The skin condition known as Covid toes can be a side effect of the immune system’s response to fighting the virus, a new study found.
The symptom results in chilblains-like inflammation and redness on the hands and feet, sometimes with the condition lasting for months.
It typically develops within a week to four weeks of infection and can cause toes and fingers to swell or change color.
Researchers behind the study, which was published in the British Journal of Dermatology, looked at 50 participants with Covid toes and 13 with similar frostbite lesions that appeared before the pandemic.
They found that one mechanism behind both types of the disease is that the body creates an immune response with high levels of certain autoantibodies that falsely target and respond to a person’s own cells and tissues, as well as the invading virus.
They also found an overlap with type I interferon, a key protein in the antiviral response.
In addition to the immune system, cells that line blood vessels that supply the affected areas also appear to play a crucial role in causing Covid toes and chilblains.
The study’s lead author, Dr. Charles Cassius said the research has allowed a deeper understanding of the condition.
“The epidemiology and clinical features of chilblaz-like lesions have been extensively studied and published, but little is known about the pathophysiology involved,” he said.
“Our study provides new insights.”