A new study suggests that covid toes are caused by an immune system response.

Doctors were perplexed by a rush of patients, primarily teens and young adults, who came in complaining of chilblains — painful sores on their toes and occasionally on their fingers, shortly after the epidemic broke out last year.

A new study suggests that covid toes are caused by an immune system response.

Covid toes was the name given to the ailment. Even though majority of the patients tested negative for coronavirus, they were viewed as yet another unusual telltale indication of the disease, alongside the loss of smell and taste. Physicians were stumped when it came to explaining the link.

White individuals have red or purple lesions, whereas people of color have purplish or brownish lesions. They create unpleasant burning or itching sensations, making it difficult for patients to walk or wear shoes.

Now, a recent French research published in the British Journal of Dermatology offers some insight on the origins of Covid toes. According to the findings, the lesions might be a result of the immune system going into overdrive in reaction to the virus, causing harm to cells and tissues in the process.

Blood samples and skin biopsies from 50 individuals who developed chilblainlike lesions for the first time in April 2020 and were referred to St.-Louis Hospital in Paris were studied by the French researchers.

Other symptoms indicative with Covid-19, including as coughing, shortness of breath, and loss of smell, were present in slightly more than half of the patients, but all of them tested negative for the virus on PCR testing.  Type 1 interferon, a protein that activates the body's immune system to combat infections but may potentially inflict harm, was found in significant concentrations in the samples. The researchers also discovered high amounts of an antibody that might target the body's own cells unintentionally.

The study shows that abnormal alterations in the linings of blood vessels may potentially play a role in the lesions. 

The authors noted that while the link between coronavirus infection and chilblainlike lesions "remains contentious," "peaks of chilblainlike lesions contemporaneous with peaks of Covid-19 fatalities in 2020 clearly imply that this condition is closely connected to SARS-CoV-2 infection."    

The origin of Covid toes is not surprising; one of the disease's characteristic symptoms is an immune system overreaction known as a cytokine storm, which may end up causing more sickness than the virus itself.

source: https://onlinelibrary.wiley.com/doi/10.1111/bjd.20707