Abstract
Linked Article: Frumholtz et al. Br J Dermatol 2021; 185:1176–1185. Chilblains are skin lesions that affect the hands and feet, and usually appear in winter. They are frequent, non‐cancerous, mostly of unknown cause/spontaneous (idiopathic), sometimes painful and generally develop into flare‐ups. They affect young people worldwide. Usually, there is no need for treatment. Outbreaks of chilblain‐like lesions (CLLs) during the COVID‐19 pandemic have been reported and are potentially related to infection with the COVID‐19 virus, SARS‐CoV‐2. The aim of the study was to compare CLLs with seasonal chilblains, defined as cold‐induced sporadic chilblains occurring before the COVID‐19 pandemic. This observational study was carried out in April 2020 at Saint‐Louis Hospital (Paris, France). Fifty patients referred to us with CLLs that appeared during the COVID‐19 pandemic were included in the study. We excluded patients with a history of chilblains. A systemic immune response associated with the autoantibodies IgA and anti‐neutrophil cytoplasmic antibodies (ANCA) in the blood, and a specific immunological response (a high level of type I interferon) was seen in patients with CLL, compared with people without CLLs. Other indicators (biomarkers) of vascular dysfunction were found in the blood of those with CLLs. Our findings support the suggestion that there is a specific immunological response and change in the vascular system that leads to outbreaks of CLLs.