Half and half nail, is it a marker of severe COVID-19 infection?

Several cutaneous manifestations have been described during COVID-19 infection, however ungual signs remain neglected. Half and half nail or Lindsay nails is a rare clinical finding, frequently seen in chronic renal failure, and many other disorders.

We report 2 cases of half and half nail aspect occurring during severe COVID-19 infection, without a history of kidney disease, suggesting that 'Lindsay Nails' can be considered as a severity marker.

An increasing number of nails changes has been reported since the COVID-19 outbreak. As well as the acral manifestations of COVID-19, the acute appearance of Half and half nail sign can be explained by a vascular involvement that may induce a transient matrix injury.

We report the first description of acute onset of half and half nails during COVID-19 severe infection in 2 patients without a history of kidney failure or any other condition previously described, suggesting that it can be considered as a severity marker.