key: cord-0707297-nqjuee9t
authors: Maanaoui, S.; Salez, F.; Carpentier, O.
title: Recurrence of chilblains during a second contact with SARS‐CoV‐2: a case report
date: 2021-04-28
journal: Br J Dermatol
DOI: 10.1111/bjd.20070
sha: 23dac5e107484c2fa2297e8d2c7d205e0cf548fb
doc_id: 707297
cord_uid: nqjuee9t

Chilblains are among the most prevalent skin manifestations of Corona-VIrus Disease-19 (COVID-19) (1). However, the clinical presentation is atypical because most patients do not have a history of long cold exposure or of chilblains. These chilblains occur mostly in young adults with no or few COVID-19 symptoms and who are negative for SARS-CoV-2 in reverse transcription polymerase chain reaction (RT-PCR) and/or serological tests (1).

location for a skin biopsy. The lesions lasted at least 3 months. Based on the sequence of events, we diagnosed the recurrence of chilblains following contact with a SARS-CoV-2-positive close relative.

In the literature, an electron microscopy study found COVID-19 particles in the cytoplasm of endothelial cells in skin biopsies of patients who had chilblains and whose nasopharyngeal and oropharyngeal swabs were negative in a SARS-CoV-2 PCR test. 5 COVID-19 chilblains might results from the intense production of IFN-1, as seen in interferonopathies like lupus erythematosus. 6 The study of Battesti and Descamps highlighted strong expression of the gene coding for the IFN-induced Mx protein in skin biopsies from patients with chilblains. 4 The Mx protein sequesters viral factors required for viral replication. 6 Furthermore, an IFN-induced transmembrane protein may inhibit coronavirus replication. This could explain why PCR tests are mostly negative in patients with suspected COVID-19 chilblains. 4 Battesti and Descamps reported that patients with moderately severe COVID-19 had high circulating levels of IFN-1. 4 We hypothesize that in young adults with efficient innate immune responses, the IFN-1 pathway inhibits the replication of SARS-CoV-2 and dampens the symptoms of COVID-19. In parallel, activation of the IFN-1 pathway might lead to manifestations that have been already described in interferonopathies like lupus (i.e. chilblains). The inhibition of viral replication might explain the negative RT-PCR and serological test results in the present case.

To conclude, we report on a case of recurrent chilblains, the appearances of which coincided with the epidemic peaks in France and contact with a SARS-CoV-2-positive close relative. Our observation reinforces the hypothesis of a causal relationship between SARS-CoV-2 infection and chilblains. It also raises the question of whether this manifestation is likely to occur or recur during contact with SARS-CoV-2 components (e.g. during a mass vaccination campaign).

S. Maanaoui iD , 1 F. Salez 2 and O. Carpentier 1

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

Most chilblains observed during the COVID-19 outbreak occur in patients who are negative for COVID-19 on polymerase chain reaction and serology testing

Evaluation of chilblains as a manifestation of the COVID-19 pandemic

Negative tests for SARS-CoV-2 infection do not rule out its responsibility for chilblains

SARS-CoV-2 endothelial infection causes COVID-19 chilblains: histopathological, immunohistochemical and ultrastructural study of seven paediatric cases

Funding sources: none

Conflicts of interest: The authors declare they have no conflicts of interest