reaction is phototoxic, creating a brown, purplish discoloration that is very alarming to people. It’s not uncommon to get a blister from it, either,” says Meghan O’Brien, M.D., a dermatologist at Tribeca Park Dermatology in New York City. “Most people come in and think they have melanoma, so being aware of it can alleviate that fear.”
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While you can treat phytophotodermatitis with a steroid if it's identified in the first 24 to 48 hours, most often you just need to allow it to fade naturally, which can take between a few weeks and a few months, Dr. Rodan says. Luckily it's safe to use makeup to cover up the discoloration if it happens on your face.
In addition to be mindful of your drinks in the sun, read labels carefully before applying anything prior to heading outside because lotion, bergamot (a citrusy fragrance found in many perfumes), and oils with citrus in them can also trigger the reaction. And if you get a little messy with your Corona and come in contact with one of the agents, Dr. O’Brien advises to wash the affected area thoroughly and then apply a UVA-based sunscreen since UVA rays spur the reaction.