Evaluation of Chilblains as a Manifestation of the COVID-19 Pandemic

Bilateral Chilblain-like Lesions of the Toes Characterized by Microvascular Remodeling in Adolescents During the COVID-19 Pandemic

IMPORTANCE

Chilblain-like lesions have been one of the most frequently described cutaneous manifestations during the COVID-19 pandemic. Their etiopathogenesis, including the role of SARS-CoV-2, remains elusive.

OBJECTIVE

To examine the association of chilblain-like lesions with SARS-CoV-2 infection.

DESIGN, SETTING, AND PARTICIPANTS

This prospective case series enrolled 17 adolescents who presented with chilblain-like lesions from April 1 to June 30, 2020, at a tertiary referral academic hospital in Italy.

MAIN OUTCOMES AND MEASURES

Macroscopic (clinical and dermoscopic) and microscopic (histopathologic) analysis contributed to a thorough understanding of the lesions. Nasopharyngeal swab, serologic testing, and in situ hybridization of the skin biopsy specimens were performed to test for SARS-CoV-2 infection. Laboratory tests explored signs of systemic inflammation or thrombophilia. Structural changes in peripheral microcirculation were investigated by capillaroscopy.

RESULTS

Of the 17 adolescents (9 [52.9%] male; median [interquartile range] age, 13.2 [12.5-14.3] years) enrolled during the first wave of the COVID-19 pandemic, 16 (94.1%) had bilaterally localized distal erythematous or cyanotic lesions. A triad of red dots (16 [100%]), white rosettes (11 [68.8%]), and white streaks (10 [62.5%]) characterized the dermoscopic picture. Histologic analysis revealed a remodeling of the dermal blood vessels with a lobular arrangement, wall thickening, and a mild perivascular lymphocytic infiltrate. SARS-CoV-2 infection was excluded by molecular and serologic testing. In situ hybridization did not highlight the viral genome in the lesions.

CONCLUSIONS AND RELEVANCE

This study delineated the clinical, histologic, and laboratory features of chilblain-like lesions that emerged during the COVID-19 pandemic, and its findings do not support their association with SARS-CoV-2 infection. The lesions occurred in otherwise healthy adolescents, had a long but benign course to self-resolution, and were characterized by a microvascular remodeling with perivascular lymphocytic infiltrate but no other signs of vasculitis. These results suggest that chilblain-like lesions do not imply a concomitant SARS-CoV-2 infection. Ongoing studies will help clarify the etiopathogenic mechanisms.

Systemic and organ-specific immune-related manifestations of COVID-19

Immune-related manifestations are increasingly recognized conditions in patients with COVID-19, with around 3,000 cases reported worldwide comprising more than 70 different systemic and organ-specific disorders. Although the inflammation caused by SARS-CoV-2 infection is predominantly centred on the respiratory system, some patients can develop an abnormal inflammatory reaction involving extrapulmonary tissues. The signs and symptoms associated with this excessive immune response are very diverse and can resemble some autoimmune or inflammatory diseases, with the clinical phenotype that is seemingly influenced by epidemiological factors such as age, sex or ethnicity. The severity of the manifestations is also very varied, ranging from benign and self-limiting features to life-threatening systemic syndromes. Little is known about the pathogenesis of these manifestations, and some tend to emerge within the first 2 weeks of SARS-CoV-2 infection, whereas others tend to appear in a late post-infectious stage or even in asymptomatic patients. As the body of evidence comprises predominantly case series and uncontrolled studies, diagnostic and therapeutic decision-making is unsurprisingly often based on the scarcely reported experience and expert opinion. Additional studies are required to learn about the mechanisms involved in the development of these manifestations and apply that knowledge to achieve early diagnosis and the most suitable therapy.

COVID-19 Toes and Other Skin Lesions During the Pandemic: Emerging Entities?

There is accumulating evidence to indicate an association between coronavirus infectious disease 2019 (COVID-19) and clusters of incident cutaneous eruptions. Of these, chilblains-like perniosis have received widespread medical and media attention. These typically affect the toes, and have been called "COVID-toes." Other acral lesions such as large bullae have also been reported. However, a definitive causal relationship with the severe acute respiratory syndrome coronavirus 2 has not yet been definitively proven, nor has a pathogenic mechanism been established. These episodes are self-limiting, but we need to know whether long-term sequelae exist.

Zoonotic coronavirus epidemics: Severe acute respiratory syndrome, Middle East respiratory syndrome, and coronavirus disease 2019

OBJECTIVE

To review the virology, immunology, epidemiology, clinical manifestations, and treatment of the following 3 major zoonotic coronavirus epidemics: severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and coronavirus disease 2019 (COVID-19).

DATA SOURCES

Published literature obtained through PubMed database searches and reports from national and international public health agencies.

STUDY SELECTIONS

Studies relevant to the basic science, epidemiology, clinical characteristics, and treatment of SARS, MERS, and COVID-19, with a focus on patients with asthma, allergy, and primary immunodeficiency.

RESULTS

Although SARS and MERS each caused less than a thousand deaths, COVID-19 has caused a worldwide pandemic with nearly 1 million deaths. Diagnosing COVID-19 relies on nucleic acid amplification tests, and infection has broad clinical manifestations that can affect almost every organ system. Asthma and atopy do not seem to predispose patients to COVID-19 infection, but their effects on COVID-19 clinical outcomes remain mixed and inconclusive. It is recommended that effective therapies, including inhaled corticosteroids and biologic therapy, be continued to maintain disease control. There are no reports of COVID-19 among patients with primary innate and T-cell deficiencies. The presentation of COVID-19 among patients with primary antibody deficiencies is variable, with some experiencing mild clinical courses, whereas others experiencing a fatal disease. The landscape of treatment for COVID-19 is rapidly evolving, with both antivirals and immunomodulators demonstrating efficacy.

CONCLUSION

Further data are needed to better understand the role of asthma, allergy, and primary immunodeficiency on COVID-19 infection and outcomes.

Pernio (Chilblains), SARS-CoV-2, and COVID Toes Unified Through Cutaneous and Systemic Mechanisms

Pernio or chilblains is characterized by erythema and swelling at acral sites (eg, toes and fingers), typically triggered by cold exposure. Clinical and histopathologic features of pernio are well described, but the pathogenesis is not entirely understood; vasospasm and a type I interferon (IFN-I) immune response are likely involved. During the coronavirus disease 2019 (COVID-19) pandemic, dermatologists have observed an increase in pernio-like acral eruptions. Direct causality of pernio due to COVID-19 has not been established in many cases because of inconsistent testing methods (often negative results) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, a form of COVID-19‒associated pernio (also called COVID toes) is probable because of increased occurrence, frequently in young patients with no cold exposure or a history of pernio, and reports of skin biopsies with positive SARS-CoV-2 immunohistochemistry. PubMed was searched between January 1, 2020, and December 31, 2020 for publications using the following keywords: pernio, chilblain, and acral COVID-19. On the basis of our review of the published literature, we speculate that several unifying cutaneous and systemic mechanisms may explain COVID-19‒associated pernio: (1) SARS-CoV-2 cell infection occurs through the cellular receptor angiotensin-converting enzyme 2 mediated by transmembrane protease serine 2, subsequently affecting the renin-angiotensin-aldosterone system with an increase in the vasoconstricting, pro-inflammatory, and prothrombotic angiotensin II pathway. (2) Severe acute respiratory syndrome coronavirus 2 cell infection triggers an immune response with robust IFN-I release in patients predisposed to COVID-19‒associated pernio. (3) Age and sex discrepancies correlated with COVID-19 severity and manifestations, including pernio as a sign of mild disease, are likely explained by age-related immune and vascular differences influenced by sex hormones and genetics, which affect susceptibility to viral cellular infection, the renin-angiotensin-aldosterone system balance, and the IFN-I response.

Idiopathic perniosis presenting as acral purpuric lesions: Clustering of cases before COVID-19 pandemic and their comparison with chilblain like lesions reported in the literature

Perniosis/chilblains are the acral inflammatory skin lesions developing in susceptible individuals as an abnormal reaction to cold. In the absence of a discernible cause, it is labeled as idiopathic perniosis (IP). With the ongoing COVID-19 pandemic, there was an upsurge of reports of chilblain like lesions (CLL) especially in young patients possibly implicated to the SARS-CoV-2 virus. Twelve clinically suspected and histopathologically confirmed cases of IP seen from November 2019 through February 2020 were retrospectively recruited. Clinical, dermoscopic, and histopathological characteristics of these were reviewed and compared with CLL reported in the literature. Mean age of patients was 26.58 ± 15.18 years with an equal male to female ratio. Characteristic histopathology findings were spongiosis (100%), dermal edema (100%), perivascular lymphocytic infiltrate (100%) with peri-eccrine accentuation (66.7%), keratinocyte necrosis (50%), focal basal vacuolar damage (58.3%), and lymphocytic vasculitis (58.3%). Significant dermoscopy findings were variable background color ranging from dull red and violaceous to copper red and brown orange, coiled vessels (44.4%) and orange-red structureless areas (63.9%). Lesions over palms and soles preferentially had white dots/clods and lines (38.9%). There appears no exclusive histopathological as well as dermoscopy features of CLL and IP, yet certain clues can be appreciated. Keratinocyte necrosis and severe dermal edema favors IP, whereas fibrin thrombi with involvement of both superficial and deep dermal vessels favor CLL. Dermoscopically presence of irregular, linear or branching vessels, red/purple dots and clods and gray brown reticule supports CLL while white dots/clods and lines supports IP.

Cutaneous manifestations in a series of 417 patients with SARS-CoV-2 infection: epidemiological and clinical correlates of chilblain like lesions

A variety of dermatological lesions have been described in COVID-19, although the prevalence and pathogenic relationship remain unclear particularly for chilblain-like lesions. Dermatological examination was performed in a prospective cohort of consecutive patients seen at the service for SARS-CoV-2 infection. Out of 417 patients with confirmed SARS-CoV-2 infection [median age 29.5 years (range 15-65); 62.5% males], dermatological lesions were detected in 7 (1.7%). Three patients had acral lesions; their age (range) was 15-29 years; all had a negative nasopharyngeal swab and developed IgG and/or IgM-specific antibodies; all presented none or mild symptoms. A fourth patient remained negative at repeated testing; mother, father and sister had a documented mild COVID-19. Non-acral lesions were observed in four older patients, with severe COVID-19. Chilblain-like lesions may be the sole manifestation of SARS-CoV-2 infection; their presence in asymptomatic school children and adolescents should be considered a potential signal of familial or community spread of the virus.

Autoimmune and Rheumatic Manifestations Associated With COVID-19 in Adults: An Updated Systematic Review

Background: Numerous cases of the coronavirus disease 2019 (COVID-19) with autoimmune and rheumatic manifestations have been reported. Despite the available reviews that summarized its autoimmune/rheumatic manifestations, a systematic approach is still lacking. Therefore, we conducted a comprehensive systematic review in order to give an overview upon these rare but clinically significant manifestations.

Methods: We performed a literature search of PubMed and EMBASE as of October 9, 2020. All articles relevant to either systemic or organ-specific autoimmune and rheumatic manifestations potentially associated with COVID-19 were collected. The reviewed literature were limited to adults ≥18 years.

Results: Although most of the existing evidence was based on case reports or case series without a long-term follow-up, a variety of autoimmune/rheumatic manifestations were associated with COVID-19. The manifestations that have a consistent association with COVID-19 include autoimmune cytopenia, cutaneous vasculitis, encephalitis, and Guillain-Barre syndrome. Such association is conflicting as regards to antiphospholipid syndrome, hemophagocytic lymphohistiocytosis, and myasthenia gravis.

Conclusion: Our systematic review indicated the potential of the COVID-19 virus to trigger a myriad of autoimmune and rheumatic manifestations, which should be considered amid global efforts to combat COVID-19.

Diagnostic value of cutaneous manifestation of SARS-CoV-2 infection

Background

One of the challenging aspects of SARS‐CoV‐2 infection is its diverse multisystemic disease presentation.

Objectives

To evaluate the diagnostic value of cutaneous manifestations of SARS‐CoV‐2 infection and investigate their duration and timing in relation to other COVID‐19 symptoms.

Methods

We used data from 336 847 UK users of the COVID Symptom Study app to assess the diagnostic value of body rash or an acral rash in SARS‐CoV‐2 infection, and data from an independent online survey of 11 544 respondents to investigate skin‐specific symptoms and collect their photographs.

Results

Using data from the app, we show significant association between skin rashes and a positive swab test result (odds ratio 1·67, 95% confidence interval 1·42–1·97). Strikingly, among the respondents of the independent online survey, we found that 17% of SARS‐CoV‐2‐positive cases reported skin rashes as the first presentation, and 21% as the only clinical sign of COVID‐19. Together with the British Association of Dermatologists, we have compiled a catalogue of images of the most common skin manifestations of COVID‐19 from 400 individuals (https://covidskinsigns.com), which we have made publicly available to assist clinicians in recognition of this early clinical feature of COVID‐19.

Conclusions

Skin rashes cluster with other COVID‐19 symptoms, are predictive of a positive swab test, and occur in a significant number of cases, either alone or before other classical symptoms. Recognizing rashes is important in identifying new and earlier cases of COVID‐19.

What is already known about this topic?

Several studies conducted in hospital settings reported that patients with COVID‐19 presented with unusual skin rashes, including urticarial rashes, vesicular lesions and, less frequently, chilblains in fingers or toes.

What does this study add?

We confirmed, in a community‐based setting that also includes milder forms of the disease, that the presence of a skin rash is predictive of SARS‐CoV‐2 infection.

We provide a website with photos of skin manifestations to help healthcare professionals in diagnosing COVID‐19.

Skin rashes should be taken into account to provide a quick COVID‐19 diagnosis to curb the spread of the disease.

Linked Comment: Naldi. Br J Dermatol 2021; 184:793–794.

Acral Changes in pediatric patients during COVID 19 pandemic: Registry report from the COVID 19 response task force of the society of pediatric dermatology (SPD) and pediatric dermatology research alliance (PeDRA)

BACKGROUND/OBJECTIVE

In spring 2020, high numbers of children presented with acral pernio-like skin rashes, concurrent with the coronavirus disease 2019 (COVID-19) pandemic. Understanding their clinical characteristics/ infection status may provide prognostic information and facilitate decisions about management.

METHODS

A pediatric-specific dermatology registry was created by the Pediatric Dermatology COVID-19 Response Task Force of the Society for Pediatric Dermatology (SPD) and Pediatric Dermatology Research Alliance (PeDRA) and was managed by Children's Hospital of Philadelphia using REDCap.

RESULTS

Data from 378 children 0-18 years entered into the registry between April 13 and July 17, 2020 were analyzed. Data were drawn from a standardized questionnaire completed by clinicians which asked for demographics, description of acral lesions, symptoms before and after acral changes, COVID-19 positive contacts, treatment, duration of skin changes, laboratory testing including SARS-CoV-2 PCR and antibody testing, as well as histopathology. 229 (60.6%) were male with mean age of 13.0 years (± 3.6 years). Six (1.6%) tested positive for SARS-CoV-2. Pedal lesions (often with pruritus and/or pain) were present in 96%. 30% (114/378) had COVID-19 symptoms during the 30 days prior to presentation. Most (69%) had no other symptoms and an uneventful course with complete recovery.

CONCLUSIONS AND RELEVANCE

Children with acral pernio-like changes were healthy and all recovered with no short-term sequelae. We believe these acral changes are not just a temporal epiphenomenon of shelter in place during the spring months of the first wave of the COVID-19 pandemic and may be a late phase reaction that needs further study.

SARS-CoV-2, COVID-19, skin and immunology - What do we know so far?

The pandemic condition coronavirus disease (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can take asymptomatic, mild, moderate, and severe courses. COVID-19 affects primarily the respiratory airways leading to dry cough, fever, myalgia, headache, fatigue, and diarrhea and can end up in interstitial pneumonia and severe respiratory failure. Reports about the manifestation of various skin lesions and lesions of the vascular system in some subgroups of SARS-CoV-2-positive patients as such features outside the respiratory sphere, are rapidly emerging. Vesicular, urticarial, and maculopapular eruptions and livedo, necrosis, and other vasculitis forms have been reported most frequently in association with SARS-CoV-2 infection. In order to update information gained, we provide a systematic overview of the skin lesions described in COVID-19 patients, discuss potential causative factors, and describe differential diagnostic evaluations. Moreover, we summarize current knowledge about immunologic, clinical, and histologic features of virus- and drug-induced lesions of the skin and changes to the vascular system in order to transfer this knowledge to potential mechanisms induced by SARS-CoV-2.

The Influence of Media Coverage and Governmental Policies on Google Queries Related to COVID-19 Cutaneous Symptoms: Infodemiology Study

Background

During COVID-19, studies have reported the appearance of internet searches for disease symptoms before their validation by the World Health Organization. This suggested that monitoring of these searches with tools including Google Trends may help monitor the pandemic itself. In Europe and North America, dermatologists reported an unexpected outbreak of cutaneous acral lesions (eg, chilblain-like lesions) in April 2020. However, external factors such as public communications may also hinder the use of Google Trends as an infodemiology tool.

Objective

The study aimed to assess the impact of media announcements and lockdown enforcement on internet searches related to cutaneous acral lesions during the COVID-19 outbreak in 2020.

Methods

Two searches on Google Trends, including daily relative search volumes for (1) “toe” or “chilblains” and (2) “coronavirus,” were performed from January 1 to May 16, 2020, with the United States, the United Kingdom, France, Italy, Spain, and Germany as the countries of choice. The ratio of interest over time in “chilblains” and “coronavirus” was plotted. To assess the impact of lockdown enforcement and media coverage on these internet searches, we performed an interrupted time-series analysis for each country.

Results

The ratio of interest over time in “chilblains” to “coronavirus” showed a constant upward trend. In France, Italy, and the United Kingdom, lockdown enforcement was associated with a significant slope change for “chilblain” searches with a variation coefficient of 1.06 (SE 0.42) (P=0.01), 1.04 (SE 0.28) (P<.01), and 1.21 (SE 0.44) (P=0.01), respectively. After media announcements, these ratios significantly increased in France, Spain, Italy, and the United States with variation coefficients of 18.95 (SE 5.77) (P=.001), 31.31 (SE 6.31) (P<.001), 14.57 (SE 6.33) (P=.02), and 11.24 (SE 4.93) (P=.02), respectively, followed by a significant downward trend in France (–1.82 [SE 0.45]), Spain (–1.10 [SE 0.38]), and Italy (–0.93 [SE 0.33]) (P<.001, P=0.004, and P<.001, respectively). The adjusted R² values were 0.311, 0.351, 0.325, and 0.305 for France, Spain, Italy, and the United States, respectively, suggesting an average correlation between time and the search volume; however, this correlation was weak for Germany and the United Kingdom.

Conclusions

To date, the association between chilblain-like lesions and COVID-19 remains controversial; however, our results indicate that Google queries of “chilblain” were highly influenced by media coverage and government policies, indicating that caution should be exercised when using Google Trends as a monitoring tool for emerging diseases.

Coronavirus disease-19: The multi-level, multi-faceted vasculopathy

BACKGROUND AND AIMS

The new coronavirus disease (COVID-19) is a systemic disease. Mounting evidence depict signs and symptoms involving multiple organs, most of which supported by pathological data. A plausible link to these manifestations is vascular and endothelial dysfunction/damage. However, much of the current knowledge relies on opinion and incipient evidence. We aim to objectively appraise current evidence on the association between COVID-19 and vascular disease, specifically endotheliitis and vasculitis.

METHODS

Two researchers independently entered the search terms COVID-19 OR SARS-CoV-2 AND vasculitis, endotheliitis OR endothelium in the following online platforms: MedRxiv and LitCovid (PubMed). The search period was set from November 1, 2019 to August 28, 2020. Manuscripts with unavailable full texts, not in English, mainly on pre-clinical data, presenting only study designs or not directly related to the topics of this review were excluded. Retrospective and prospective studies, especially longitudinal ones, were given priority to the purpose of this review. Since there was paucity of prospective controlled evidence, case reports/series were also considered.

RESULTS

A total of 318 manuscripts were initially found. Sixty-seven (21%) were excluded: 59 (18.5%) met exclusion criteria and 8 (2.5%) were duplicates. One hundred and forty-two manuscripts (44,6%) did not provide original data and were also excluded: 35 (11%) were comments, 108 (33.9%) reviews; 1 (0.3%) position paper. One hundred and seven (33.6%) studies were considered for the present scoping review: 81 (25,5%) case reports/series; 18 (5.7%) prospective; 8 (2.5%) retrospective. Viral inclusions in endothelial cells, mononuclear cell infiltrates in the intima of small vessels and markers of endothelial cell apoptosis were demonstrated. Specificities of COVID-19 may lead to diverse vascular manifestations in different levels of the vascular bed.

CONCLUSIONS

Evidence indicates that COVID-19 targets vasculature and endothelium. However, high quality data is still lacking and studies with prospective designs and appropriately matched controls are needed.

[Histopathological features due to the SARS-CoV-2]

The infection due to the SARS-CoV-2 leads lesions mainly observed at the respiratory tract level, but not exclusively. The analyses of these lesions benefited from different autopsy studies. Thus, these lesions were observed in different organs, tissues and cells. These observations allowed us to rapidly improve the knowledge of the pathophysiological mechanisms associated with this emergent infectious disease. The virus can be detected in formalin fixed paraffin embedded tissues using immunohistochemistry, in situ hybridization, molecular biology and/or electron microscopy approaches. However, many uncertainties are still present concerning the direct role of the SARS-CoV-2 on the different lesions observed in different organs, outside the lung, such as the heart, the brain, the liver, the gastrointestinal tract, the kidney and the skin. In this context, it is pivotal to keep going to increase the different tissue and cellular studies in the COVID-19 positive patients aiming to better understanding the consequences of this new infectious disease, notably considering different epidemiological and co-morbidities associated factors. This could participate to the development of new therapeutic strategies too. The purpose of this review is to describe the main histological and cellular lesions associated with the infection due to the SARS-CoV-2.

Associations between COVID-19 and skin conditions identified through epidemiology and genomic studies

Background

Coronavirus disease 2019 (COVID-19) is commonly associated with skin manifestations, and may also exacerbate existing skin diseases, yet the relationship between COVID-19 and skin diseases remains unclear.

Objective

By investigating this relationship through a multiomics approach, we sought to ascertain whether patients with skin conditions are more susceptible to COVID-19.

Methods

We conducted an epidemiological study and then compared gene expression across 9 different inflammatory skin conditions and severe acute respiratory syndrome coronavirus 2–infected bronchial epithelial cell lines, and then performed a genome-wide association study transdisease meta-analysis between COVID-19 susceptibility and 2 skin diseases (psoriasis and atopic dermatitis).

Results

Skin conditions, including psoriasis and atopic dermatitis, increase the risk of COVID-19 (odds ratio, 1.55; P = 1.4 × 10⁻⁹) but decrease the risk of mechanical ventilation (odds ratio, 0.22; P = 8.5 × 10⁻⁵). We observed significant overlap in gene expression between the infected normal bronchial epithelial cells and inflammatory skin diseases, such as psoriasis and atopic dermatitis. For genes that are commonly induced in both the severe acute respiratory syndrome coronavirus 2 infection and skin diseases, there are 4 S100 family members located in the epidermal differentiation complex, and we also identified the “IL-17 signaling pathway” (P = 4.9 × 10⁻⁷⁷) as one of the most significantly enriched pathways. Furthermore, a shared genome-wide significant locus in the epidermal differentiation complex was identified between psoriasis and severe acute respiratory syndrome coronavirus 2 infection, with the lead marker being a significant expression quantitative trait locus for S100A12 (P = 3.3 × 10⁻⁷).

Conclusions

Together our findings suggest association between inflammatory skin conditions and higher risk of COVID-19, but with less severe course, and highlight shared components involved in anti–COVID-19 immune response.

Pediatric COVID toes and fingers

The emergence of the coronavirus disease 2019 (COVID-19) worldwide pandemic has been associated with a new constellation of cutaneous features in children. Among the unusual dermatologic presentations are the so-called COVID toes, inflammatory nodules of the feet and toes, sometimes involving the hands and fingers. These lesions mimic acral pernio, the synonym being chilblains. Unlike adult patients with COVID toes, children are less likely to manifest symptomatic COVID-19. Although a few studies have found some linkage to COVID-19 through the serum IgA or IgG severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein, other studies have no demonstrable linkage suggesting that barefoot children in cold weather develop such lesions. It appears that the chilblain-like lesions related to the period of the COVID-19 pandemic may reflect a brisk immune response portending a good prognosis and perhaps some form of innate immunity. The possible need to screen for coagulopathy is unclear, but this has been suggested in one report. Until we fully understand the pattern of immune response to COVID-19, questions may persist as to how disease manifestations are linked to SARS-CoV-2 exposures.

Chilblain-Like Lesions during COVID-19 Pandemic: The State of the Art

SARS-CoV-2 infection has spread all over the world in the last year, causing millions of COVID-19 cases among humans with a large variability of symptoms and signs, including those on the skin. Among these, a contemporary cluster of chilblain-like lesions with no certain relationship with the infection has been reported. The aim of this paper is to delineate a profile of chilblain-like lesions and to establish the state-of-the-art knowledge about this new phenomenon.

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 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.

Clinicopathologic correlations of COVID-19-related cutaneous manifestations with special emphasis on histopathologic patterns

Skin is one of target organs affected by the novel coronavirus SARS-CoV-2, and in response to the current COVID-19 pandemic, a fast body of literature has emerged on related cutaneous manifestations. Current perspective is that the skin is not only a bystander of the general cytokines storm with thrombophilic multiorgan injury, but it is directly affected by the epithelial tropism of the virus, as confirmed by the detection of SARS-CoV-2 in endothelial cells and epithelial cells of epidermis and eccrine glands. In contrast with the abundance of epidemiologic and clinical reports, histopathologic characterization of skin manifestations is limited. Without an adequate clinicopathologic correlation, nosology of clinically similar conditions is confusing, and effective association with COVID-19 remains presumptive. Several patients with different types of skin lesions, including the most specific acral chilblains-like lesions, showed negative results at SARS-CoV-2 nasopharyngeal and serologic sampling. The aim of this review is to provide an overview of what has currently been reported worldwide, with a particular emphasis on microscopic patterns of the skin manifestations in patients exposed to or affected by COVID-19. Substantial breakthroughs may occur in the near future from more skin biopsies, improvement of immunohistochemistry studies, RNA detection of SARS-CoV-2 strain by real-time polymerase chain reaction-based assay, and electron microscopic studies.

COVID-19: The experience from Iran

The first cases of coronavirus disease 2019 (COVID-19) in Iran were detected on February 19, 2020. Soon the entire country was hit with the virus. Although dermatologists were not immediately the frontline health care workers, all aspects of their practice were drastically affected. Adapting to this unprecedented crisis required urgent appropriate responses. With preventive measures and conserving health care resources being the most essential priorities, dermatologists, as an integral part of the health system, needed to adapt their practices according to the latest guidelines. The spectrum of the challenges encompassed education, teledermatology, lasers, and other dermatologic procedures, as well as management of patients who were immunosuppressed or developed drug reactions and, most importantly, the newly revealed cutaneous signs of COVID-19. These challenges have paved the way for new horizons in dermatology.

SARS-CoV-2 spike protein is present in both endothelial and eccrine cells of a chilblain-like skin lesion

Data on SARS‐CoV‐2 detection in lesional skin is controversial.^1‐8 We report a PCR‐proven COVID‐19 patient with a chilblain‐like SARS‐CoV‐2 positive skin lesion. An 80‐year‐old woman presented to the emergency department at the End of March 2020. She reported an onset of fever (38.4 C°) several days before admission, along with cough and shortness of breath. RT‐PCR from a nasopharyngeal swab was positive for SARS‐CoV‐2. An X‐ray showed evidence for right‐sided pneumonic infiltrates.

Six months into the pandemic. A review of skin manifestations in SARS-CoV-2 infection

During the COVID‐19 pandemic, various cutaneous manifestations have been described as associated with SARS‐CoV2 infection. It is debated if skin lesions could represent a diagnostic or prognostic indicator. Specifically, it is unclear whether skin lesions may be used to perform an early diagnosis and/or to predict worse outcomes. In this review, we described the cutaneous signs so far reported as COVID‐19‐related and discussed their incidence, clinico‐pathological features, and diagnostic and prognostic value.

Type I Interferon Signature in Chilblain-Like Lesions Associated with the COVID-19 Pandemic

Contemporarily to the new SARS-CoV-2 mediated COVID-19 pandemic, a rise in patients with acral chilblain lesions has been described. They manifest late after mild disease or asymptomatic exposure to SARS-CoV-2. Their pathogenic evolution is currently unknown. In biopsies from three patients with acral partially ulcerating chilblain lesions that occurred associated to the COVID-19 pandemic, we analysed the expression of type I interferon induced proteins and signal transduction kinases. Histology demonstrated perivascular and periadnexal lymphohistiocytic infiltrates and endothelial dominated MxA-staining, as well as pJAK1 activation. Our findings demonstrate induction of the type I IFN pathway in lesional sections of COVID-19-associated chilblain-like lesions. This may indicate a local antiviral immune activation status associated with preceding exposure to SARS-CoV-2.

Skin Manifestations Associated with COVID-19: Current Knowledge and Future Perspectives

Background

Coronavirus disease-19 (COVID-19) is an ongoing global pandemic caused by the “severe acute respiratory syndrome coronavirus 2” (SARS-CoV-2), which was isolated for the first time in Wuhan (China) in December 2019. Common symptoms include fever, cough, fatigue, dyspnea and hypogeusia/hyposmia. Among extrapulmonary signs associated with COVID-19, dermatological manifestations have been increasingly reported in the last few months.

Summary

The polymorphic nature of COVID-19-associated cutaneous manifestations led our group to propose a classification, which distinguishes the following six main clinical patterns: (i) urticarial rash, (ii) confluent erythematous/maculopapular/morbilliform rash, (iii) papulovesicular exanthem, (iv) chilblain-like acral pattern, (v) livedo reticularis/racemosa-like pattern, (vi) purpuric “vasculitic” pattern. This review summarizes the current knowledge on COVID-19-associated cutaneous manifestations, focusing on clinical features and therapeutic management of each category and attempting to give an overview of the hypothesized pathophysiological mechanisms of these conditions.

Severe COVID-19, multisystem inflammatory syndrome in children, and Kawasaki disease: immunological mechanisms, clinical manifestations and management

Multisystem inflammatory syndrome (MIS-C) is a pediatric hyperinflammation disorder caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). It has now been reported from several countries the world over. Some of the clinical manifestations of MIS-C mimic Kawasaki disease (KD) shock syndrome. MIS-C develops 4–6 weeks following SARS-CoV-2 infection, and is presumably initiated by adaptive immune response. Though it has multisystem involvement, it is the cardiovascular manifestations that are most prominent. High titres of anti-SARS-CoV-2 antibodies are seen in these patients. As this is a new disease entity, its immunopathogenesis is not fully elucidated. Whether it has some overlap with KD is still unclear. Current treatment guidelines recommend use of intravenous immunoglobulin and high-dose corticosteroids as first-line treatment. Mortality rates of MIS-C are lower compared to adult forms of severe COVID-19 disease.

Skin manifestations of COVID-19 in children: Part 1

The current COVID‐19 pandemic is caused by the SARS‐CoV‐2 coronavirus. The initial recognized symptoms were respiratory, sometimes culminating in severe respiratory distress requiring ventilation, and causing death in a percentage of those infected. As time has passed, other symptoms have been recognized. The initial reports of cutaneous manifestations were from Italian dermatologists, probably because Italy was the first European country to be heavily affected by the pandemic. The overall clinical presentation, course and outcome of SARS‐CoV‐2 infection in children differ from those in adults as do the cutaneous manifestations of childhood. In this review, we summarize the current knowledge on the cutaneous manifestations of COVID‐19 in children after thorough and critical review of articles published in the literature and from the personal experience of a large panel of paediatric dermatologists in Europe. In Part 1, we discuss one of the first and most widespread cutaneous manifestation of COVID‐19, chilblain‐like lesions. In Part 2, we review other manifestations, including erythema multiforme, urticaria and Kawasaki disease‐like inflammatory multisystemic syndrome, while in Part 3, we discuss the histological findings of COVID‐19 manifestations, and the testing and management of infected children, for both COVID‐19 and any other pre‐existing conditions.

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Cutaneous manifestations of COVID-19 in children (and adults): A virus that does not discriminate

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a beta coronavirus with a characteristic S-glycoprotein spike on the cell surface. Initial reports did not include cutaneous manifestations as a feature of COVID-19; however, there is a growing repertoire of reports demonstrating an array of dermatologic manifestations on the skin in children and adults. Dermatologic afflictions have been summarized into different categories several times, with the most recent analysis identifying six clinical patterns: urticaria, maculopapular-morbilliform eruption, papulovesicular exanthem, chilblain-like acral pattern, livedo reticularis-livedo racemosa pattern, and purpuric vasculitic pattern. In children, the dermatologic features appear to occur before or concomitantly with other COVID-19 manifestations. Dermatologists play a key role in diagnosing patients with COVID-19 who may present for the first time unwittingly exhibiting early signs of COVID-19. We have reviewed the current evidence on the dermatologic impact of COVID-19 in both the adult and pediatric populations.

Discordant anti-SARS-CoV-2 spike protein and RNA staining in cutaneous perniotic lesions suggests endothelial deposition of cleaved spike protein

BACKGROUND

Prior studies have shown the presence of immunohistochemical staining for the SARS-CoV-2 spike protein (SP) in endothelial cells and eccrine epithelium of acral perniosis classified as "COVID toes." Yet, other studies have been unable to detect SARS-CoV-2 RNA in skin biopsies of "COVID toes" by reverse-transcriptase polymerase chain reaction testing.

OBJECTIVE

In order to address these apparently conflicting findings, we compared detection of SARS-CoV-2 SP, through RNA in situ hybridization (ISH) vs immunohistochemistry (IHC), in skin biopsies of acral perniotic lesions presenting during the COVID-19 pandemic.

RESULTS

Three of six cases showed positive immunohistochemical labeling of endothelial cells, with one of three cases with sufficient depth also having labeling of eccrine glands, using an anti-SP SARS-CoV-2 antibody. These three cases positive with IHC were negative for SP by RNA ISH.

CONCLUSION

While the gold standard for detection of SARS-CoV-2 in tissue sections has yet to be determined, the detection of SARS-CoV-2 SP alone without spike RNA suggests that cleaved SP may be present in cutaneous endothelial cells and eccrine epithelium, providing a potential pathogenetic mechanism of COVID-19 endotheliitis.

Chilblains and COVID-19: why SARS-CoV-2 endothelial infection is questioned

Linked Article: Colmenero et al. Br J Dermatol 2020; 183:729–737.

Do we have serological evidences that chilblain-like lesions are related to SARS-CoV-2? A review of the literature

The outbreak of chilblain‐like lesions (CLL) coincidentally to the COVID‐19 pandemic is a topic of great concern. SARS‐CoV‐2 was initially hypothesized as the etiologic agent of CLL, but, since nasopharyngeal swabs seldom resulted positive, dermatologists' attention focused on the search for specific SARS‐CoV‐2 antibodies. Many papers were published contemporarily on this topic, reporting limited case series. We reviewed the English literature up to the first July 2020 and, excluding single case reports, we considered 13 studies that serologically investigated 220 patients. The presence of specific antibodies was detected in 18 subjects (8.2%): isolated IgA were found in 6 patients, IgA and IgG in 1, isolated IgG in 5, and IgM in 2. In 4 patients, isotypes were not specified. Our review demonstrated a high prevalence of negative serological results in CLL: antibodies were observed only in a few patients, that are even less excluding those with positive IgA, not clearly involved in the pathogenesis of the disease. In conclusion, although it is still uncertain whether CLL are related to SARS‐CoV‐2 infection, patients affected by CLL seem not to be prone to shedding the virus, hence, if they are asymptomatic, we can reassure them, thus avoiding hospital referral.

Perniosis during the COVID-19 pandemic: Negative anti-SARS-CoV-2 immunohistochemistry in six patients and comparison to perniosis before the emergence of SARS-CoV-2

BACKGROUND

Acral inflammatory lesions that have some resemblance to idiopathic or autoimmune-associated perniosis (chilblains) have been described in multiple countries during the COVID-19 pandemic.

METHODS

We examined histopathologic findings in six consecutive such cases from five patients received in mid-May to mid-June of 2020, evaluating immunohistochemical staining for the SARS-CoV-2 nucleocapsid protein. We compared these six cases to eight cases diagnosed as perniosis between January and June of 2019.

RESULTS

Five of six lesions with perniosis-like histopathology during the COVID-19 pandemic had distinctive tight cuffing of lymphocytes; intravascular material was present in one case. SARS-CoV-2 immunohistochemical staining using an antibody directed at the nucleocapsid protein was negative in all six cases. Only one of eight specimens with microscopic findings of perniosis received prior to the COVID-19 pandemic had tightly cuffed perivascular lymphocytes, and none had obvious intravascular occlusion.

CONCLUSIONS

A tightly cuffed pattern of perivascular lymphocytes is a feature of perniosis during the COVID-19 pandemic. The absence of SARS-CoV-2 nucleocapsid protein in these cases suggests against the virus being directly present in these lesions.

Chilblains in COVID-19 Infection

COVID-19 has quickly become a worldwide pandemic and is well-known for its pulmonary complications. Dermatologic manifestations such as chilblain-like lesions have been recently described, but it is unclear if they are truly secondary to the infection or not. Here we describe a young patient who developed chilblain-like eruptions on his toes, likely secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We discuss the literature that supports the hypothesis that these are in fact secondary to the infection, as well as provide insight into the pathology of these lesions.

Acral lesions in a pediatric population during the COVID-19 pandemic: a case series of 36 patients from a single hospital in Spain

BACKGROUND

To describe the cutaneous acral findings in a pediatric population noticed during this pandemic.

METHODS

A retrospective descriptive study was performed collecting data on 36 patients under 14 years old, presenting suspicious acral skin manifestations for coronavirus disease 2019 (COVID-19).

RESULTS

Patients were mostly male (63.8%). The mean age was 11.11 years. 66.67% of patients showed erythematous papules, and 44.44% purpuric macules. Feet were affected in 97.22% of patients and hands in 5.55%. Lesions were asymptomatic in 50% of patients. 30.55% of patients showed extracutaneous findings, preceding skin lesions in 12.62 days. Seven patients underwent specific severe acute coronavirus 2 (SARS-CoV-2) testing; all of these patients tested negative.

CONCLUSIONS

The association between these symptoms and SARS-CoV-2 remains unclear. We recommend using these manifestations as a sign of SARS-CoV-2 infection in children. This could lead to the examination of asymptomatic and mildly symptomatic children so that contagions may be avoided.