While most people are familiar with the "telltale symptoms of a Covid-19 infection," some people develop "uncommon manifestations" of the disease, including "hairy tongues, purple toes, welts that sprout on their faces," and more, Dani Blum writes for the New York Times.

Why some people experience 'uncommon manifestations' of Covid-19

Nearly three years into the Covid-19 pandemic, most people recognize the "telltale symptoms of a Covid-19 infection," including "a ragged ache in your throat, a pernicious cough, congestion, fever and full-body exhaustion," Blum writes.

However, a small subset of people reported less common symptoms like "hairy tongues, purple toes, welts that sprout on their faces," and more, she adds.

"Every infectious disease has common and uncommon manifestations," said Mark Mulligan, an infectious disease specialist at NYU Langone Health. According to Mulligan, as experts continue learning more about the coronavirus, they may gain a better understand of what causes these uncommon symptoms.

Since the beginning of the pandemic, experts have tried to find the underlying cause of many puzzling symptoms, including the loss of taste and smell, and disrupted menstrual cycles, which some women experienced after vaccination.

In a study of more than 60,000 people who reported their symptoms after testing positive for Covid-19, researchers found that a small percentage of participants experienced ringing in their ears, sore eyes, rashes, red welts on their faces or lips, hair loss, and unusual joint pains.

Separately, a larger study of over 600,000 people in Britain showed that some Covid-19 patients also developed several uncommon maladies, including purple sores and blisters on their feet and numbness across their bodies.

While experts do not fully understand why some people develop unusual symptoms and others do not, Mulligan noted that genetics and vaccination status could play a role. In rare cases, the virus enters the bloodstream, making it possible for the virus to enter other organs and trigger symptoms outside of the respiratory system, he added.

Kelly Gebo, an infectious disease specialist at Johns Hopkins Medicine, noted that antiviral treatments could ease symptoms for some people.

Separately, Peter Chin-Hong, an infectious disease specialist at the University of California, San Francisco suggested that inflammation could also be a potential cause. According to Chin-Hong, if the virus travels through the bloodstream and impacts other areas of the body, immune cells could cause those areas to become inflamed and trigger other symptoms.

Chin-Hong also suggested that the stress associated with a Covid-19 infection could also cause symptoms like hair loss and hives.

How to address 5 uncommon Covid-19 symptoms

Unfortunately, there are not set rules for treating these unusual symptoms. "We have definitive guidelines on how to treat shortness of breath," Gebo said, "but we don't have definitive guidelines on these."

However, experts do have some insight into the cause—and treatment—of some of these symptoms, including:

A hairy tongue

Before Covid-19 emerged, doctors saw patients who developed hairy tongue due to viral infections, smoking, antibiotic use, and poor hygiene. "It's more common than people think," Chin Hong said.

"People with hairy tongue can use a tongue scraper or toothbrush to scratch away those tongue cells, and they can make sure to practice good oral hygiene to prevent additional buildup," Blum writes.

Pins and needles

When people experience nerve tingling on their skin, it may be caused by nerve inflammation triggered by immune cells trying to combat an infection, Chin-Hong said. According to Gebo, the virus may also cause damage to peripheral nerves, including those that connect to your hands and feet.

While this symptom typically resolves in a few days, it can be persistent. For persistent nerve pain, Marc Sala, co-director of the Northwestern Medicine Comprehensive Covid-19 Center suggests consulting a doctor.

Skin rashes

According to the American Academy of Dermatology Association, itchy bumps, chickenpox-like blisters, rashes that form lacy patterns, and raised bumps have all been linked to Covid-19. 

If you have a rash that lasts beyond your recovery from the virus, Sala recommends consulting a dermatologist.

Hair loss

Shilpi Khetarpal, a dermatologist at Cleveland Clinic, noted that it is still unclear whether the virus itself or the associated stress causes hair loss in some people. However, "It's not scarring—it comes back," she said. "It just needs time."

Covid toes

Currently, experts are unsure what causes "the frostbite-like rash and blisters that form on some people's feet and fingers after they become infected, causing toes and the tips of fingers to become swollen and purple," Blum writes.

According to Sala, microvascular clots, which block the blood supply to the smallest blood vessels in the body, could be responsible for the discoloration. Typically, this symptom resolves on its own.

"We're still learning about Covid," Mulligan said. "We don't understand everything." (Blum, New York Times, 11/16)