TORONTO -- As the novel coronavirus continues to spread across the world, doctors have identified a new possible symptom of infection: skin lesions.

Dubbed "COVID toes" by the dermatology community, the lesions can typically appear on the feet but have also been seen on the fingers.

Dr. Ebbing Lautenbach, chief of infectious disease at the University of Pennsylvania's School of Medicine, says the lesions appear as blueish-red or purple bumps that hurt or feel warm when touched. He said they often occur on the pads of the toes, but can also appear on the upper side of the foot.

"They are often painful when you touch them and some people also describe feeling hot or burning," Lautenbach said in a telephone interview with "They've been demonstrated to be an early sort of physical manifestation of COVID, at least in some patients."

Lautenbach added that the lesions may not be a symptom for those over a certain age.

"It tends to be sort of the younger age groups that seem to be presenting with these more commonly so kids or young adults seem to have these more often than older people," he said.

Lautenbach said the lesions look similar to pernio or what is commonly referred to as frostbite, but they don't appear to have any relation to the weather.

"Anything that can cause a sort of a lesion on your toe is usually traumatic. What this actually looks the most like is the similar looking lesions in the toes that are typically due to exposure to cold temperatures,” Lautenbach said. “Given how the weather is in this time of year that is less likely to be the cause of these.

"But because there are other things that can cause these sort of appearing lesions, it doesn't absolutely mean that you have a COVID infection."

Lautenbach said what is most interesting about "COVID toes" is that the lesions predominantly appear in COVID-19 patients who don't exhibit any other symptoms.

Similarly, the sudden loss smell and/or the sense of taste has been found to be a potential sign of COVID-19 infection in cases of otherwise asymptomatic patients.

The World Health Organization (WHO) does not list the loss of smell, taste or skin problems as known symptoms of COVID-19, but has been watching closely as experts in several countries study the issue.

"We recognize that there are a proportion of people out there who have COVID infections who, for all intents and purposes, are generally asymptomatic. In some patients, [these lesions] may be the only clinical manifestation that they have of a COVID infection," Lautenbach said.

Dermatologists and doctors around the world are starting to see an increase of people with these lesions, leading them to believe it may be connected to COVID-19.

However, Lautenbach said the cases are varied and some patients have developed other symptoms of coronavirus in addition to the lesions.

Initial reports about skin problems associated with COVID-19 were first documented in late March by a doctor in Italy who found that 18 of the 88 patients studied (20 per cent) had some kind of skin problem.

However, the author of the report noted that the study was too small to make any generalizations about coronavirus and skin conditions.

"This is a relatively new component of what the clinical presentation of COVID might look like but when something like this is first described, it makes clinicians and patients more likely to look for it as part of a constellation of symptoms," Lautenbach said.

In response, the American Academy of Dermatology has asked its members and other physicians around the world to report any dermatological symptoms associated with COVID-19 to a registry so doctors can better understand how COVID-19 affects the skin.

A podiatrists' association in Spain has also opened a registry to track skin conditions that may be related to the virus. France's National Union of Dermatologists has also issued a notice to its members that the lesions can be a possible sign of infection.

While this evidence is not yet backed by peer-reviewed studies, Lautenbach suggested that anyone who is experiencing "COVID toes" should self-isolate.

"For people who have these lesions, even without pulmonary symptoms, it is probably a reasonable idea to self-isolate," he said.

In addition to cases in Europe, Lautenbach said there have been cases of the lesions "described all over the U.S."

Infectious disease expert Dr. Isaac Bogoch told via email that he has not yet seen any Canadian patients with COVID-19 suffering from "COVID toes," but said the lesions are being "increasingly recognized" among doctors as a symptom of infection.