You could find out if you’ve previously had Covid by looking at your nails, experts suggest.
A handful of strange changes in the finger and toe nails have been documented over the course of the pandemic.
Experts say nails are similar to the skin in that they can give clues about a person’s health.
And skin issues are already known to affect up to 20 per cent of people with COVID.
But people rarely inspect their nails – sometimes covered in polish – and so may be unaware of the subtle differences caused by the virus.
Fingernails grow in roughly six-month cycles, therefore any change in appearance caused by the coronavirus may show with a delay.
Nail abnormalities can be the result of all sorts of problems, including vitamin deficiencies, skin conditions, diabetes or trauma – such as shutting your hand in a door.
But dermatologists have suggested it is not a coincidence that a number of people have had nail changes after a positive Covid test.
“There’s another part of the body where the virus appears to have an impact: the fingernails,” experts wrote in the Conversation.
“Currently, the available evidence suggests that there’s no association between the severity of Covid-19 infection and the type or extent of nail changes.”
Read on to find out if you’ve had any of the problems:
1. Lines
Some experts have flagged that Covid survivors have horizontal lines across the nails following infection.
This was highlighted by Prof Tim Spector, the lead researcher on a major symptom study between King’s College London and the health company ZOE.
Known as Mees lines, it can also be seen as a result of heart failure, infectious diseases like malaria and lymphoma cancer.
But with no other clear causes, it could be the result of Covid.
A paper reported the case of a 47-year-old Spanish man last June, who had developed thick white bands on the centre of his nails 45 days after testing positive for Covid.
The authors, from Spain, said they thought such nail alterations in the general public were “probably unreported”.
2. Ridges
Similar subtle ridges in the nails – medically called beau lines – have been reported in Covid patients.
It was recently described by Canadian doctors in a 45-year-old man.
He had a groove across all his fingernails and toenails, about 5mm from the nailbed.
The placement of the groove was deemed reflective of the fact the man tested positive for Covid three months prior, experts said.
3. Red half moon
Everyone has a half moon shape at the bed of their nails.
In some people, this has been topped with a red colour following Covid.
“Multiple” cases have been seen, according to US and Mexican researchers who described the case of a 37-year-old woman.
She saw a red band appear over her crescent moon shape just two days after developing Covid symptoms.
It only lasted for one week before returning to normal.
Researchers said it could be inflammation in the vascular system at the heart of the strange symptom.
4. Orange tips
Another sign of Covid disease could be orange tips of the nail.
This was seen in an elderly woman who caught the bug while in a care home in Italy.
The discoloration did not develop until 16 weeks after her diagnosis and lasted for at least a month later.
Experts said they ran tests which proved the presence of Covid antibodies, adding that the shape of the colouring suggested the cause was “systemic” – meaning in this case, caused by disease.
They wrote: “It is notable that nail abnormalities can provide useful information regarding underlying systemic diseases.
“For instance, yellow nails and nail bed telangiectasia can be signs of chronic obstructive pulmonary disease, while clubbing and melanonychia may be seen in viral infections.”
5. Nail lifting
Onychomadesis has also been theorised to be caused by coronavirus infection.
It looks as though the nail has separated into two, often called “nail shedding”, thought to occur because of a temporary pause in nail growth.
Already the condition has been seen with other infections, most notably foot-and-mouth, autoimmune diseases and medications.
One woman was described in the literature as the “first” to have the conditions after Covid – for which she was hospitalised for three months prior.
Docs said her old nails had “detached” and new ones were growing from the base.
They wrote: “Nails were thought to be reservoir for the virus with a potential to play a role in transmission by some patients, although this remains unclear.”
