What Are 'COVID Nails'?

COVID-19 has been linked to a variety of unusual skin and hair conditions. To add to the list, there are now cases of so-called "COVID nails" in some people who had been sick with the virus.

However, skin experts say that nail changes are not necessarily an indication that you previously had COVID-19 and that you do not need to be worried if you have them.

What Are ‘COVID Nails’?

On Twitter, U.K.-based epidemiologist Tim Spector posted an image of nails with deep ridges, writing that “COVID nails are increasingly being recognised as the nails recover after infection and the growth recovers leaving a clear line.” Spector added that the lines "can occur without skin rashes and appears harmless."

Harvey Lui, MD, a professor of dermatology and skin science at the University of British Columbia and the Vancouver Coastal Health Research Institute, tells Verywell that “COVID nails” are actually a condition called Beau’s lines.

Lui says that the lines can appear whenever the body experiences major stress. This could be in the form of an infection or even a severe psychological or emotional event.

Marisa Ponzo, MD-PhD, FRCPC, DABD, a certified dermatologist and head of the division of dermatology at St. Paul's Hospital, tells Verywell that some medications (e.g. chemotherapy) can also cause Beau’s lines, as can an injury to the nail.

“When there are a few or one nail involved, [Beau’s lines] is most likely due to trauma,” Ponzo says. “When the linear, horizontal depression occurs on multiple nails, we think of a systemic (or internal) cause.”

Why Beau's Lines Happen

Beau’s lines occur when nail growth near the cuticle (the nail matrix) temporarily stops. A person's nails may stop growing and thin out when they are sick because their body needs to conserve its energy and focus on healing.

According to Lui, during a COVID-19 infection, "the body is maintaining its core functions—you want your heart to keep going, you want your kidneys to keep going," he says. "So that means that the nails will slow down their growth because they're not viewed as being essential to life."

When the body is recovering and the nail growth pattern is restored, the nail will thicken again. This causes the formation of ridges. The pattern of stop-and-start growth explains why Beau’s lines are seen in some people who are recovering from COVID.

Are Beau's Lines A Sign of COVID-19 Infection? 

“If you see Beau's lines and you had COVID-19 symptoms a month prior, then it's possible that it's related to COVID-19," Julia Carroll, MD, a dermatologist at Compass Dermatology in Toronto, tells Verywell. "But it's not a reliable way to diagnose COVID-19."

Beau’s lines appear once a person is recovering from whatever ailment they had. That's why Lui uses nail ridges to help him piece together what may have happened to a patient months before they got sick. It also gives him a more complete picture of their overall health.

“As a dermatologist, I look at patients’ hands and nails because the nails can tell you a lot about someone's health," Lui says. "It's kind of like detective work. If I see a little groove on their nail, I ask, ‘Did something big happen to you about two or three months ago?’ And they go, ‘Yeah, as a matter of fact, I had a major operation.’”

Other Conditions and COVID-19

Carroll points out that several skin conditions are already associated with COVID-19, including a generalized maculopapular rash, COVID toes, hives, blisters, and skin discoloration like livedo reticularis. Some of these conditions appear during the illness while others, like Beau's lines, show up later.

Lui says that some COVID-19 patients have also experienced hair shedding or hair loss. Telogen effluvium—a condition that causes hair loss after a stressful event—is occurring at higher rates in communities that have been harder hit by the pandemic.  

“They might have hair shedding either because of the severe psychological and emotional stress of having to deal with COVID or also from having COVID itself,” Lui says.

The hair changes are similar to nail changes. Lui explains that “once the [illness] passes, hair growth picks up again.”

Carroll says that ridges or unusual-looking nails are not a definitive sign of a previous COVID-19 infection. Many illnesses can cause Beau’s lines, such as influenza, Raynaud's syndrome, and Kawasaki disease.

Do You Need to Worry About Beau's Lines?

Having COVID nails does not mean that you had COVID-19. They also do not mean that your nails are permanently damaged. While they might look odd, Ponzo says that the condition "is reversible and the nail eventually grows out."

Carroll stresses that Beau's lines are not something you need to be concerned about. But you might be waiting a while for your nails to look more normal. "A fingernail typically takes six months to grow out, while a toenail can take up to 18 months," she says.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.