The incidence of chilblains in one US state increased substantially during the pandemic, but the cause appears to be more related to changes in behaviour than COVID-19, according to a study.

Case reports have linked the pandemic to an elevated occurrence of chilblains, but until now there have been no epidemiologic studies to assess the association, the researchers noted in JAMA Dermatology.

They examined data on 1,319 patients who were diagnosed with chilblains before and during the COVID-19 pandemic.

They identified 780 cases from April to December 2020 and 539 cases during the same months from 2016 to 2019.