Having a bunch of fish nibble off your dead skin is usually just a vacation novelty, but it may have caused one woman's toenails to fall off.
Fish pedicures involve dipping your feet in a warm tub full of Garra rufa fish, also known as "doctor fish." The little guys usually eat plankton in their natural habitat, but if there are none around, they're happy to nibble on dead skin instead. Delicious!
There's real evidence that these fish really do remove some dead skin, and they're a popular tourist activity in the Mediterranean. But there were already a lot of questions around the safety of fish pedicures in addition to the missing toenails.
A case reported in the journal JAMA Dermatology tied a woman's six-month history of toenail issues to a fish pedicure. According to Dr. Shari Lipner — who wrote the report — the patient was diagnosed with onychomadesis. This is the technical term for when nail growth temporarily stops, which leaves a gap in the nail and makes the nail fall off.
The woman, according to Lipner, hadn't experienced any sort of trauma that would explain the condition. The only thing out of the ordinary that had happened was the fish pedicure. Although Lipner wasn't able to pinpoint exactly how one led to the other, she concluded, "It is likely that direct trauma caused by fish biting multiple nail units causes a cessation in nail plate production."
"To my knowledge, this is the first case of onychomadesis associated with a fish pedicure," wrote Lipner.
But another dermatologist is disputing Lipner's conclusion. Dr. Chris Adigun, a board-certified dermatologist and nail specialist in North Carolina, told BuzzFeed News that she thinks the woman had a different condition called retronychia.
Retronychia happens when a nail feels too much sustained pressure, disrupting nail-making. That leads to multiple layers of nail, giving a thicker appearance. Those layers can peel off.
"It's [a] condition that I see pretty frequently from women who wear tight-fitting shoes," Adigun said.
She added that she'd have to see the patient in person to be sure, but that a fish pedicure is unlikely to cause onychomadesis, which is usually triggered by an underlying illness or chemotherapy.
"I think for the most part fish pedicures are probably harmless," she said. "It can't get to the nail-making tissue because it's under the nail."
"I think it's undue cause of alarm," she added. "I think she was wearing the wrong shoes."
Whether the pedicure was responsible for the toenail situation or not, it's pretty clear that fish pedicures carry risks. They're banned in at least 10 states in the US, as well as in parts of Europe. Unlike traditional pedicure tools, which are sanitized or discarded after use, there's no way to stop the fish from spreading disease or bacteria from one person to another.
According to the piece by Lipner, there have been several cases of bacterial infection caused by fish pedicures, and studies have found some fish that are kept in spas carry bacteria.
Still, Adigun said that the average spa pedicure is probably more harmful, because snipping cuticles causes unnecessary damage. "When they cause those small wounds around your toenails, that's your highest risk for infection," she said.
"That is far more risky than having little fish eat keratin off your feet."