The most common symptoms of COVID-19 are fever, dry cough, and loss of taste and smell. Other commonly seen signs include headache, muscle and joint pain, nasal congestion, and fatigue.
A less common symptom is rashes of various forms. These have been slower to report, partly due to the diversity that has emerged in COVID-19 patients, making it more challenging to establish a consistent relationship.
Nevertheless, it is important to know how COVID-19 affects the skin. A recent study found that skin rashes were the first symptom to appear for 17 percent of COVID-19 patients with multiple symptoms, and for 21 percent of patients rashes were the only symptom. aca.
By being able to recognize the effects of COVID-19 on the skin, cases may be seen earlier – or even completely picked up in people who are otherwise asymptomatic. This may help limit transmission.
With that in mind, here are the four main types of skin changes to look at, and the possible reasons why they happen.
Chilblain-like injuries
These are red, swollen or blistering skin lesions that mainly affect the toes and soles of the feet, suddenly known as “COVID toes”. Over one or two weeks, the wounds become even worse and smooth, after which they heal on their own without treatment.
A large number of these lesions have been observed, particularly in adolescents and young adults with few COVID-19 symptoms. They make up the majority of skin issues related to the virus. In two international reports on different types of COVID-related skin conditions, about 60 percent of patients with skin complaints reported these injuries.
However, because these injuries are associated with mild disease, many of the patients who accompanied them in these studies were not eligible for COVID-19 testing at the time, and 55 percent were otherwise asymptomatic.
Thus although the rapid increase of these lesions during the pandemic appears to be associated with COVID-19, direct confirmation of this has not been established. It is possible that they are caused by another related feature.
It’s just vague when they appear. In a study analyzing 26 patients with suspected COVID-related skin changes, 73 percent reported cell-like injuries. None of the patients had respiratory symptoms and were all COVID-negative at the onset of their illness. An explanation is that these lesions appear only after a long delay – up to 30 days after infection.
The cause of these injuries was debated. The culprit could be type 1 interferons, proteins that regulate the antiviral properties of the immune system.
The theory is that high production of these interferons could cause patients to clear the coronavirus quickly, but also cause blood vessel injuries and increased inflammation. This would explain the coincidence of mild or unstable disease, negative tests and skin damage.
Another theory is related to ACE2, the molecule used by the coronavirus to enter cells. It is present on many cell types, including those in the sweat glands, which are common on the palms of the hands and soles of the feet. This could make these areas particularly vulnerable to virus damage.
Alternatively, damage to blood vessels, caused either by the immune response or the virus, may lead to cell death and multiple blood clots in the toes.
Broth maculopapular
This term describes both flat and raised areas of colored skin. A study of 375 patients in Spain found that 47 percent of patients with COVID-related skin changes had this rash.
These were associated with more severe COVID-19 symptoms, and were found mostly on the stock in middle-aged to elderly patients. They tended to last 7-18 days, appearing 20-36 days after infection.
A suggested reason is that the body’s immune system is overwhelmed. In some patients, hyperinflammatory rate occurs 7-10 days after infection, leading to tension damage and, possibly, disease and more severe death.
Hives
They are also called urticaria, which are high areas of itchy skin. In a study involving four hospitals in China and Italy, 26 percent of COVID-19 patients complained of skin changes with kidneys.
Bees usually appear before or present at the same time as other signals, making them useful for diagnosis. They are more common in middle-aged patients and are associated with more severe disease. Viral infections are a stimulus of cataracts, as they cause cell breakdown and histamine release through the release of a reaction in the immune system.
However, it is important to remember that kidney is also a known side effect of many drugs used to treat COVID-19, such as corticosteroids and remdesevir.
Vesicular injuries
These are clear bags full of beer under the skin, similar to those found in chicken pox. They are less common compared to the above skin conditions: in the previously cited Spanish study of COVID-19-related skin changes, only 9 percent of patients had the bones sin.
However, they are thought to be a more specific marker of someone with COVID-19 than those already listed, and are therefore more useful for diagnosis. They appear to be present in patients with mild infection about 14 days after infection.
They are thought to be caused by persistent inflammation, with antibodies invading the skin and damaging its layers, resulting in sacs full of fluid. 
Vassilios Vassiliou, Senior Clinical Lecturer in Cardiovascular Medicine, University of East Anglia and Subothini Sara Selvendran, Visiting Researcher in Medicine, University of East Anglia.
This article is republished from The Conversation under a Creative Commons license. Read the original article.