At the very beginning of the covid-19 epidemic, researchers at Massachusetts General Hospital (in the United States) highlighted a new symptom of persistent Covid-19: bluish / purplish toes. Scientists (who had worked in collaboration with American dermatologists from the League of Dermatological Societies and the American Academy of Dermatology) explained that between April and August 2020, 1000 dermatological manifestations of the Sars-Cov-2 coronavirus infection had been recorded in 39 countries around the world. And that among these 1000 patients, half had bluish / purple toes and 16% of them had even been hospitalized for this reason …
To understand the origin of this epidemic of lesions resembling frostbite, researchers at Saint-Louis Hospital in Paris had blood and skin tests taken on about fifty patients with this symptom and on 13 other patients with been treated for frostbite long before the start of the pandemic. The results of their study, published in the British journal of dermatology, suggest that suggest that two parts of the immune system come into play: uis an antiviral protein called type 1 interferon and a type of cytoplasmic antibody that mistakenly attacks the cells and tissues of the person affected by covid-19.
This symptom seems to have affected patients of all ages but especially children and adolescents. “In some patients with Covid-19, inflammation develops in the toes, causing the skin and swollen toes to become red in color – they may then turn blue or purple, explained dermatologist Dr. Esther Freeman. This symptom lasts 15 days on average; but in patients with persistent Covid-19, it can last for several months.“
The clinical manifestation of strong immunity
Previous work from the Center hospitalier universitaire vaudois (CHUV) in Switzerland also showed that “blue toes” were not a specific symptom of covid-19, but the sign of a strong immunity that wakes up during a contact with the virus and prevent it from establishing itself in the body.
“Everything would play out at the level of” type 1 interferons “, a group of antiviral proteins. A very strong activation of these would thus allow a natural barrier against SARS-CoV-2”, explained Professor Michel Gilliet, head of the dermatology department of the CHUV, at the origin of this hypothesis.
Dermatological manifestations are the fourth major symptom of the Sars-Cov-2 coronavirus – along with fever, cough, and loss of taste and / or smell.
Source:
- Type I interferon response and vascular alteration in chilblain-like lesions during the COVID-19 outbreak, British journal of dermatology, October 2021
- Covid toes, skin expression of innate resistance to SARS-CoV-2, Dermatology, March 2021
Read also :
- Why do some Covid patients not recover?
- Covid-19: 50% of transmissions occur before the onset of the first symptoms
