• “COVID toes” – purple, swollen toes that look as if they’ve been frostbitten – may be the latest indication of a coronavirus infection.
  • The American Academy of Dermatology has received over 200 submissions of dermatological manifestations that healthcare providers are seeing in patients with COVID-19, and about half have noted these lesions.
  • “My message to the public would be: If you develop these, talk to your healthcare provider,” said Dr. Esther Freeman, a dermatologist and epidemiologist at Massachusetts General Hospital who’s managing the registry.
  • “In the absence of another reason to have these ‘COVID toes,’ you may want to consider testing,” she added.
  • Read live updates about the coronavirus here.

Purple, swollen toes that look as if they’ve been frostbitten may be the latest indication of a coronavirus infection, doctors say.

Dubbed “COVID toes” by the dermatology community, this symptom could indicate that you should get tested for COVID-19, the illness caused by the coronavirus. Others have included anosmia, or a loss of smell, and conjunctivitis, also known as pink eye, which the American Academy of Ophthalmology recently suggested could be a sign of a coronavirus infection.

The American Academy of Dermatology launched a registry last week to track the dermatological effects that COVID-19 patients may be experiencing and had received over 200 submissions from healthcare providers as of Wednesday afternoon.

Dr. Esther Freeman, a dermatologist and epidemiologist at Massachusetts General Hospital and a faculty member at Harvard's medical school, is managing the registry in collaboration with the AAD. So far, Freeman told Business Insider, about half of the cases in the registry noted these lesions in the hands or feet that resemble frostbite.

Never miss out on healthcare news. Subscribe to Dispensed, Business Insider's weekly newsletter on pharma, biotech, and healthcare.

She said she'd also seen several of these cases in her own patients in recent weeks; she said she connected with patients through virtual consultations.

"My message to the public would be: If you develop these, talk to your healthcare provider," Freeman said. A doctor would ask questions about whether there may be any other reasons you would be developing these lesions.

"In the absence of another reason to have these 'COVID toes,' you may want to consider testing and think about potentially limiting the risk of spread to other people," she said.

coronavirus

Foto: Medical workers preparing to test for the coronavirus. Source: Getty

What causes COVID toes?

A lot is unknown about what's causing this condition, Freeman said. She said there were a few main theories circling in the medical community.

One is that the lesions may be showing up because the virus causes general inflammation in the body. Another is that the virus may be causing vasculitis, meaning the walls of the blood vessels themselves are becoming inflamed. A third possibility is that the lesions may be caused by blood clots in vessels in the skin - doctors are increasingly seeing blood clots as a complication of the illness.

But it may end up that more than one of these hypotheses is true, Freeman said. It could be a combination of these things, or some patients may experience COVID toes for one reason while others experience them for another.

"It's possible that it's a spectrum," she said.

Interest from the medical community on Twitter

A recent tweet about COVID toes from Dr. Ilan Schwartz, an infectious-disease specialist in Edmonton, Alberta, garnered over 2,300 retweets and 3,500 likes.

Schwartz told Business Insider that though he hadn't seen COVID-19 patients with swollen toes in his own practice, he had seen immense interest in the topic from the medical community. He said several people left comments on his post and sent him private messages relaying their experiences with the symptoms.

In a recent webinar where Schwartz was presenting on the virus to family doctors in Calgary, an audience member also raised the question of whether he or others had seen lesions in the toes of COVID-19 patients, he said.

Schwartz said that though it's still early and the cases are mostly anecdotal, he felt quite certain that the frostbite-like toes in some COVID-19 patients were a sign of the disease.

"But it's going to take a very large population that is surveyed to be able to make any definitive findings, and that might still take a while," he said.

Patients with COVID toes tend to be younger and may not have other symptoms

Most COVID-19 patients experiencing painful and swollen toes seem to be younger, said Dr. Lindy Fox, a professor of dermatology at the University of California at San Francisco who is also involved in the AAD's registry. Many of them also appear to be relatively healthy and show few or no other symptoms.

Fox suggested that anyone experiencing these symptoms get both a diagnostic test to see whether they're currently infected and an antibody test to show if they were infected previously.

However, she noted that the inflamed, purple toes themselves aren't necessarily indicative of someone developing other serious symptoms of COVID-19.

The toe problems can show up during other symptoms or after they've subsided, Fox said.

COVID toes may reveal the scope of exposure to the coronavirus

These frostbite-like symptoms can happen for reasons unrelated to the coronavirus, especially during the winter or in areas with cold climates.

But the number of cases of these toe problems, called pernio, that the medical community has seen - especially in countries like Spain and Italy that have warmer climates - has prompted doctors to consider that the cases might be related to the virus.

Fox said that "it is an astonishing number" of patients who have these symptoms.

She said that the lack of testing for the virus means we don't really know how many people have had it and that the toe problems were another indication that the virus is widespread.

"We're understanding that many more people than we ever thought were exposed to the virus, had it, because our testing has been so poor," Fox said.