The main signs of “Covid-19” are known to include: fever, cough, fatigue, loss of taste and smell, and signs of the disease have also been observed on the skin.
But another part of the body appears to be affected by the virus: the fingernails. After contracting COVID-19, the nails of a few patients appear deformed after several weeks – a phenomenon dubbed “Covid nails”.
One symptom included a red half-moon pattern forming a convex band over the white area at the base of the nails. This appears to appear earlier than other nail complaints related to Covid, with patients noticing it less than two weeks after diagnosis.
Red, half-moon-shaped nail patterns are generally rare, and have not previously been seen near the base of the nail. Therefore, the appearance of this pattern in this way could be exclusively an indicator of infection with “Covid-19”.
The mechanism behind the half-moon pattern is still unclear. A possible cause could be damage to the blood vessels associated with the virus itself. Alternatively, it may be due to the immune response against the virus that causes small and discolored blood clots.
More importantly, these signs do not appear to be alarming, because patients do not have symptoms – although it is unclear how long they have them, they have lasted from one to more than four weeks in the reported cases.
Signs of physical stress
A small number of patients also found new horizontal indentations at the bases of the fingernails and toenails, which are known as “Poe’s lines”. They tend to appear four or more weeks after infection with “Covid-19”.
Poe lines occur when there is a temporary interruption in nail growth due to physical stress on the body, such as infection, poor diet, or side effects of medications such as chemotherapy drugs. While it is plausible that it was caused by “Covid-19”, it is certainly not an exclusive symptom of the disease.
With nails growing between 2 and 5 mm per month on average, “Bo’s lines” tend to become noticeable after four to five weeks of physical exertion.
So the timing of the stressful event can be estimated by looking at how far the “Poe lines” are from the base of the nail. There is no specific treatment for Bo’s lines, as they eventually tend to grow if the underlying condition resolves.
Currently, the available evidence indicates that there is no association between the severity of COVID-19 infection and the type or extent of nail changes.
Other unusual results
Researchers have recorded some other unusual incidents as well, in which a patient’s nails retracted from the base of the nail and eventually fell out, three months after her injury. This phenomenon is known as onychomadesis, and is believed to occur for similar reasons as the appearance of “Poe lines”.
The patient did not receive treatment for these changes as new healthy nails can be seen growing under the ones that separated, indicating that the problem is starting to resolve itself.
Another patient, 112 days after his positive test result, experienced a change in color at the tips of his nails. No treatment was given, and the mechanism behind this is unknown.
In a third case, the patient’s nails appeared to have horizontal white lines that do not disappear with pressure, known as “Mays lines” or transverse leukemia. It appeared 45 days after testing positive for “Covid-19”.
“Mays lines” are thought to be the result of abnormal production of proteins in the nail bed due to systemic disorders.
In fact, even with the ‘Bo lines’ and the red half moon pattern, there is still a long way to go to confirm a specific link between these changes and COVID-19, as well as the mechanisms behind them. For all of these cases, we will need to report several cases before we can say for sure that there is a link.
In addition, even if there is a causal link, it is important to remember that not all COVID-19 patients have these nail conditions. Some of these abnormalities may not necessarily mean that someone has COVID-19. At best, we should consider these as possible indicators of previous infection – not conclusive evidence.
It is noteworthy that the report was prepared with the contribution of Vasilios Vasilio, Senior Clinical Lecturer in Cardiovascular Medicine, University of East Anglia; and Nikhil Agarwal, a medical researcher, University of East Anglia, and Soputhini Sara Sylvandran, a medical researcher from the University of East Anglia.
Source: Science Alert