In the Chicago area, teens and young adults are developing red, purple, sore and itchy toes that doctors are informally calling “COVID toes.”

Dr. Amy Paller, the chair of dermatology at Northwestern University’s Feinberg School of Medicine, said that in the past week she’s gotten more than 50 reports of new pediatric cases in the Chicago area. She said she expects many more cases as news of the condition spreads.

“We don’t know for sure if it’s related to COVID-19,” she said. “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.”

While the condition can be painful and unpleasant, Paller said it is not life-threatening, and usually clears up on its own in three to four weeks.

“People usually present without any other symptoms,” she said, adding that patients can take pain relievers for the soreness.

That said, Paller urged patients to report the condition to their doctors and be tested for the COVID-19 antibodies or virus when possible.

That, however, may be more easily said than done. When I called in a case of COVID toes to my pediatrician this week, I was told to immediately schedule a COVID-19 virus test at Lurie Children’s Hospital. But a hospital staffer said they are not currently testing patients without additional COVID-19 symptoms, because testing supplies are still limited.

A Lurie’s spokesperson did not immediately respond to a request for comment.

Paller, who is also a pediatric dermatologist at Lurie Children’s Hospital, said she has heard similar stories from parents and understands the restrictions at this time.

“The problem is we are still resource-poor, and we have to save [virus testing] for people who are sick,” she said. .

Plus, the small group of COVID toes patients who have been tested for the virus have mostly come back negative, she said.

A teenage patient’s foot as pictured on April 6, 2020, three days after the onset of the skin condition being informally called COVID toes, marked by a dusky hue to the discoloration.

“We think people who have [COVID toes] are probably past the infectious phase, and in something called the convalescent phase,” she said. “So it is not something to worry about, except to follow up and take care of the symptoms.”

But even if most patients won’t benefit from COVID virus testing, Paller said antibody testing could be enormously helpful to research on the condition.

“I would recommend for absolutely everyone who has this to get antibody testing,” she said despite the still imperfect state of antibody testing. “I think when we start out with anything new there is going to be some unreliability. … Antibody testing is not 100%, even with the best techniques, and it relies on timing and mounting the immune response. So we want it to be a least three weeks out after symptoms before doing any antibody tests.”

While doctors believe COVID toes to be new, Paller noted it resembles a skin condition called pernio that is usually only seen in the coldest months.

“The condition we’re seeing can look just like pernio, but often varies from being bright red to purple, and not uncommonly affects broader areas of the toes,” Paller said. “Sometimes the bottom of the feet has circles of discoloration — and the fingers occasionally show similar discoloration. Sometimes the feet are itchy, sometimes painful, sometimes without any symptoms.”

The first cases were reported out of Italy and Spain, but Paller is on a team putting together a national directory of cases in the United States.

Paller said she is not sure why someone exposed to COVID-19 would develop toe symptoms, but suggested it could be an inflammatory response to the virus.

“We know this involves the small blood vessels in the hands and feet and is an inflammatory reaction,” she said. “Pernio, which this resembles but is a response to cold, involves clamping down of these small blood vessels — and we think something like this may be happening in response to the inflammation, perhaps caused as part of the response to the COVID-19 virus.”

Questions of why the condition is affecting young people, and what it indicates about the virus, remain unclear. But Paller hopes to learn more through increased testing.

“A minority of these patients with this have been tested for COVID-19 and many have been negative, but we still suspect a relationship. Many have had some mild viral symptoms in the week before,” Paller said. “It might be a sign during the ‘convalescent’ healing period when [a person is] no longer contagious. We won’t understand the association until we can test this more broadly.”

Monica Eng is a reporter for WBEZ. You can follow her @MonicaEng.