A new term is circulating after a scientist in the U.K. said he was receiving anecdotal reports of COVID nails, or horizontal lines appearing across the nails of coronavirus survivors several months after infection. Tim Spector, a professor of genetic epidemiology at King’s College London, is one of the experts behind the ZOE COVID Symptom Study app, and first flagged that users were reporting “COVID nails” on his Twitter page.
“Do your nails look odd?” he wrote on May 3. “COVID nails are increasingly being recognized as the nails recover after infection and the growth recover leaving a clear line. Can occur without skin rashes and appears harmless.”
In response, Spector said he was “getting some nice COVID nail pictures,” and additional reports of “nail ridges 4-8 weeks post-vaccine.” He later told a follower that the nail ridges, also known formally as Beau’s lines, can occur after any infection, trauma, or disease “that upsets the immune system.”
Beau’s lines are grooves that run horizontally across the nail and can occur when growth at the area under the cuticle is interrupted by injury or severe illness, according to the MayoClinic. Previous conditions associated with the occurrence include uncontrolled diabetes, peripheral vascular disease, scarlet fever, measles, mumps and pneumonia. It can also signal zinc deficiency.
There is no specific treatment for the phenomena, and it usually self-resolves if the underlying condition is cleared.
Others have documented nail changes associated with COVID-19 infection, like the Canadian Medical Association, which published a case report on the occurrence in its Sept. 2020 journal. In the report, researchers detailed a 45-year-old man who presented with a horizontal groove over his fingernails and toes. Three and half months prior to documenting the change, he had been diagnosed with COVID-19. His multiple symptoms included a fever but he did not require hospitalization.
The researchers concluded that “the distance of the Beau lines from the proximal nail fold in our patient reflects the timing of severe acute respiratory syndrome coronavirus infection.”
Spector said it’s not clear if the occurrence correlates to disease severity, “but it would be more helpful if it wasn’t,” he told Business Insider.
“If we get enough numbers that are associated with asymptomatic COVID-19, that’s a cheap antibody test,” he told the news outlet. “People just need to look down at their nails.”