Nails appear discoloured or misshapen a number of weeks – a phenomenon that’s been dubbed “COVID nails”.

One symptom is a red half-moon pattern that forms a convex band over the white area at the base of fingernails. This seems to present earlier than other COVID-related nail complaints, with patients noticing it less than two weeks after being diagnosed. Multiple cases have been reported – but not many.

Red half-moon nail patterns like this are generally rare, and previously haven’t been seen so close to the nail base. So having this pattern appear like this could exclusively be an indication of a COVID-19 infection.

A few patients have also found new horizontal indentations in the bases of the nails of their fingers and toes, which are known as Beau’s lines. These tend to appear four weeks or more after a COVID-19 infection.

Beau’s lines occur when there is a temporary interruption in nail growth due to a physical stress on the...