Spanish researchers for the first time demonstrated the presence of the novel coronavirus in human skin after examining samples from pediatric patients with so-called "COVID toes."
Scientists at the Nino Jesus Hospital in Madrid published their findings in the peer-reviewed British Journal of Dermatology this week.
Beginning during the chaotic peak of the pandemic in Spain at the end of April, the study observed that in just one week, more than 30 children with skin lesions were rushed to the hospital's emergency room.
The lesions appeared to be chilblains -- painfully inflamed small blood vessels mostly occurring on toes, but also fingers.
Normally, chilblains emerge as a reaction to cold or damp conditions in the winter. However, the condition became increasingly prevalent -- primarily in children and young adults -- as the virus spread around the world.
As the deluge of swollen toes began, doctors suspected they were related to COVID-19, but were unsure how or why. Quickly, the swollen red or purple appendages became known as "COVID toes."
By confirming the virus's presence in the skin biopsies of seven patients, researchers say they can now "confirm these lesions are part of the spectrum of COVID-19."
Without evidence, some doctors had previously hypothesized that COVID-toes were a side-effect from staying home during lockdowns and walking around barefoot.
A direct link was also uncertain because, according to the paper, most patients with the condition tested negative for the virus in PCR (Polymerase chain reaction) tests, considered the gold standard of detection.
In this study, all seven patients, aged 11-17, whose skin was analyzed, tested negative for COVID-19 in a PCR test.
The researchers later detected viral particles within the inner layer of the blood vessels found in their skin samples.
The research also suggests that COVID-19 caused these lesions by damaging the circulatory system, something also seen in patients with thrombosis, or blood clots.
"Our findings support the hypothesis that widespread endothelial infection by SARS-CoV-2 could have a role in the pathogenesis of severe forms of the disease," says the report.
All of the patients in the study saw their lesions spontaneously heal without any significant complications after two months.
