A possible sign of COVID-19 could be in your socks.

Medical professionals created a registry to document skin conditions among coronavirus patients. About half of them have what's been dubbed "COVID toes."

The condition involves purple coloring and inflammation of the skin that looks similar to frostbite.

"We have had some very sick patients who have developed this, but they tended to develop this at the same time as their other symptoms,” said Dr. Esther Freeman, Director of Global Health Dermatology at Massachusetts General Hospital. “So, I don't want people to panic that if they see these toes that that means that something really bad is coming."

Dr. Freeman says the reaction could have other triggers, like spending time outside when it's cold or lupus. If you can't think of any other reason your toes are turning purple, you should call your doctor.

Some patients have shown no other symptoms and tested positive for COVID-19.

"That to me, I think is particularly concerning, because that's the group of patients that might not realize that they're putting their family members at risk," said Dr. Freeman.

Dr. Freeman says there are three other main skin conditions among coronavirus patients: measles-like rash, hives and a net-like pattern on the legs. Those are also common among other viruses.

However, the purple toes appear unique to COVID-19. Dr. Freeman says mostly young adults and kids have seen this.

It's important to note that right now, doctors still don't know “officially” if the virus is causing “COVID toes.”

Northwestern University shared some photos of people with the so-called “COVID toes.”

Dr. Amy Paller, a dermatologist with Northwestern Medicine, is part of a national pediatric dermatology registry collecting images across the U.S. She said more testing is needed to definitely know what is causing the condition.

“We don’t know for sure if it’s related to COVID-19, but when it’s so common right now during a pandemic and is occurring in otherwise asymptomatic or mildly affected patients, it seems too much of a coincidence not to be a manifestation of the virus for patients in their teens and 20s,” said Paller, the chair of dermatology at Northwestern University Feinberg School of Medicine and a pediatric dermatologist at Ann & Robert H. Lurie Children’s Hospital of Chicago.

Dr. Paller says she’s seen photos of about 30 cases of the condition.

“I think it’s much more rampant than we even realize,” said Dr. Paller. “The good news is it resolves spontaneously.”

Given the shortage in testing for the virus right now, Dr. Paller recommends getting antibody testing when available to confirm the association in these otherwise largely healthy kids.

