More than two years after the start of the pandemic, hundreds of thousands of Covid cases continue to be reported around the world every day.
With the emergence of new variants, the symptoms of covid have also evolved.
Initially, for example, the United Kingdom’s National Health Service (NHS), the British SUS, considered fever, cough and loss or alteration of smell or taste as the main symptoms that could be indicative of the disease.
Now, recently updated NHS guidance also suggests that we should be on the lookout for symptoms including a sore throat, a stuffy or runny nose and a headache.
But what about some of the less obvious signs and symptoms? From skin lesions to hearing loss, new studies are increasingly showing us that the symptoms of covid are not limited to the common cold or flu.
1. Skin injuries
Covid-related skin problems are not uncommon. In fact, a UK study published in 2021 found that one in five patients had only a rash and no other symptoms.
Covid-19 can affect the skin in many ways. Some people may have a maculopapular rash (flat, raised lesions), while others may have hives (raised, itchy lesions).
The so-called “covid fingers” are characterized by red, swollen or blistered skin lesions on the toes. This symptom is more common in teenagers or young adults with mild or no symptoms.
Most skin lesions caused by covid tend to disappear after a few days or, in some cases, a few weeks, without the need for any specific treatment.
However, if the skin itches or hurts a lot, it is recommended to see a doctor, who may recommend applying a cream.
2. “Covid nails”
During an infection, including SARS-CoV-2 (the virus that causes covid-19), our body naturally tries to express that it is under an unusual amount of stress.
“Covid nails” include changes such as:
- Beau lines: These are horizontal indentations that occur at the base of fingernails or toenails when there is a temporary stop in nail growth due to physical stress on the body.
- Leukonychia striatum: These are horizontal white lines that appear on the nails, although this can be caused by abnormal protein production in the nail bed.
- A red crescent pattern that develops at the base of the nails (the mechanism underlying this change is unclear).
Data on how many people have these nail problems is limited, but it is estimated that they can affect 1% to 2% of Covid patients.
“Covid nails” tend to appear in the days or weeks after infection, as the nails grow. While it can be painful at first, most nails tend to return to normal within a few weeks.
While these changes could be indicative of covid, they could also be caused by different things. For example, Beau’s lines can be a result of chemotherapy or another infection.
3. Hair loss
Hair loss is perhaps an underestimated symptom of Covid-19, often occurring a month or so after acute infection.
In a study of nearly 6,000 people who contracted the new coronavirus, hair loss was the most common post-covid symptom, reported by 48% of participants.
Hair loss was especially prevalent among people who had severe Covid and in white women.
This is believed to be because the hair “feels” the stress on the body, leading to excessive shedding.
In fact, hair loss can also be triggered by other stressful events like childbirth. The good news is that over time your hair will grow back normally.
4. Hearing loss and tinnitus (or tinnitus)
As with other viral infections such as the flu and measles, covid has been found to affect the cells of the inner ear, with hearing loss or tinnitus (a constant ringing sensation in the ear) sometimes after infection.
In a study involving 560 participants, hearing loss was reported in 3.1% of Covid-19 patients, while tinnitus occurred in 4.5% of cases.
Another study, with 30 people diagnosed with covid-19 and 30 who did not have the disease, none with pre-existing hearing problems, researchers found that covid-19 was associated with damage to the inner ear, leading to hearing problems at frequencies taller.
Although for most patients this resolves on its own, cases of permanent hearing loss related to Covid have been reported.
Why do these symptoms appear?
We don’t understand exactly what causes these symptoms, but we do know that the most important role is played by a process called inflammation.
Inflammation is our body’s natural defense mechanism against pathogens; SARS-CoV-2 in this case. It involves the production of “cytokines” (also called cytokines), proteins important in controlling the activity of immune cells.
Excessive production of these proteins, as part of the inflammation triggered by Covid infection, can cause sensory deficits, which could explain why some people experience hearing loss and tinnitus.
It can also modify the capillary networks, very small blood vessels that supply blood to organs, including the ears, skin and nails.
The symptoms we describe here are not unique to covid infection. That said, if you notice any of these symptoms, you should get tested for covid, especially if you are in an area where the virus is circulating.
You can also contact your GP, especially if symptoms get worse or cause significant discomfort. At the same time, rest assured that most of these symptoms are likely to improve over time.
*Vassilios Vassilou is Professor of Cardiac Medicine, Ranu Baral is Visiting Research Fellow (FY2 Academic Foundation) and Vasiliki Tsampasian is SpR and NIHR Cardiology Academic Clinical Fellow at the University of East Anglia, UK.
This article was originally published on the academic news site The Conversation and republished here under a Creative Commons license. Read the Spanish version here.