Doctors have identified a possible new symptom of coronavirus which sees purple or blue lesions appear on the feet of otherwise asymptomatic patients.
The symptom, which has been dubbed 'COVID toe', was discovered in March by Italian doctors and is now being more recognised in cases across the United States, USA Today reported.
Dr Ebbing Lautenbach, chief of infectious disease at the University of Pennsylvania's School of Medicine, says the lesions appear in toes and occasionally fingers and seem to be a sign someone has the virus.
"They're typically painful to touch and could have a hot burning sensation," he said.
ABC News reported the lesions to look similar to blotches of frostbite.
Dr Misha Rosenbach, associate professor of Dermatology at the Hospital of the University of Pennsylvania said they think they are linked to COVID-19 but aren't completely sure yet.
"What we are seeing tends to be in response to the cold, but we’re seeing it in the middle of spring.
"And it's happening in such numbers as is COVID that we have to think there’s a connection," she told ABC News.
Lautenbach says it is particularly interesting because they appear before any other signs of coronavirus and patients sometimes test negative because the virus is in such early stages.
"This is a manifestation that occurs early on in the disease, meaning you have this first, then you progress.
"Sometimes this might be your first clue that they have COVID when they don’t have any other symptoms."
In some cases, the lesions are the only symptom that ever develops.
The symptom is also believed to be more common in children and young adults which could be because those age groups have better immune systems, USA Today reported.
Lautenbach says there are two possible causes for them; there may be an inflammatory response more localised to COVID-19 patients' feet, or it could be the clotting of blood vessels.
"The short answer is nobody knows," he says.
COVID toes take between a week and 10 days to disappear and some patients go on to experience the harsher symptoms of COVID-19 including shortness of breath and fevers.
