key: cord-267612-1h7xpkbe
authors: Lipsker, Dan
title: A chilblain epidemic during the COVID-19 pandemic. A sign of natural resistance to SARS-CoV-2?
date: 2020-06-06
journal: Med Hypotheses
DOI: 10.1016/j.mehy.2020.109959
sha: 
doc_id: 267612
cord_uid: 1h7xpkbe

nan

A chilblain epidemic during the COVID-19 pandemic.

A sign of natural resistance to SARS-CoV-2?

Dan Lipsker 1,2 , MD, PhD Since the start of the COVID-19 pandemic, "epidemics" of chilblains or chilblain-like acral lesions have been reported in the social media, the general press and the medical literature in Italy, Spain, the UK and France (1) (2) (3) (4) (5) . This was also our experience in the region of Alsace which was the earliest to be hit hard by the COVID-19 pandemic in France. The great majority of the cases we observed and those reported in the literature share the following common features: -lesions were of sudden onset in young patients without a previous history of chilblains in most of them and they were not necessarily triggered by exposure to cold; -those young patients were otherwise asymptomatic or pauci-symptomatic and only a few had mild clinical signs compatible with COVID-19; -none of them had pneumonia or severe manifestations of COVID-19; -clinical signs of COVID-19 or contact with infected persons occurred a few days to one month before chilblains; -SARS-CoV-2 infection could be demonstrated by nasopharyngeal swab or by serology only in very limited number of patients. The occurrence of an unusual high number of new cases of chilblain a few weeks after the start of the COVID-19 epidemic in many countries is probably not coincidental. Chilblains are a prototypical sign of a few inherited disorders of innate immunity, characterized by a strong interferon signature and a severe microangiopathy, called the type I interferonopathies (6, 7) . I therefore hypothesize that in a few genetically predisposed individuals the contact with SARS-CoV-2 triggers a strong interferon response, of which chilblain are the cutaneous expression. In some of them, this strong interferon response probably allows the clearing of the virus without intervention of the adaptive immune system, explaining the lack of antibodies in the patients who were tested so far. If this hypothesis holds true, that would suggest the possibility of a natural resistance to SARS-CoV-2 infection in a few individuals. That would also mean that those naturally protected individuals will not develop antibodies and would fail serologic detection, which is important in view of the interpretation of epidemiologic studies based on seroprevalence.

Chilblains in children in the setting of COVID-19 pandemic

Chilblains are a common cutaneous finding during the COVID-19 pandemic: a retrospective nationwide study from France

Chilblains-like lesions in children following suspected Covid-19 infection

Chilblain-like lesions: a case series of 41 patients during the COVID-19 pandemic

Characterization of acute acro-ischemic lesions in non-hospitalized patients: a case series of 132 patients during the COVID-19 outbreak

Type I interferon-mediated monogenic autoinflammation: The type I interferonopathies, a conceptual overview

Type I interferonopathies in pediatric rheumatology

No conflict of interest "Conflict of interest statement" I have no conflict of interest that influenced this work.