While dry cough, fever and shortness of breath are the classic symptoms of Covid-19 infections, some people also experienced redness and swelling of the hands and toes known as chilblain-like lesions. A new study published in the British Journal of Dermatology explores the underlying mechanisms involved in such conditions, also known as "COVID-19 toes".
In the study, researchers at the University of Paris conducted blood and skin tests and found that two parts of the immune system, which involve mechanisms to fight Covid-19 might be the reason, BBC reported.
One is an anti-viral protein called Type-1 interferon and the other is a type of antibody that mistakenly attacks the person's own cells and tissues, not just the invading virus. Cells lining small blood vessels supplying the affected areas are also involved, according to researchers from the University of Paris, France.
The team studied 50 people with suspected Covid toe in the spring of 2020, and 13 others with similar chilblains lesions that were not linked to Covid infections because they occurred long before the pandemic began, the report said.
"For most -- like the regular chilblains typically seen during cold spells and in people who have problems with circulation -- the lesions usually go away on their own. But some may need treatment with creams and other drugs," Ivan Bristow, UK podiatrist was quoted as saying.
"The confirmation of the cause will help to develop new treatments to manage it more effectively," he added.
COVID-19 toe, which appears to be a side-effect of the body switching into attack mode to fight off the virus, can happen at any age but affects children and teenagers more commonly.
For some it is painless but the rash can be extremely sore and itchy with tender blisters and swelling. Some, however, develop painful raised bumps or areas of rough skin and have pus. People suffering from the condition often have none of the classic COVID-19 symptoms which can persist for months or weeks.
The Covid toe condition was very frequent during the early phase of the pandemic but has become less common now. That might be down to more people being vaccinated or having some protection against Covid-19 from past infections, Veronique Bataille, a consultant dermatologist and spokeswoman for the British Skin Foundation, was quoted as saying.
