An unusual rise in the number of chilblains being diagnosed in France may be connected to the COVID-19 pandemic, dermatologists say.

The French researchers report results of a retrospective study in 277 people (50% male, median age 27) seen in outpatient private dermatology practices between 18 March and 9 April.

As outpatients seeing a dermatologist, few patients (12%) had been tested for SARS-CoV-2 but of those who were tested, 74% were positive. A further 115 patients had symptoms such as fever, respiratory symptoms, anosmia or ageusia suggestive of COVID-19 or had been in close contact with a person with known infection.

More than half the patients had acral lesions, with three-quarters of these being chilblains, the doctors wrote in a letter to the Journal of the American Academy of Dermatology.