A new study has found evidence supporting a link between "COVID toes" -- bluish-red or purple lesions that can appear on the feet and hands of children and young adults -- and the novel coronavirus.

The study, published Wednesday in the British Journal of Dermatology, reported that the SARS-CoV-2 virus that causes COVID-19 was present in skin biopsies in children with symptoms of "COVID toes," despite negative results from traditional testing methods.

"Our findings support a causal relation of SARS-CoV-2 with COVID toes. Endothelial damage induced by the virus could be the key mechanism causing these lesions," lead author Dr. Isabel Colmenero of Spain's Hospital Infantil Universitario Nino Jesus said in a press release.

The study looked at different skin changes in 375 patients with COVID‐19 infections. In the majority of cases, the affected individual tested negative with traditional COVID-19 tests involving throat swabs and antibody measurements.

However, when tested by skin biopsies, most patients tested positive for the novel coronavirus. The patients reported few or no other symptoms other than the skin lesions.

Researchers reported that the virus was detected in sweat glands and virus particles were found attached to the walls of the skin's blood vessels. An electron microscopy in one biopsy also found viral particles within the skin's endothelial cells

According to the study, the skin lesions may be caused by small blood clots forming in veins not normally affected by critical illnesses.

"Furthermore, vascular damage could also explain some clinical features seen in patients with severe COVID-19," Colmenero said.

Dr. Ebbing Lautenbach, chief of infectious disease at the University of Pennsylvania's School of Medicine, previously told CTVNews.ca that the lesions look similar to pernio or what is commonly referred to as frostbite, despite not having any relation to weather. He said the lesions can also hurt or feel warm when touched.

"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 in a phone interview.

"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," he added.

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.

The Canadian Paediatric Surveillance Program (CPSP) issued a public health alert in April warning doctors and parents about skin changes on children's feet or hands as a possible sign of COVID-19 infection.

Dermatology associations in the United States, France and Spain have issued similar alerts while the World Health Organization added skin rashes and discolouration to its list of known symptoms of COVID-19 in May.

Researchers of the latest study caution that there are still a lot of unknowns when it comes to SARS-CoV-2 and the virus may lead to other dermatological changes in addition to "COVID toes."

Pediatric emergency physician Dr. Dina Kulik previously told CTV News Channel that parents should call their family doctor if they notice any skin problems in themselves or their children.

"If your child is unwell, of course you want to seek medical care, if your child is very unwell you'll want to go to the emergency room," Kulik said.

"But if, just a rash and no other symptoms, it's best to touch base with your physician and stay home, stay isolated, and make sure you're not seeing anyone that's at risk of serious infection like the elderly and people with chronic health conditions."