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

Defining the short-term and long-term skin manifestations of COVID-19: insights after more than three years of the pandemic

AIM

This review aimed to assess the impact of coronavirus disease 2019 (COVID-19) on skin health to establish a classification of the skin lesions that occur most frequently during the disease and whether a particular category of skin damage is more likely to occur both in the short term and in the long term.

METHODS

We conducted a literature search of the PubMed database. Ultimately, 109 articles were included in this review. The exact phrases∕syntax and connectors used for the database search∕query were as follows: "Coronavirus and skin", "COVID-19 and skin", "SARS-CoV-2 and skin", "Coronavirus cutaneous manifestations", "COVID-19 cutaneous manifestations", "SARS-CoV-2 cutaneous manifestations", "Coronavirus dermatology", "SARS-CoV-2 and dermatology", "COVID-19 and dermatology", "COVID-19 and skin eruption", "Coronavirus and skin rash", "COVID-19 and hair", "Coronavirus and hair", "Coronavirus and nails", "SARS-CoV-2 and hair", and "SARS-CoV-2 and nails". Only articles with abstracts referring strictly to cutaneous manifestations of COVID-19 were chosen. Articles without abstracts were not considered.

RESULTS

We established six of the most frequently reported clinical patterns associated with COVID-19 and their probability of occurring during COVID-19 disease evolution based on the current literature reports. We did not identify the particular types of skin lesions that are most prone to long-term persistence; most such cases are rare, and no conclusion can be drawn based on them.

CONCLUSIONS

Apart from classified COVID-19-related skin disorders, this pandemic has been a challenge for dermatologists and a wide range of cutaneous side effects related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) treatments have been reported. We are aware of other polymorphic clinical presentations, with novel data being reported periodically, but the pathophysiological mechanisms and evolution are largely unknown.

COVID-19 cutaneous manifestations in children and adolescents: a systematic review

Objective:

The aim of this study was to evaluate the coronavirus disease 2019 (COVID-19) cutaneous manifestations described in pediatric patients and discuss their relevance for early diagnosis.

Data source:

The study consisted of a systematic review of original articles indexed in PubMed and Embase databases, as well as gray literature articles found through Google Scholar. A search strategy, based on PICO (Patient, Intervention, Comparison, Outcome) Tool, with the terms “child,” “infant,” “childhood,” “adolescents,” “teenagers,” “COVID-19,” “SARS-CoV-2,” and “skin manifestations,” was performed to optimize the findings. The study did not restrict any article regarding language.

Data synthesis:

Out of the 310 articles that initially met the inclusion criteria, 35 were selected for review, totalizing 369 patients. The most common COVID-19 cutaneous manifestations in children and adolescents were Chilblain-like lesions, presented in 67.5% of the cases, followed by erythema multiforme-like (31.7%) and varicella-like lesions (0.8%). The Chilblain-like lesions appeared 7.6 days (95%CI 7.4–7.8) after the viral infection and lasted for 17.5 days (95%CI 16.5–18.5), erythema multiforme-like lesions appeared in 9.5 days (95%CI 9–10) and lasted for 10.3 days (95%CI 9.1–11.5), and varicella-like lesions appeared in 12.3 days (95%CI 4–20.6) and lasted for 7 days.

Conclusions:

Knowledge of the different skin manifestations in children and adolescents with COVID-19 is essential for an early diagnosis and, consequently, the possibility of promptly care adoption as well as to interrupt the new coronavirus transmission chains in the current pandemic context.

Manifestações cutâneas da COVID-19 em crianças e adolescentes: uma revisão sistemática

RESUMO Objetivo: Avaliar as manifestações cutâneas da Doença de Coronavírus 2019 (COVID-19) descritas em pacientes pediátricos e discutir sua relevância para o diagnóstico precoce. Fontes de dados: O estudo consistiu em uma revisão sistemática de artigos originais indexados nas bases de dados PubMed e Embase, assim como na literatura cinzenta localizados via Google Scholar. Uma estratégia de busca, baseada na PICO (Patient, Intervention, Comparison, Outcome) Tool, com os termos “child”, “infant”, “childhood”, “adolescents”, “teenagers”, “COVID-19”, “SARS-CoV-2” e “skin manifestations” foi conduzida para otimizar os achados. Não houve restrições de idiomas. Síntese de dados: 35 dos 310 artigos que inicialmente cumpriram os critérios de inclusão foram selecionados para revisão, totalizando 369 pacientes. As manifestações cutâneas mais comuns de COVID-19 em crianças e adolescentes foram as lesões Chilblain-Like presentes em 67,5% dos casos, seguidas pelas lesões Eritema Multiforme-Like (31,7%) e Varicella-Like (0,8%). As lesões Chilblain-Like surgiram 7,6 dias (IC95% 7,4–7,8) após a infecção viral e tiveram duração de 17,5 dias (IC95% 16,5–18,5); as lesões Eritema Multiforme-Like surgiram em 9,5 dias (IC95% 9–10) e duraram 10,3 dias (IC95% 9,1–11,5) e as lesões Varicella-Like apareceram em 12,3 dias (IC95% 4–20,6) e duraram 7 dias. Conclusões: O conhecimento das diferentes manifestações cutâneas em crianças e adolescentes com COVID-19 é essencial para o diagnóstico precoce da doença, assim como possibilitar adoção de prontos cuidados e interromper cadeias de transmissão do novo coronavírus.

From Your Nose to Your Toes: A Review of Severe Acute Respiratory Syndrome Coronavirus 2 Pandemic‒Associated Pernio

Despite thousands of reported patients with pandemic-associated pernio, low rates of seroconversion and PCR positivity have defied causative linkage to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Pernio in uninfected children is associated with monogenic disorders of excessive IFN-1 immunity, whereas severe COVID-19 pneumonia can result from insufficient IFN-1. Moreover, SARS-CoV-2 spike protein and robust IFN-1 response are seen in the skin of patients with pandemic-associated pernio, suggesting an excessive innate immune skin response to SARS-CoV-2. Understanding the pathophysiology of this phenomenon may elucidate the host mechanisms that drive a resilient immune response to SARS-CoV-2 and could produce relevant therapeutic targets.

The skin as a critical window in unveiling the pathophysiologic principles of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiologic agent of coronavirus disease 2019 (COVID-19), is a single-stranded RNA virus whose sequence is known. COVID-19 is associated with a heterogeneous clinical phenotype ranging from asymptomatic to fatal disease. It appears that access to nasopharyngeal respiratory epithelia expressing angiotensin-converting enzyme (ACE) 2, the receptor for SARS-CoV-2, is followed by viral replication in the pulmonary alveolar septal capillary bed. We have demonstrated in earlier studies that incomplete viral particles, termed pseudovirions, dock to deep subcutaneous and other vascular beds, potentially contributing to the prothrombotic state and systemic complement activation that characterizes severe and critical COVID-19. A variety of skin eruptions have been described in the setting of SARS-CoV-2 infection and more recently, after COVID-19 vaccination. The vaccines deliver a laboratory-synthesized mRNA that encodes a protein that is identical to the spike glycoprotein of SARS-CoV-2, allowing the production of immunogenic spike glycoprotein that will then elicit T cell and B cell adaptive immune responses. In this contribution, we review an array of cutaneous manifestations of COVID-19 that provide an opportunity to study critical pathophysiologic mechanisms that underlie all clinical facets of COVID-19, ranging from asymptomatic/mild to severe and critical COVID-19. We classify cutaneous COVID-19 according to underlying pathophysiologic principles. In this regard we propose three main pathways: (1) complement mediated thrombotic vascular injury syndromes deploying the alternative and mannan binding lectin pathways and resulting in the elaboration of cytokines like interleukin 6 from endothelium in the setting of severe and critical COVID-19 and (2) the robust T cell and type I interferon-driven inflammatory and (3) humoral-driven immune complex mediated vasculitic cutaneous reactions observed with mild and moderate COVID-19. Presented are novel data on cutaneous vaccine reactions that manifest a clinical and morphologic parallel with similar eruptions observed in patients with mild and moderate COVID-19 and in some cases represent systemic eczematoid hypersensitivity reactions to a putative vaccine-based antigen versus unmasking subclinical hypersensitivity due to immune enhancing effects of the vaccine. Finally, we demonstrate for the first time the localization of human synthesized spike glycoprotein after the COVID-19 vaccine to the cutaneous and subcutaneous vasculature confirming the ability of SARS-CoV-2 spike glycoprotein to bind endothelium in the absence of intact virus.

Are the chilblain-like lesions observed during the COVID-19 pandemic due to severe acute respiratory syndrome coronavirus 2? Systematic review and meta-analysis

The expansion of the COVID‐19 pandemic has been accompanied by numerous reports of chilblain‐like lesions (CLL) in different countries; however, the pathogenesis of these lesions is still unclear. This systematic review and meta‐analysis aimed to assess the prevalence of COVID‐19 (diagnosed using PCR and/or serology) in patients with CLL. We undertook a literature search in PubMed, Embase, and Scopus (to 15 March 2021), including studies that reported on the number of patients with CLL with positive PCR and/or serology for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) or with a clinical suspicion of COVID‐19. Regardless of data heterogeneity, a random‐effects model was used to pool prevalence estimates. The meta‐analysis included 63 original studies, involving 2919 cases of CLL. A subgroup of these patients underwent diagnostic tests for COVID‐19 (PCR: n = 1154, 39.5%; serology: n = 943, 32.3%). The pooled prevalence of COVID‐19 in the overall sample and in the subgroup who were tested for COVID‐19 was, respectively: (i) positive PCR: 2.6% [95% confidence interval (CI) 1.9% to 3.4%] and 5.5% (95% CI, 3.7–7.7%); (ii) positive serology for SARS‐CoV‐2: 7.2% (95% CI, 4.7–10.2%) and 11.8% (95% CI, 7.9–16.3%); and (iii) positive PCR and/or serology, 15.2% (95% CI, 10.4–20.7%) and 7.5% (95% CI, 5.1–10.3%). Altogether, a small proportion of diagnostic tests for SARS‐CoV‐2, both PCR and serologies, show positive results in patients with CLL.

A clinicopathological description of COVID-19-induced chilblains (COVID-toes) correlated with a published literature review

Background

The abundance of publications of COVID‐19‐induced chilblains has resulted in a confusing situation.

Methods

This is a prospective single‐institution study from 15 March to 13 May 2020. Thirty‐two patients received PCR nasopharyngeal swabs. Of these, 28 patients had a thoracic CT‐scan, 31 patients had blood and urine examinations, 24 patients had skin biopsies including immunohistochemical and direct immunofluorescence studies, and four patients had electron microscopy.

Results

COVID‐19‐induced chilblains are clinically and histopathologically identical to chilblains from other causes. Although intravascular thrombi are sometimes observed, no patient had a systemic coagulopathy or severe clinical course. The exhaustive clinical, radiological, and laboratory work‐up in this study ruled‐out other primary and secondary causes. Electron microscopy revealed rare, probable viral particles whose core and spikes measured from 120 to 133 nm within endothelium and eccrine glands in two cases.

Conclusion

This study provides further clinicopathologic evidence of COVID‐19‐related chilblains. Negative PCR and antibody tests do not rule‐out infection. Chilblains represent a good prognosis, occurring later in the disease course. No systemic coagulopathy was identified in any patient. Patients presenting with acral lesions should be isolated, and chilblains should be distinguished from thrombotic lesions (livedo racemosa, retiform purpura, or ischemic acral necrosis).

Defense of COVID-19 by Human Organoids

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has created an immense menace to public health worldwide, exerting huge effects on global economic and political conditions. Understanding the biology and pathogenesis mechanisms of this novel virus, in large parts, relies on optimal physiological models that allow replication and propagation of SARS-CoV-2. Human organoids, derived from stem cells, are three-dimensional cell cultures that recapitulate the cellular organization, transcriptional and epigenetic signatures of their counterpart organs. Recent studies have indicated their great values as experimental virology platforms, making human organoid an ideal tool for investigating host-pathogen interactions. Here, we summarize research developments for SARS-CoV-2 infection of various human organoids involved in multiple systems, including lung, liver, brain, intestine, kidney and blood vessel organoids. These studies help us reveal the pathogenesis mechanism of COVID-19, and facilitate the development of effective vaccines and drugs as well as other therapeutic regimes.

Skin disorders associated with the COVID-19 pandemic: A review

Introduction

In December 2019, a new coronavirus has emerged out of China, the SARS‐CoV‐2 virus, causing a disease known as COVID‐19, which steadily has progressed into a pandemic. This coronavirus affects many organs, including the skin, whose manifestations are a consequence of the disease itself, as well as the preventative measures taken to avoid the infection. This paper reviews the cutaneous manifestations which currently have been encountered during this pandemic.

Methods

A search was conducted on PubMed, and all relevant articles were included.

Results

The results show the occurrence of many cutaneous findings, ranging from those related to the infection itself and to various dermatitides related to the use of personal protective equipment (PPE) utilized by healthcare workers while attending to infected patients.

Discussion

Recognizing these findings is important for the accurate diagnosis of those infected with COVID‐19 as well as the prompt treatment of the side effects caused by PPE that might further impair the effectiveness of healthcare workers.

Skin manifestations in COVID-19 patients, state of the art. A systematic review

INTRODUCTION

Since COVID-19 has become a pandemic, extensive literature has been produced. The commonest symptoms of COVID-19 disease are fever, cough, anosmia, and lymphocytopenia. However, other apparently less common clinical symptoms have been described, including skin lesions. We conducted a systematic review to evaluate skin involvement in COVID-19.

METHODS

The authors performed a systematic review of literature, in accordance with the Preferred Reporting Items for Systematic and Meta-Analysis (PRISMA). The search was reiterated until May 06, 2020.

RESULTS

Overall, 1593 patients (M/F ratio: 1 : 9) with suspect of COVID-19 were examined. The mean age was 37.8 (range 0-91) years. Among the analyzed patients, 84 (5.3%) were pediatrics (<18 years). Chilblains are very common among skin lesions and represent almost half of all skin lesions reported (46%); in 75% of patients with cutaneous manifestation, the latter presented before other typical clinical manifestation of COVID-19. Vasculitis or thrombosis was identified in almost 70% of patients who suffered from skin manifestations.

CONCLUSION

The present study highlights the importance of skin involvement in COVID-19. Limbs should be examined to eventually foresee the onset of further typical symptoms. Chilblains can be considered typical features. Studies with higher scientific evidence are required.

Im Zusammenhang mit COVID‐19‐Infektionen beschriebene Hautmanifestationen

Die Prävalenz aller kutanen Manifestationen, die direkt mit einer COVID‐19‐Infektion assoziiert sind, ist unbekannt. Allerdings steigt die Anzahl der entsprechenden Berichte schnell an und unser vorläufiges Wissen entwickelt sich rasch weiter. Die gemeldeten Hautmanifestationen lassen sich in zwei Gruppen einteilen: (1) Hautveränderungen, die unspezifisch auf eine mögliche infektiöse Erkrankung hinweisen, speziell makulopapulöses Exanthem, Urtikaria und Erythema multiforme, und (2) Hautveränderungen, die spezifischer auf eine COVID‐19‐Infektion hindeuten, insbesondere windpockenartige Läsionen, Livedo reticularis oder Frostbeulen‐artige Läsionen. Letztere scheinen mit thromboembolischen Ereignissen und vaskulären Veränderungen in Zusammenhang zu stehen.

Chilblain-Like Lesions (CLL) Associated With COVID-19 ("COVID Toes"): A Systematic Review

Reports of chilblain-like lesions (CLL) coinciding with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been described in the literature, but this phenomenon has not been critically summarized. The aim of this paper is to summarize reports of CLL coinciding with SARS-CoV-2 infection to clarify the prevalence, clinical relevance, and prognostic value of these lesions. A literature search was conducted using the Embase, Pubmed, and Scopus databases from December 2019 to June 16, 2020 using the search terms ("COVID-19" OR "coronavirus" OR "2019-nCoV" OR "SARS-CoV-2") AND ("chilblain-like" OR "COVID toes" OR "acral"). Papers that described skin changes in patients with suspected or confirmed COVID-19 were included. A total of 31 papers were summarized, representing 813 cases of CLL. Available data suggests an equal gender distribution, mean age of 21 years, and median age of 14 years. Mild extracutaneous symptoms were reported in 53% of cases and 47% were asymptomatic. CLL occurred an average of 16 days after extracutaneous symptoms. Patients with CLL were positive for SARS-CoV-2 in 15% of cases. Lesions were mainly described as asymptomatic and/or pruritic erythematous to violaceous acral macules and plaques. Partial or complete resolution occurred in 85% of cases in a mean of 13 days. The most common histologic findings were perivascular and perieccrine superficial and deep lymphocytic infiltrates. Although a causal relationship between CLL and SARS-CoV-2 has not been confirmed, the temporal association and 15% positive SARS-CoV-2 rate in affected individuals should not be ignored.

Histopathologic Features of Chilblainlike Lesions Developing in the Setting of the Coronavirus Disease 2019 (COVID-19) Pandemic

CONTEXT.—

During the coronavirus disease 2019 pandemic, several studies have described a distinctive cutaneous manifestation with a clinical picture resembling chilblains or chilblain lupus in young patients.

OBJECTIVE.—

To report the histopathologic description of a series of chilblainlike lesions appearing in the context of the severe acute respiratory syndrome coronavirus 2 epidemic.

DESIGN.—

The study included 13 patients with cutaneous acral lesions resembling chilblains occurring in the setting of suspected severe acute respiratory syndrome coronavirus 2 infection with available skin biopsy.

RESULTS.—

Two main histopathologic patterns were observed: a chilblainlike histopathologic pattern (10 of 13 cases; 77%) and a thrombotic vasculopathy pattern (3 of 13 cases; 23%). The chilblainlike histopathologic pattern featured a superficial and deep perivascular infiltrate of lymphocytes of varying intensity. This infiltrate was sometimes peri-eccrine and alterations of eccrine glands were present in most cases. Vacuolar alteration of the basal layer of the epidermis was found in a majority of patients. Lichenoid interface dermatitis was rarely present. The thrombotic vasculopathy pattern featured an absent or mild inflammatory infiltrate, multiple intraluminal fibrin thrombi, and ischemic epidermal necrosis. In both patterns, no true vasculitis was observed. No patient tested positive for severe acute respiratory syndrome coronavirus 2 by polymerase chain reaction, possibly because these lesions may represent late cutaneous manifestations of the disease or are associated with an early effective immune response.

CONCLUSIONS.—

The relationship of chilblainlike lesions to severe acute respiratory syndrome coronavirus 2 requires further investigations. Histopathologic features mimic chilblains, chilblain lupus, and, less frequently, a thrombotic vasculopathy. Response to viral infection might trigger diverse mechanisms leading to the 2 histopathologic patterns described.

Human and novel coronavirus infections in children: a review

Coronaviruses, seven of which are known to infect humans, can cause a spectrum of clinical presentations ranging from asymptomatic infection to severe illness and death. Four human coronaviruses (hCoVs)-229E, HKU1, NL63 and OC43-circulate globally, commonly infect children and typically cause mild upper respiratory tract infections. Three novel coronaviruses of zoonotic origin have emerged during the past two decades: severe acute respiratory syndrome coronavirus (SARS-CoV-1), Middle East respiratory syndrome coronavirus (MERS-CoV) and the recently discovered severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which is the cause of the ongoing coronavirus disease 2019 (COVID-19) pandemic. These novel coronaviruses are known to cause severe illness and death predominantly in older adults and those with underlying comorbidities. Consistent with what has been observed during the outbreaks of SARS and MERS, children with COVID-19 are more likely to be asymptomatic or to have mild-to-moderate illness, with few deaths reported in children globally thus far. Clinical symptoms and laboratory and radiological abnormalities in children have been similar to those reported in adults but are generally less severe. A rare multisystem inflammatory syndrome in children (MIS-C) which has resulted in critical illness and some deaths has recently been described. Clinical trials for therapeutics and vaccine development should include paediatric considerations. Children may play an important role in the transmission of infection and outbreak dynamics and could be a key target population for effective measures to control outbreaks. The unintended consequences of the unprecedented scale and duration of pandemic control measures for children and families around the world should be carefully examined.Abbreviations: 2019-nCoV, 2019 novel coronavirus; ADEM, acute demyelinating encephalomyelitis; AAP, American Academy of Pediatrics; ACE-2, angiotensin-converting enzyme 2; ARDS, acute respiratory distress syndrome; BCG, bacillus Calmette-Guérin; BNP, brain natriuretic peptide; CDC, Centers for Disease Control and Prevention; CRP, C-reactive protein; CSF, cerebrospinal fluid; COVID-19, coronavirus disease 2019; CT, computed tomography; CXR, chest X-ray; DOL, day of life; hCoV, human coronavirus; ICU, intensive care unit; IL, interleukin; IVIG, intravenous immunoglobulin; KD, Kawasaki disease; LDH, lactate dehydrogenase; MERS, Middle East respiratory syndrome; MERS-CoV, Middle East respiratory syndrome coronavirus; MEURI, monitored emergency use of unregistered and experimental interventions; MIS-C, multi-system inflammatory syndrome in children; PCR, polymerase chain reaction; PICU, paediatric intensive care unit; RNA, ribonucleic acid; RCT, randomised-controlled trial; RSV, respiratory syncytial virus; SARS, severe acute respiratory syndrome; SARS-CoV-1, severe acute respiratory syndrome coronavirus 1; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; TNF-alpha, tumour necrosis factor alpha; UK United Kingdom; UNICEF, United Nations Children's Fund; USA, United States of America; WHO, World Health Organization.

Skin manifestations reported in association with COVID-19 infection

The prevalence of all cutaneous manifestations directly associated with COVID-19 infection is unknown, but the number of reports is rapidly increasing and provisional knowledge is rapidly evolving. Skin manifestations reported can be classified into (1) manifestations unspecifically indicating possible infectious diseases, i.e. maculopapular exanthem, urticaria and erythema multiforme, and (2) manifestations more specifically indicating COVID-19 infection, i.e. varicella-like, livedo reticularis or chilblain-like eruptions. The latter appear to be associated with thrombovascular events and vascular pathologies.

COVID-19 and dermatology

Background/aim

Sars-CoV-2 virus infection (COVID-19) was observed in China in the last months of 2019. In the period following, this infection spread all over the world. In March 2020 the World Health Organization announced the existence of a pandemic. The aim of this manuscript is to investigate skin diseases associated with COVID-19 under three main headings: skin problems related to personal protective equipment and personal hygiene measures, skin findings observed in SARS-CoV-2 virus infections, and skin findings due to COVID-19 treatment agents.

Materials and methods

In PubMed, Google Scholar databases, skin lesions related to personal protective equipment and personal hygiene measures, skin findings observed in SARS-CoV-2 virus infections and skin findings due to COVID-19 treatment agents subjects are searched in detail.

Results

Pressure injury, contact dermatitis, itching, pressure urticaria, exacerbation of preexisting skin diseases, and new skin lesion occurrence/new skin disease occurrence may be due to personal protective equipment. Skin problems related to personal hygiene measures could include itching, dryness, and contact dermatitis. Skin findings may also be observed in SARS-CoV-2 virus infections. The incidence of skin lesions due to COVID-19 was reported to be between 0.2% and 29%. Many skin lesions including maculopapular, urticarial, vesicular, chilblain-like, thrombotic/ischemic, etc. are observed in COVID-19 patients. Some authors have stated that there is an absence of SARS-CoV-2 virus infection-specific skin findings. However, in asymptomatic or presymptomatic COVID-19 patients in particular, skin lesions can lead to the diagnosis of COVID-19. In addition, skin lesions may occur due to COVID-19 treatment agents.

Conclusion

Many skin lesions may appear as a result of COVID-19. Even in the absence of a COVID-19 diagnosis, skin findings should be evaluated carefully in this pandemic period.

The JANUS of chronic inflammatory and autoimmune diseases onset during COVID-19 - A systematic review of the literature

The diverse clinical manifestations of COVID-19 is emerging as a hallmark of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection. While the initial target of SARS-CoV-2 is the respiratory tract, it is becoming increasingly clear that there is a complex interaction between the virus and the immune system ranging from mild to controlling responses to exuberant and dysfunctional multi-tissue directed autoimmune responses. The immune system plays a dual role in COVID-19, being implicated in both the anti-viral response and in the acute progression of the disease, with a dysregulated response represented by the marked cytokine release syndrome, macrophage activation, and systemic hyperinflammation. It has been speculated that these immunological changes may induce the loss of tolerance and/or trigger chronic inflammation. In particular, molecular mimicry, bystander activation and epitope spreading are well-established proposed mechanisms to explain this correlation with the likely contribution of HLA alleles. We performed a systematic literature review to evaluate the COVID-19-related autoimmune/rheumatic disorders reported between January and September 2020. In particular, we investigated the cases of incident hematological autoimmune manifestations, connective tissue diseases, antiphospholipid syndrome/antibodies, vasculitis, Kawasaki-like syndromes, acute arthritis, autoimmune-like skin lesions, and neurologic autoimmune conditions such as Guillain–Barré syndrome. We screened 6263 articles and report herein the findings of 382 select reports which allow us to conclude that there are 2 faces of the immune response against SARS-CoV-2, that include a benign virus controlling immune response and a many faceted range of dysregulated multi-tissue and organ directed autoimmune responses that provides a major challenge in the management of this viral disease. The number of cases for each disease varied significantly while there were no reported cases of adult onset Still disease, systemic sclerosis, or inflammatory myositis.

•

The immune system plays a major role in the acute progression of COVID-19.

•

SARS-CoV-2 infection shares features with autoimmune diseases.

•

SARS-CoV-2 can induce Guillain-Barré syndrome, arthritis, chilblain-like lesions.

Anomalous asthma and chronic obstructive pulmonary disease Google Trends patterns during the COVID-19 pandemic

Background

An increase in online searches on health topics may either mirror epidemiological changes or reflect media coverage. In the context of COVID-19, this is particularly relevant, as COVID-19 symptoms may be mistaken for those of respiratory disease exacerbations. Therefore, we aimed to assess Internet search patterns on asthma and chronic obstructive pulmonary disease (COPD) in the context of COVID-19, as compared to searches on other chronic diseases.

Methods

We retrieved Google Trends (GTs) data on two respiratory (asthma and COPD) and three non-respiratory (diabetes, hypertension, and Crohn’s disease) chronic diseases over the past 5 years (up to May 31, 2020). For 54 countries, and for each disease, we built autoregressive integrated moving average (ARIMA) models to predict GTs for 2020 based on 2015–2019 search patterns. In addition, we estimated the proportion of searches in which COVID-19-related terms were used. To assess the potential impact of media coverage on online searches, we assessed whether weekly “asthma” GTs correlated with the number of Google News items on asthma.

Results

Over the past 5 years, worldwide search volumes for asthma and COPD reached their maximum values in March 2020. Such was not observed for diabetes, hypertension and Crohn’s disease. In 38 (70%) countries, GTs on asthma were higher in March 2020 than the respective maximum predicted values. This compares to 19 countries for COPD, 23 for hypertension, 11 for Crohn’s disease, and 9 for diabetes. Queries with COVID-19-related terms represented up to 47.8% of the monthly searches on asthma, and up to 21.3% of COPD searches. In most of the assessed countries, moderate-strong correlations were observed between “asthma” GTs and the number of news items on asthma.

Conclusions

During March 2020, there was a peak in searches on asthma and COPD, which was probably mostly driven by media coverage, as suggested by their simultaneity in several countries with different epidemiological situations.

Going viral: A brief history of Chilblain-like skin lesions ("COVID toes") amidst the COVID-19 pandemic

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the COVID-19 global pandemic, is notable for an expanding list of atypical manifestations including but not limited to coagulopathies, renal dysfunction, cardiac injury and a multisystem inflammatory syndrome in children. In addition, SARS-CoV-2 has been purportedly linked to multiple cutaneous manifestations, among them chilblain-like skin lesions, also known as "COVID toes." Driven in large part by social media, dermatologists around the world reported a dramatic increase in the frequency of chilblain-like diagnoses early in the COVID-19 pandemic, often in members of the same family. This phenomenon has been captured in a rapidly expanding medical literature. As of this writing, the chilblain-like presentation has been reported to occur predominantly in younger, minimally symptomatic patients and to emerge late in the COVID-19 disease course. Evidence of SARS-CoV-2 infection is not consistently found when these patients are evaluated by polymerase chain reaction. A robust antiviral immune response in young patients that induces microangiopathic changes has been posited as a mechanism. Herein we review the rapid evolution of the literature regarding chilblain-like skin lesions early in the COVID-19 global pandemic.

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

Background

Acral lesions, mainly chilblains, are the most frequently reported cutaneous lesions associated with COVID‐19. In more than 80% of patients tested, nasopharyngeal swabs were negative on reverse transcription polymerase chain reaction (RT‐PCR) for SARS‐CoV‐2 when performed, and serology was generally not performed.

Methods

A national survey was launched on 30 March 2020 by the French Society of Dermatology asking physicians to report cases of skin manifestations in patients with suspected or confirmed COVID‐19 by using a standardized questionnaire. We report the results for acral manifestations.

Results

We collected 311 cases of acral manifestations [58.5% women, median age 25.7 years (range 18–39)]. The most frequent clinical presentation (65%) was typical chilblains. In total, 93 cases (30%) showed clinical suspicion of COVID‐19, 67 (22%) had only less specific infectious symptoms and 151 (49%) had no clinical signs preceding or during the course of acral lesions. Histology of skin biopsies was consistent with chilblains. Overall, 12 patients showed significant immunological abnormalities. Of the 150 (48%) patients who were tested, 10 patients were positive. Seven of 121 (6%) RT‐PCR‐tested patients were positive for SARS‐CoV‐2, and five of 75 (7%) serology‐tested patients had IgG anti‐SARS‐CoV‐2. Tested/untested patients or those with/without confirmed COVID‐19 did not differ in age, sex, history or acral lesion clinical characteristics.

Conclusions

The results of this survey do not rule out that SARS‐CoV‐2 could be directly responsible for some cases of chilblains, but we found no evidence of SARS‐CoV‐2 infection in the large majority of patients with acral lesions during the COVID‐19 lockdown period in France.

What is already known about this topic?

About 1000 cases of acral lesions, mainly chilblains, were reported during the COVID‐19 outbreak.

Chilblains were reported to occur in young people within 2 weeks of infectious signs, which were mild when present.

Most cases did not have COVID‐19 confirmed by reverse transcription polymerase chain reaction (RT‐PCR), and few serology results were available.

What does this study add?

Among 311 patients with acral lesions, mainly chilblains, during the COVID‐19 lockdown period in France, the majority of patients tested had no evidence of SARS‐CoV‐2 infection.

Overall, 70 of 75 patients were seronegative for SARS‐Cov‐2 serology and 114 of 121 patients were negative for SARS‐CoV‐2 RT‐PCR.

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

Background

Chilblains (‘COVID toes’) are being seen with increasing frequency in children and young adults during the COVID‐19 pandemic. Detailed histopathological descriptions of COVID‐19 chilblains have not been reported, and causality of SARS‐CoV‐2 has not yet been established.

Objectives

To describe the histopathological features of COVID‐19 chilblains and to explore the presence of SARS‐CoV‐2 in the tissue.

Methods

We examined skin biopsies from seven paediatric patients presenting with chilblains during the COVID‐19 pandemic. Immunohistochemistry for SARS‐CoV‐2 was performed in all cases and electron microscopy in one.

Results

Histopathology showed variable degrees of lymphocytic vasculitis ranging from endothelial swelling and endotheliitis to fibrinoid necrosis and thrombosis. Purpura, superficial and deep perivascular lymphocytic inflammation with perieccrine accentuation, oedema, and mild vacuolar interface damage were also seen. SARS‐CoV‐2 immunohistochemistry was positive in endothelial cells and epithelial cells of eccrine glands. Coronavirus particles were found in the cytoplasm of endothelial cells on electron microscopy.

Conclusions

Although the clinical and histopathological features were similar to other forms of chilblains, the presence of viral particles in the endothelium and the histological evidence of vascular damage support a causal relation of the lesions with SARS‐CoV‐2. Endothelial damage induced by the virus could be the key mechanism in the pathogenesis of COVID‐19 chilblains and perhaps also in a group of patients severely affected by COVID‐19 presenting with features of microangiopathic damage.

What is already known about this topic?

Despite the high number of cases of chilblains seen during the COVID‐19 pandemic, a definite causative role for SARS‐CoV‐2 has not yet been proven.

Different pathogenetic hypotheses have been proposed, including coagulation anomalies, interferon release and external factors.

What does this study add?

The demonstration of SARS‐CoV‐2 in endothelial cells of skin biopsies by immunohistochemistry and electron microscopy confirms that these lesions are part of the spectrum of COVID‐19.

Virus‐induced vascular damage and secondary ischaemia could explain the pathophysiology of COVID‐19 chilblains.

Our findings support the hypothesis that widespread endothelial infection by SARS‐CoV‐2 could have a pathogenetic role in the severe forms of COVID‐19.

Linked Comment:  Wetter. Br J Dermatol 2020; 183:611.

A clinical, histopathological and laboratory study of 19 consecutive Italian paediatric patients with chilblain-like lesions: lights and shadows on the relationship with COVID-19 infection

Background

Acral chilblain‐like lesions are being increasingly reported during COVID‐19 pandemic. However, only few patients proved positivity for SARS‐CoV‐2 infection. The relationship between this skin manifestation and COVID‐19 infection has not been clarified yet.

Objective

To thoroughly characterize a prospective group of patients with chilblain‐like lesions and to investigate the possible relationship with SARS‐CoV‐2 infection.

Methods

Following informed consent, patients underwent (i) clinical evaluation, (ii) RT‐PCR and serology testing for SARS‐CoV‐2, (iii) digital videocapillaroscopy of finger and toe nailfolds, (iv) blood testing to screen for autoimmune diseases and coagulation anomalies, and (v) skin biopsy for histopathology, direct immunofluorescence and, in selected cases, electron microscopy.

Results

Nineteen patients, all adolescents (mean age: 14 years), were recruited. 11/19 (58%) of them and/or their cohabitants reported flu‐like symptoms one to two months prior to skin manifestation onset. Lesions were localized to toes and also heels and soles. Videocapillaroscopy showed pericapillary oedema, dilated and abnormal capillaries, and microhaemorrhages both in finger and toe in the majority of patients. Major pathological findings included epidermal basal layer vacuolation, papillary dermis oedema and erythrocyte extravasation, perivascular and perieccrine dermal lymphocytic infiltrate, and mucin deposition in the dermis and hypodermis; dermal vessel thrombi were observed in two cases. Blood examinations were normal. Nasopharyngeal swab for SARS‐CoV‐2 and IgG serology for SARS‐CoV‐2 nucleocapsid protein were negative. Importantly, IgA serology for S1 domain of SARS‐CoV‐2 spike protein was positive in 6 patients and borderline in 3.

Conclusions

Chilblain‐like lesions during COVID‐19 pandemic have specific epidemiologic, clinical, capillaroscopic and histopathological characteristics, which distinguish them from idiopathic perniosis. Though we could not formally prove SARS‐CoV‐2 infection in our patients, history data and the detection of anti‐SARS‐COV‐2 IgA strongly suggest a relationship between skin lesions and COVID‐19. Further investigations on the mechanisms of SARS‐CoV‐2 infection in children and pathogenesis of chilblain‐like lesions are warranted.