COVID toes: where do we stand with the current evidence?

Background: Numerous of cases of chilblains have been observed, mainly in young subjects with no or mild symptoms compatible with COVID-19. The pathophysiology of these lesions is still widely debated and an association with SARS-CoV-2 infection remains unconfirmed. Objectives: This paper focus on t...

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Main Authors: Marie Baeck, Anne Herman
Format: Article
Language:English
Published: Elsevier 2021-01-01
Series:International Journal of Infectious Diseases
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S1201971220322256
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author Marie Baeck
Anne Herman
author_facet Marie Baeck
Anne Herman
author_sort Marie Baeck
collection DOAJ
description Background: Numerous of cases of chilblains have been observed, mainly in young subjects with no or mild symptoms compatible with COVID-19. The pathophysiology of these lesions is still widely debated and an association with SARS-CoV-2 infection remains unconfirmed. Objectives: This paper focus on the unresolved issues about these COVID toes and in particular whether or not they are associated with COVID-19. Arguments: The temporal link between the outbreak of chilblains and the COVID-19 pandemic is a first suggests a link between the two events.Positive anti-SARS-CoV/SARS-CoV-2 immunostaining on skin biopsy of chilblains seem to confirm the presence of the virus in the lesions, but lack specificity and must be interpreted with caution.Conversely, RT-PCR and anti-SARS-CoV-2 serology were negative in the majority of patients with chilblains. Therefore, SARS-CoV-2 infection can be excluded, with relative certainty, even after accounting for possible lower immunization in mild/asymptomatic patients and for some differences in sensitivity/specificity between the tests used.Some authors hypothesize that chilblains could be the cutaneous expression of a strong type I interferon (IFN-I) response. High production of IFN-I is suggested to be associated with early viral control and may suppress antibody response. However, the absence of other cutaneous or extracutaneous symptoms as observed in other interferonopathies raises unanswered questions.To date, a direct link between chilblains and COVID-19 still seems impossible to confirm. A more indirect association due to lifestyle changes induced by lockdown is a possible explanation. Improvement of chilblains when protective measures were adopted and after lifting of lockdown, support this hypothesis. Conclusion: Conflicting current evidence highlights the need for systematic and repeated testing of larger numbers of patients and the need for valid follow-up data that take into consideration epidemic curves and evolution of lockdown measures.
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spelling doaj.art-4b990f971f19471e93b70796f1646d842022-12-21T21:56:52ZengElsevierInternational Journal of Infectious Diseases1201-97122021-01-011025355COVID toes: where do we stand with the current evidence?Marie Baeck0Anne Herman1Corresponding author.; Department of Dermatology, Cliniques universitaires Saint-Luc, Université catholique de Louvain (UCLouvain), Avenue Hippocrate 10, 1200, Brussels, BelgiumDepartment of Dermatology, Cliniques universitaires Saint-Luc, Université catholique de Louvain (UCLouvain), Avenue Hippocrate 10, 1200, Brussels, BelgiumBackground: Numerous of cases of chilblains have been observed, mainly in young subjects with no or mild symptoms compatible with COVID-19. The pathophysiology of these lesions is still widely debated and an association with SARS-CoV-2 infection remains unconfirmed. Objectives: This paper focus on the unresolved issues about these COVID toes and in particular whether or not they are associated with COVID-19. Arguments: The temporal link between the outbreak of chilblains and the COVID-19 pandemic is a first suggests a link between the two events.Positive anti-SARS-CoV/SARS-CoV-2 immunostaining on skin biopsy of chilblains seem to confirm the presence of the virus in the lesions, but lack specificity and must be interpreted with caution.Conversely, RT-PCR and anti-SARS-CoV-2 serology were negative in the majority of patients with chilblains. Therefore, SARS-CoV-2 infection can be excluded, with relative certainty, even after accounting for possible lower immunization in mild/asymptomatic patients and for some differences in sensitivity/specificity between the tests used.Some authors hypothesize that chilblains could be the cutaneous expression of a strong type I interferon (IFN-I) response. High production of IFN-I is suggested to be associated with early viral control and may suppress antibody response. However, the absence of other cutaneous or extracutaneous symptoms as observed in other interferonopathies raises unanswered questions.To date, a direct link between chilblains and COVID-19 still seems impossible to confirm. A more indirect association due to lifestyle changes induced by lockdown is a possible explanation. Improvement of chilblains when protective measures were adopted and after lifting of lockdown, support this hypothesis. Conclusion: Conflicting current evidence highlights the need for systematic and repeated testing of larger numbers of patients and the need for valid follow-up data that take into consideration epidemic curves and evolution of lockdown measures.http://www.sciencedirect.com/science/article/pii/S1201971220322256COVID-19SARS-CoV-2chilblainsCOVID toesacral lesionsserology tests
spellingShingle Marie Baeck
Anne Herman
COVID toes: where do we stand with the current evidence?
International Journal of Infectious Diseases
COVID-19
SARS-CoV-2
chilblains
COVID toes
acral lesions
serology tests
title COVID toes: where do we stand with the current evidence?
title_full COVID toes: where do we stand with the current evidence?
title_fullStr COVID toes: where do we stand with the current evidence?
title_full_unstemmed COVID toes: where do we stand with the current evidence?
title_short COVID toes: where do we stand with the current evidence?
title_sort covid toes where do we stand with the current evidence
topic COVID-19
SARS-CoV-2
chilblains
COVID toes
acral lesions
serology tests
url http://www.sciencedirect.com/science/article/pii/S1201971220322256
work_keys_str_mv AT mariebaeck covidtoeswheredowestandwiththecurrentevidence
AT anneherman covidtoeswheredowestandwiththecurrentevidence