Have you seen the Corona TV ad in which a woman, irritated that her beach companion has been staring at a bikini-clad blonde, squirts him with the lime sitting atop his beer?
Well, according to a dermatology journal, he may have been in for worse than a surprise: a nasty skin reaction that one doctor is calling "Mexican beer dermatitis."
Dr. Scott Flugman, of Huntington Hospital in New York, reports in the Archives of Dermatology that a substance in lime juice, if left on the skin in the sun, can cause the skin to become discolored, as if stung by jellyfish or poison ivy. And the marks can last for months.
Here's how it happens: Mexican beers, particularly Corona, are typically served with a lime slice wedged into the top of the bottle. The drinker then shoves the lime into the bottle and holds his or her thumb over the bottle's mouth while turning the bottle over to mix in the juice.
If the drinker isn't careful, however, the beer's carbonation can spray lime juice and beer all over his or her skin -- "especially in a patient who is shirtless by a beach or pool," the journal notes.
The ensuing reaction -- most commonly seen in people such as bartenders who work outdoors with limes -- owes to a substance called psoralen, Flugman told Reuters Health.
Psoralen is used to make the skin more sensitive to the effects of a wavelength of ultraviolet light known as UV-A, which is used to treat certain skin conditions.
When it's lime juice on your skin, however, it's a different story. (Lemons contain psoralens, too, although weaker ones).
Most cases aren't severe and won't leave a scar. "It's just a cosmetic issue," said Flugman. But he added that the skin reaction may take an emotional toll.
"People are worried it's something serious. You might have some brown spots you're looking at for a few months," particularly in olive-skinned Caucasians.
The link between sunburns and skin cancer may also worry people, but no one has shown any specific tie between this kind of dermatitis and cancer, Flugman said.
At his two-dermatologist practice in Long Island, New York, he sees two or three cases per year -- other cases probably go away before people get to a dermatologist.
It's not clear just how common the problem is, and Flugman's write-up is just a case report, the lowest level of medical evidence. Yet most dermatologists know the skin reaction exists, "even if they haven't seen it recently," Flugman told Reuters Health.
Making more people aware of it, he said, will reassure them that the reaction will probably go away, or let them avoid it in the first place.
"The people I see sometimes are kind of panicked," he said. They are often mystified why a dermatologist is asking them if they've recently drunk Mexican beer.
Crown Imports, which distributes Corona in the U.S., could not provide a comment by deadline.
Flugman's advice? "If you do this and you spritz the beer or the lime, just wash it off. Don't leave it on there and sit out in the sun."
Or, if you aren't inclined to get up for while, "throw a towel over it."