More than two years after the pandemic, hundreds of thousands of COVID cases are still recorded worldwide every day.
With the emergence of new variants, symptoms of COVID have also developed. Initially, the NHS considered fever, cough, loss or altered sense of smell or taste as the main symptoms that could indicate infection with the Covid virus. Now, recently updated NHS guidelines suggest looking for symptoms including sore throat, stuffy or runny nose and headache.
But what about some of the more vague signs and symptoms? From skin lesions to hearing loss, emerging data increasingly shows us that symptoms of COVID can go beyond what you might expect from the common cold or flu.
Read more: What are the symptoms of Omicron?
1. Skin lesions
Skin complaints associated with COVID are not uncommon. In fact, a British study published in 2021 found that one in five patients showed a rash and had no other symptoms.
Covid disease can affect the skin in several ways. Some people may have a widespread papular rash (flat or raised areas of discolored skin), while others may develop urticaria (raised areas of itchy skin).
Meanwhile, “COVID toes” describes red, swollen or ulcerated skin lesions on the toes. These symptoms are more common in adolescents or young adults with mild or no symptoms.
Most COVID skin lesions tend to heal after a few days, or in some cases a few weeks, without the need for any specialized treatment. If the skin is very itchy or painful, you can consult your GP or dermatologist, who may recommend a treatment such as a cream.
2. Covid nails
During infection, including SARS-CoV-2 (the virus that causes COVID-19), our bodies naturally try to express that they are exposed to an unusual amount of stress. They can do this in many weird and wonderful ways, including through our fingernails. COVID nails include changes such as:
Poe’s lines – horizontal indentations that occur at the base of the fingernails or toenails when there is a temporary interruption in nail growth due to physical stress on the body
Mays lines – horizontal white lines that appear on the nails, thought to be caused by the abnormal production of proteins in the nail bed
A red half-moon pattern develops at the base of the nails (the mechanism behind this change is unclear).
Data on the number of people with COVID toenails is limited, but it is estimated that it may reach 1-2% of COVID patients.
COVID nails tend to appear in the days or weeks after infection with the COVID virus as nails grow. Although it may be painful at first, the vast majority of it tends to return to normal within a few weeks.
Notably, while these changes may be indicative of COVID, they may be caused by different things. For example, Beau’s lines could be secondary to chemotherapy or another infection.
3. Hair loss
Hair loss is perhaps an indescribable symptom of COVID-19, and usually occurs a month or more after an acute infection. In one study of nearly 6,000 people who had previously had COVID, hair loss was the most common post-COVID symptom, reported by 48% of participants. It was especially prevalent among people with severe COVID and white women.
This is thought to be caused by the hair ‘sensing’ the tension in the body, which leads to excessive hair loss. In fact, hair loss can also be caused by other stressful events, such as childbirth. The good news is that over time, hair returns to normal.
4. Hearing loss and tinnitus
As with other viral infections, such as influenza and measles, COVID has been found to affect the cells of the inner ear, with sometimes hearing loss or tinnitus (a persistent ringing sensation in the ear) after infection.
In a review study with 560 participants, hearing loss occurred in 3.1% of patients with COVID, while tinnitus occurred in 4.5%.
In one study of 30 people diagnosed with COVID, and 30 people who did not—no pre-existing hearing problems—researchers found that COVID was associated with inner ear damage resulting in impaired hearing at higher frequencies. While for the vast majority of patients this resolves on its own, cases of permanent hearing loss associated with COVID have been reported.
Why all these symptoms?
We don’t understand exactly what causes these symptoms, but we do know that the most important part is 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” – proteins important in controlling the activity of immune cells.
Excessive production of these proteins, as part of the inflammation caused by COVID infection, can cause sensory deficits, which likely explains why some people develop hearing loss and tinnitus. It can also disrupt the networks of capillaries, the very tiny blood vessels that supply blood to organs including the ears, skin, and nails.
Read more: Four COVID-related skin complaints everyone should watch out for
The symptoms we describe here are not exclusive to COVID infection. However, if you notice any of these symptoms, it would be a good idea to consider a COVID test, especially if you are in an area where COVID is common.
You can also call your doctor, especially if your symptoms are getting worse or are causing you significant discomfort. At the same time, you can rest assured that most of these symptoms will likely improve over time.