Acral cutaneous lesions in the time of COVID-19

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-associated chilblain-like acral lesions among children and adolescents: an Italian retrospective, multicenter study

BACKGROUND

Since the COVID-19 pandemic started, great interest has been given to this disease, especially to its possible clinical presentations. Besides classical respiratory symptoms, dermatological manifestations occur quite often among infected and non-infected patients, particularly in children. A prominent IFN-I response, that is generally higher in children compared to adults, may not only cause chilblain lesions, but it could also prevent infection and viral replication, thus justifying the negative swab results, as well as the absence of relevant systemic symptoms in positive cases. Indeed, reports have emerged describing chilblain-like acral lesions in children and adolescents with either proven or suspected infection.

METHODS

Patients aged from 1 to 18 years old were enrolled in this study from 23 Italian dermatological units and were observed for an overall period of 6 months. Clinical pictures were collected along with data on the location and duration of skin lesions, their association with concomitant local and systemic symptoms, presence of nail and/or mucosal involvement, as well as histological, laboratory and imaging findings.

RESULTS

One hundred thirty-seven patients were included, of whom 56.9% were females. Mean age was 11.97±3.66 years. The most commonly affected sites were the feet (77 patients, 56.2%). Lesions (48.5%) featured cyanosis, chilblains, blisters, ecchymosis, bullae, erythema, edema, and papules. Concomitant skin manifestations included maculo-papular rashes (30%), unspecified rashes (25%), vesicular rashes (20%), erythema multiforme (10%), urticaria (10%) and erythema with desquamation (5%). Forty-one patients (29.9%) reported pruritus as the main symptom associated with chilblains, and 56 out of 137 patients also reported systemic symptoms such as respiratory symptoms (33.9%), fever (28%), intestinal (27%), headache (5.5%), asthenia (3.5%), and joint pain (2%). Associated comorbid conditions were observed in 9 patients presenting with skin lesions. Nasopharyngeal swabs turned out positive in 11 patients (8%), whereas the remainder were either negative (101, 73%) or unspecified (25, 18%).

CONCLUSIONS

COVID-19 has been credited as the etiology of the recent increase in acro-ischemic lesions. The present study provides a description of pediatric cutaneous manifestations deemed to be potentially associated with COVID-19, revealing a possible association between acral cyanosis and nasopharyngeal swab positivity in children and teenagers. The identification and characterization of newly recognized patterns of skin involvement may aid physicians in diagnosing cases of asymptomatic or pauci-symptomatic COVID patients.

SARS-CoV-2 Vaccination and Chilblain-like Lesions: What Do We Know so Far?

INTRODUCTION

The coronavirus pandemic has caused massive damage to global health care and the economy. The vaccination program has been paced around the globe to return as soon as possible to pre-COVID time. Although all the vaccines have been approved after the rigorous clinical and safety trials, some adverse effects have surfaced and are being reported from different parts of the world. One such side effect is chilblain-like lesions following the COVID vaccination. Chilblain lesions, also known as pernio, are an inflammatory condition usually affecting the acral regions of the body. It is mostly reported from cold and damp areas and has multiple causes associated with it.

OBJECTIVE

This study aims to review the publicly available data and to provide concise and comprehensive information as well as evaluate the potential pathology, clinical approach, and management of CLL post-vaccination.

METHODS

An extensive literature search over PubMed, Cochrane library, Google Scholar, and Clinicaltrails. gov from inception till 5th October 2021, without any restriction of language was carried out. All the recruited articles were reviewed, and their bibliographies were also screened for any relevant information.

RESULTS

12 studies (10 case reports and 2 case series) were retrieved reporting the incidence of CLL post-vaccination. 8 studies reported incidence in female patients while 5 reported in males, with one study mentioning no gender. Moreover, most of them were either from Europe or the United States of America, except for two cases, reported from Turkey.

CONCLUSIONS

Although the overall incidence of Chilblains following COVID-19 vaccination is low, there is still a strong need to find out the exact mechanism behind this to redefine the safety and administration criteria of the vaccines and to formulate a proper management protocol.

Hygiene in der Dermatologie: SARS-CoV-2 und weitere Virus-Varianten

Die COVID-19-Pandemie hat weltweit erhebliche Beeinträchtigungen des Lebens und Arbeitens mit sich gebracht. Mit dem Beginn der Impfungen steigt die Hoffnung auf eine Kehrtwende. Dennoch sind COVID- und Intensivstationen in den Kliniken nach wie vor erheblich belastet. Häufig muss in den Kliniken aus Kapazitätsgründen auch dermatologisches Fachpersonal zur Betreuung von COVID-19-Patienten herangezogen werden. Dies führte dazu, dass im Verlauf der Pandemie dermatologische Manifestationen von COVID-19 erkannt und näher klassifiziert werden konnten. Differenzierte Hygienekonzepte, insbesondere die der Händehygiene, bringen jedoch ein weiteres, mit der Pandemie-assoziiertes dermatologisches Problem zum Vorschein: die Ausbildung von Handekzemen. Dies ist nicht nur auf medizinische Berufe beschränkt und zeigt daher eine mögliche übergeordnete Bedeutung der Dermatologie im Rahmen von zukünftigen Pandemiestrategien.

SARS-CoV-2 and Skin: New Insights and Perspectives

The SARS-CoV-2 pandemic has disrupted global health systems and brought the entire globe to its knees. Although born as a disease of the respiratory system, COVID-19 can affect different parts of the body, including the skin. Reports of ongoing skin manifestations of COVID-19 have gradually multiplied, pushing researchers to investigate the etiopathogenic mechanisms underlying these phenomena in more depth. In an attempt to investigate the possible association between SARS-CoV-2, ACE2, TMPRSS2 and skin manifestations, we performed immunohistochemical investigations of the ACE2 receptor and TMPRSS2 in nine skin samples from SARS-CoV-2-positive patients compared to a cohort of healthy controls. Furthermore, after consulting public databases regarding ACE2 mRNA expression in various cell populations resident in the skin, we conducted a literature review aimed at outlining the current state of this topic. We did not find statistically different immuno-expression of ACE2 and TMPRSS2 between the group of SARS-CoV-2-positive patients (nine skin biopsies) and the control group. Regarding ACE2, major immunolabeling was present in the epidermal keratinocytes and, rarely, in the fibroblasts and in the adenomeres of the eccrine sweat glands. Regarding the immune expression of TMPRSS2, we found no significant differences between the two groups, with a weak immune staining only in some skin cytotypes. From the review of the literature, we isolated 35 relevant articles according to the inclusion criteria adopted. ACE2 appears to be a target of SARS-CoV-2, although, other receptor molecules may potentially be implicated, such as TMPRSS2. Future studies with large cases and different molecular investigative methods are needed to further elucidate the mechanisms underlying the skin manifestations of SARS-CoV-2.

Manifestaciones dermatológicas asociadas a la gravedad de la infección por COVID-19. Estudio observacional transversal retrospectivo de 144 pacientes

Introducción

Material y métodos

Resultados

Conclusiones

Cutaneous Manifestations of COVID-19 in the Lower Limbs: A Narrative Review

In 2020, the World Health Organization declared the COVID-19 pandemic. This infectious pathology can be associated with different manifestations in different body systems, among which are dermatological lesions. The purpose of this work is to determine the most frequent dermatological signs, in the lower limbs, produced by SARS-CoV-2. To carry this out, a bibliographic search was performed in the following databases: PubMed, SciELO, ScienceDirect, Cochrane Database of Systematic Reviews, and the Google Scholar literature. The inclusion criteria were articles that included confirmed subjects or those with a clinical suspicion of COVID-19, written in the Spanish or English languages, and the results presented clinical manifestations in the lower extremities. Initially, 128 scientific documents were identified and, after reading the title and abstract, 18 articles were selected. The most frequent skin lesions on the lower limbs are acral lesions such as pernio erythema or ischemic lesions, maculopapular rash, petechiae, and erythematous plaques.

COVID-19 disease and autoimmune disorders: A mutual pathway

Coronavirus disease 2019 (COVID-19) is a real challenge for humanity with high morbidity and mortality. Despite being primarily a respiratory illness, COVID-19 can affect nearly every human body tissue, causing many diseases. After viral infection, the immune system can recognize the viral antigens presented by the immune cells. This immune response is usually controlled and terminated once the infection is aborted. Nevertheless, in some patients, the immune reaction becomes out of control with the development of autoimmune diseases. Several human tissue antigens showed a strong response with antibodies directed against many severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) proteins, such as SARS-CoV-2 S, N, and autoimmune target proteins. The immunogenic effects of SARS-CoV-2 are due to the sizeable viral RNA molecules with interrupted transcription increasing the pool of epitopes with increased chances of molecular mimicry and interaction with the host immune system, the overlap between some viral and human peptides, the viral induced-tissue damage, and the robust and complex binding between sACE-2 and SARS-CoV-2 S protein. Consequently, COVID-19 and its vaccine may trigger the development of many autoimmune diseases in a predisposed patient. This review discusses the mutual relation between COVID-19 and autoimmune diseases, their interactive effects on each other, the role of the COVID-19 vaccine in triggering autoimmune diseases, the factors affecting the severity of COVID-19 in patients suffering from autoimmune diseases, and the different ways to minimize the risk of COVID-19 in patients with autoimmune diseases.

Possible role of pannexin 1 channels and purinergic receptors in the pathogenesis and mechanism of action of SARS-CoV-2 and therapeutic potential of targeting them in COVID-19

Identifying signaling pathways and molecules involved in SARS-CoV-2 pathogenesis is pivotal for developing new effective therapeutic or preventive strategies for COVID-19. Pannexins (PANX) are ATP-release channels in the plasma membrane essential in many physiological and immune responses. Activation of pannexin channels and downstream purinergic receptors play dual roles in viral infection, either by facilitating viral replication and infection or inducing host antiviral defense. The current review provides a hypothesis demonstrating the possible contribution of the PANX1 channel and purinergic receptors in SARS-CoV-2 pathogenesis and mechanism of action. Moreover, we discuss whether targeting these signaling pathways may provide promising preventative therapies and treatments for patients with progressive COVID-19 resulting from excessive pro-inflammatory cytokines and chemokines production. Several inhibitors of this pathway have been developed for the treatment of other viral infections and pathological consequences. Specific PANX1 inhibitors could be potentially included as part of the COVID-19 treatment regimen if, in future, studies demonstrate the role of PANX1 in COVID-19 pathogenesis. Of note, any ATP therapeutic modulation for COVID-19 should be carefully designed and monitored because of the complex role of extracellular ATP in cellular physiology.

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.

Clinicopathologic features among different viral epidemic outbreaks involving the skin

The current coronavirus disease 2019 pandemic has exceeded any epidemiologic prevision, but increasing information suggests some analogies with the major viral outbreaks in the last century, and a general warning has been issued on the possibility that coinfections can make the differential diagnosis and treatment difficult, especially in tropical countries. Some reports have noted that the presence of high dengue antibodies can give a false-negative result when testing for severe acute respiratory syndrome coronavirus 2. Mucocutaneous manifestations are very frequent, with an apparent overlap among different pathogens. However, strong clinicopathologic correlation might provide some clues to address differentials. Waiting for laboratory and instrumental results, the timing and distribution of skin lesions is often pathognomonic. Histopathologic findings characterize certain reaction patterns and provide insights on pathogenetic mechanisms. Unfortunately, skin assessment, especially invasive examinations such as biopsy, takes a back seat in severely ill patients. A literature retrieval was performed to collect information from other epidemics to counteract what has become the most frightening disease of our time.

Demographic Characteristics of the Patients with Cutaneous Vasculitis Due to COVID-19 Infection

Background

Cutaneous manifestations of coronavirus disease 2019 (COVID-19) range from mild skin rashes to severe vasculitis. In the current study, we evaluated the demographic characteristics of the patients with cutaneous vasculitis following COVID-19 infection.

Materials and Methods

In the current study, we evaluated 799 hospitalised patients with COVID-19 infection for development of cutaneous vasculitis. Demographic and clinical characteristics of the patients were obtained using questionnaires and patients' records. Cutaneous vasculitis of the suspected patients were confirmed using skin biopsy and direct immunofluorescence.

Results

We detected 24 hospitalised cases with cutaneous vasculitis presenting with petechia, purpura, livedoretcularis and acrocyanosis. Our data showed a significant relationship between male sex, advanced age, C-reactive protein (CRP) level and presence of comorbidities with development of cutaneous vasculitis. In addition, we found a positive association between the severity of COVID-19 infection and occurrence of cutaneous vasculitis.

Conclusion

Our findings are suggestive that clinicians must be aware of cutaneous vasculitis risk as prognostic value in the patients with severe COVID-19 infection.

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.

Chilblains during lockdown are associated with household exposure to SARS-CoV-2: a multicentre case-control study

Objectives

During the COVID-19 pandemic, numerous cases of chilblains have been reported. However, in most cases, RT-PCR or serology did not confirm SARS-CoV-2 infection. Hypotheses have been raised about an interferon-mediated immunological response to SARS-CoV-2, leading to effective clearance of the SARS-CoV-2 without the involvement of humoral immunity. Our objective was to explore the association between chilblains and exposure to SARS-CoV-2.

Methods

In this multicentre case–control study, cases were the 102 individuals referred to five referral hospitals for chilblains occurring during the first lockdown (March to May 2020). Controls were recruited from healthy volunteers' files held by the same hospitals. All members of their households were included, resulting in 77 case households (262 individuals) and 74 control households (230 individuals). Household exposure to SARS-CoV-2 during the first lockdown was categorized as high, intermediate or low, using a pre-established algorithm based on individual data on symptoms, high-risk contacts, activities outside the home and RT-PCR testing. Participants were offered a SARS-CoV-2 serological test.

Results

After adjustment for age, the association between chilblains and viral exposure was estimated at OR 3.3, 95% CI (1.4–7.3) for an intermediate household exposure, and 6.9 (2.5–19.5) for a high household exposure to SARS-CoV-2. Out of 57 case households tested, six (11%) had positive serology for SARS-CoV-2, whereas all control households tested (n = 50) were seronegative (p = 0.03). The effect of potential misclassification on exposure has been assessed in a bias analysis.

Discussion

This case–control study demonstrates the association between chilblains occurring during the lockdown and household exposure to SARS-CoV-2.

Clinicopathologic features between different viral epidemic outbreaks involving the skin

The current coronavirus disease 2019 pandemic has exceeded any epidemiologic prevision, but increasing information suggests some analogies with the major viral outbreaks of the last century. A general warning has been issued on the possibility that coinfections can make differential diagnosis and treatment difficult, especially in tropical countries. Some reports have pointed out that the presence of high Dengue antibodies can give a false-negative result for severe acute respiratory syndrome coronavirus 2. Mucocutaneous manifestations are very frequent, with an apparent overlap among different pathogens. A strong clinicopathologic correlation, however, may provide some clues to address the differential. Waiting for laboratory and instrumental results, the timing and distribution of skin lesions is often pathognomonic. Histopathologic findings characterize certain reaction patterns and provide insights on pathogenetic mechanisms. Unfortunately, skin assessments, especially invasive exams such as biopsy, are less important in severely ill patients. A literature review was performed to collect information from other epidemics to counteract what has become the most frightening disease of our time.

Long-term Outcome of Chilblains Associated with SARS-CoV-2

Numerous cases of chilblains have been observed in the course if the COVID-19 pandemic. The aims of this study were to provide comprehensive follow-up data for patients reporting chilblains, and to determine the risk factors for incomplete recovery. Patients referred to 5 hospitals in France between March and May 2020 for chilblains were surveyed on December 2020. A teleconsultation was offered. Among 82 patients reporting chilblains, 27 (33%) reported complete recovery, 33 (40%) had recurrences of chilblains after their hands and feet had returned to normal, and 22 (27%) developed persistent acral manifestations, mostly acrocyanosis, with or without further recurrences of chilblains. Most recurrences of chilblains occurred during the following autumn and winter. A past history of chilblains was not associated with recurrences or persistent acral manifestations. Women had a significantly higher risk of developing recurrences or persistent acral manifestations (odds ratio 1.30; 95% confidence interval 1.06–1.59). In conclusion, two-thirds of patients reporting chilblains at the start of the COVID-19 pandemic experienced persistent or recurrent acral manifestations after a 10-month follow-up.

COVID-19-related skin manifestations: Update on therapy

An increasing body of evidence has been produced in a very limited period to improve the understanding of skin involvement in the current coronavirus 2019 disease pandemic, and how this novel disease affects the management of dermatologic patients. A little explored area is represented by the therapeutic approach adopted for the different skin manifestations associated with the infection. An overview of the current scenario is provided, through review of the English-language literature published until October 30, 2020, and comparison with the personal experience of the authors. As dermatologists, our primary aim is to support patients with the highest standard of care and relieve suffering, even with lesions not life-threatening. With asymptomatic COVID-19 patients, patient discomfort related to skin lesions should not be undervalued and intervention to accelerate healing should be provided. Consensus protocols are warranted to assess the best skin-targeted treatments in COVID-19 patients.

Infectious exanthemas in childhood

Most childhood exanthemas are harmless. However, recognizing serious diseases with life-threatening complications at an early stage is important for the timely initiation of adequate therapy. This requires knowledge of the specific patterns of the exanthema, obtained from the medical history and the clinic, including the patient's general condition and physical examination. In unclear cases, additional diagnostic measures are undertaken, such as blood tests and smears (cutaneous, mucocutaneous). Viruses are the most common cause of childhood exanthemas. New variants of infectious agents, improved diagnostics and stays in tropical and subtropical countries have expanded the spectrum of infectious exanthemas.

Erythema Multiforme and COVID-19: What Do We Know?

Background: Erythema multiforme (EM) is an acute cutaneous eruption often associated with infections and more rarely with drugs. This review aimed to evaluate the association between erythema multiforme and coronavirus disease 2019 (COVID-19). Methods: A systematic search of PubMed/MEDLINE, Scimago Scopus, and ISI/Web of Science was performed. Original articles, case series, or case reports were evaluated and selected. Results: Fourteen articles were selected, describing a total of 70 patients. EM is a cutaneous eruption rarely occurring in COVID-19 and is, in most cases, associated with a hypersensitivity reaction to the virus. In these cases, EM seems to affect patients younger than 30 years or older than 55 years. Infrequently, some drugs used in the management of COVID-19 may induce EM, especially hydroxychloroquine. The three groups of patients seem to have different clinical characteristics and courses. Conclusions: From these data, it is possible to preliminarily propose that EM or EM-like eruptions linked to COVID-19 might be divided into three types: the virus-related juvenile type (affecting patients <30-year-old), the virus-related older type (affecting patients >55 years), and the drug-induced type. The occurrence of a skin rash does not seem to be related to the severity and clinical course of COVID-19.

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).

[Skin lesions in children during the first wave of the SARS-CoV-2 pandemic]

BACKGROUND

Cutaneous manifestations have been included in COVID-19 patients' clinical spectrum. Our objective was to determine the association between skin lesions in children and SARS-CoV-2 infection, analyzing others possible infectious/autoimmune etiologies.

MATERIAL AND METHODS

Observational, multicenter, cross-sectional study, about children with skin manifestations from April to May 2020. The diagnosis of SARS-CoV-2 was performed by PCR in nasopharyngeal exudate and/or presence of antibodies by serology.

RESULTS

Sixty-two children were included, 9 (14.5%) presented positive antibodies to SARS-CoV-2, with no positive PCR to SARS-Cov-2 in those patients in whom it was made. Patients with positive serology to SARS-CoV-2 presented chilblains and/or vesicular-bullous skin lesions more frequently (66.7% vs. 24.5%, p=0.019). Generalized, urticarial and maculopapular rash was more common in patients with negative antibodies (37.7 vs. 0%, p=0.047), others pathogens were isolated in 41.5% of these patients. There were no significant differences in the positivity for autoantibodies between both groups.

CONCLUSION

In our study, the presence of chilblains-like and/or vesicular lesions were significantly related to SARS-CoV-2 previous contact.

Skin lesions in children during the first wave of the SARS-CoV-2 pandemic

BACKGROUND

Cutaneous manifestations have been included in COVID-19 patients' clinical spectrum. Our objective was to determine the association between skin lesions in children and SARS-CoV2 infection, analyzing others possible infectious/autoimmune etiologies.

MATERIAL AND METHODS

Observational, multicenter, cross-sectional study, about children with skin manifestations from April to May 2020. The diagnosis of SARS-CoV2 was performed by PCR in nasopharyngeal exudate and/or presence of antibodies by serology.

RESULTS

Sixty-two children were included, 9 (14.5%) presented positive antibodies to SARS-CoV-2, with no positive PCR to SARS-Cov-2 in those patients in whom it was made. Patients with positive serology to SARS-CoV-2 presented chilblains and/or vesicular-bullous skin lesions more frequently (66.7% vs. 24.5%, p = 0.019). Generalized, urticarial and maculopapular rash was more common in patients with negative antibodies (37.7 vs. 0%, p = 0.047), others pathogens were isolated in 41.5% of these patients. There were no significant differences in the positivity for autoantibodies between both groups.

CONCLUSION

In our study, the presence of chilblains-like and/or vesicular lesions were significantly related to SARS-CoV2 previous contact.

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.

Time of Onset of Selected Skin Lesions Associated with COVID-19: A Systematic Review

INTRODUCTION

Distinct skin lesions associated with coronavirus disease 2019 (COVID-19) have been described, but data regarding their time of onset during the COVID-19 course are scant. Our objective was to systematically review the studies reporting the time of onset of selected skin lesions with respect to the reported onset of the COVID-19 core symptoms.

METHODS

A comprehensive search of studies published before 21 January 2021 was performed on MEDLINE via PubMed database using a predefined strategy to identify relevant articles.

RESULTS

Out of 354 references, 87 were selected, reporting a total of 895 patients with skin lesions associated with COVID-19. The most frequent pattern was exanthema (n = 430, 48%), followed by vascular (n = 299, 33%), urticarial (n = 105, 12%) and others (n = 66, 7%). Skin lesions occurred more frequently in the first 4 weeks from the COVID-19 onset (n = 831, 92%), whereas prodromal or late lesions were rarer (n = 69, 8%). The urticarial and exanthema patterns were more frequent in the first 2 weeks. About the vascular pattern some differences were noted among its subtypes. Livedoid lesions occurred mainly in the first 2 weeks, while chilblain-like lesions between weeks 2 and 4. Purpuric/petechial lesions were equally distributed during the first 4 weeks. Several skin manifestations did not fall into the pattern classification, including erythema multiforme, generalized pruritus, Kawasaki disease and others.

CONCLUSION

The diversity in the time of onset of skin lesions as well as their polymorphic nature likely reflects the diversity of the pathogenetic underlying mechanisms.

PROSPERO DATABASE REGISTRATION NUMBER

CRD42021236331.

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.

A narrative review of coronavirus disease 2019 (COVID-19): clinical, epidemiological characteristics, and systemic manifestations

Coronavirus disease 2019 (COVID-19) is an emerging infectious disease which has had a rapid surge in cases and deaths since it is first documented in Wuhan, China, in December 2019. COVID-19 is caused by the Betacoronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 uses angiotensin-converting enzyme 2, which is highly expressed in the human lower respiratory tract but also in other tissues, as the cellular entry receptor. Thus, COVID-19 mainly affects the respiratory system but can cause damage to other body systems, including the cardiovascular, gastrointestinal, hepatobiliary, renal, and central nervous systems. We review the pathogenesis and clinical manifestations of the infection, focusing on our current understanding of the disease mechanisms and their translation to clinical outcomes, as well as adverse effects on different body systems. We also discuss the epidemiology pathogenesis, clinical, and multi-organ consequences, and highlight some of the research gaps regarding COVID-19.

A systematic review of the histopathologic survey on skin biopsies in patients with Corona Virus Disease 2019 (COVID-19) who developed virus or drug-related mucocutaneous manifestations

The mucocutaneous manifestations of Corona Virus Disease 2019 (COVID‐19) logically may reflect systemic visceral involvements. These findings are visible and easy to approach like biopsies for exact histopathologic evaluations. This systematic review was conducted to collect the mucocutaneous histopathologic data of COVID‐19 patients for future investigations and interpretations. The COVID‐19 dermatology resource of the Centre of Evidence‐Based Dermatology (CEBD) at the University of Nottingham, PubMed, Scopus, Google Scholar and Medscape was searched for relevant English articles published by June 3, 2020. This review included 31 articles, involving 459 patients. The common primary virus‐related mucocutaneous manifestations are easy to approach in the course of COVID‐19. The authors of this study supposed dermatopathological findings as the predictors of the nature of potential systemic involvements and outcomes of COVID‐19. Scrutinizing these findings can help with adopting more effective therapeutic and management strategies; nevertheless, this review found the severity and time of onset of symptoms not to be associated with the laboratory and histopathological findings. Deterioration of clinical conditions and laboratory tests was also not related to the histopathological findings. It is recommended that meta‐analyses be conducted in the future to detail on these data for having more comprehensive and better conclusion.

Clinical Manifestations of COVID-19 in the Feet: A Review of Reviews

There is a lack of scientific evidence about the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The clinical manifestations are not thoroughly understood; classically, the virus manifests itself at the pulmonary level but can manifest at other levels. To the best of our knowledge, systematic reviews and non-systematic reviews about COVID-19 symptoms in the feet have not been published. The aim of this review of reviews was to analyze and synthesize the published reviews on manifestations of COVID-19 at the foot level. Methods: a review of reviews was conducted; the eligibility criteria included studies published in English or Spanish, involving children and adults with COVID-19, and reporting foot manifestations. PubMed, SciELO, Science Direct, Cochrane Database of Systematic Review, and Google Scholar were analyzed. Two authors independently performed the screening and quality assessment of the studies with AMSTAR 1, and finally, nine reviews were analyzed (one systematic and eight narratives studies). The main clinical manifestations at the foot level in patients with COVID-19 were vascular (edema, exanthems, chilblains, ischemia, and distal necrosis), dermatological (vesicular, maculopapular, papulosquamous, urticarial skin breakouts, and recurrent herpes), and neurological (muscular weakness in lower limbs, paresis, areflexias, ataxia, and difficulty walking). Erythema pernio or "COVID toes" was shown as the most characteristic lesion of this disease, especially in asymptomatic children and young people, so this typical manifestation may be considered important in patients who are positive for COVID-19. This finding does not allow for strong conclusions due to the scarce literature and methodological quality in this regard. Future studies are necessary.

The Role of IL-36 in Infectious Diseases: Potential Target for COVID-19?

IL-36 is a member of the interleukin 1 cytokine family, which is currently experiencing a renaissance due to the growing understanding of its context-dependent roles and advances in our understanding of the inflammatory response. The immunological role of IL-36 has revealed its profound and indispensable functional roles in psoriasis, as well as in several inflammatory diseases, including inflammatory bowel disease (IBD), systemic lupus erythematosus, rheumatoid arthritis (RA) and cancer. More recently, an increasing body of evidence suggests that IL-36 plays a crucial role in viral, bacterial and fungal infections. There is a growing interest as to whether IL-36 contributes to host protective immune responses against infection as well as the potential implications of IL-36 for the development of new therapeutic strategies. In this review, we summarize the recent progress in understanding cellular expression, regulatory mechanisms and biological roles of IL-36 in infectious diseases, which suggest more specific strategies to maneuver IL-36 as a diagnostic or therapeutic target, especially in COVID-19.

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.

COVID-19: The Italian experience

Italy was among the world's earliest and most affected countries by coronavirus disease 2019 (COVID-19). We report the Italian experience with the pandemic. The dermatologic community immediately reduced any type of activities to 80% to 90% of outpatient consultations, both in public hospitals and in private offices. The Italian Society of Dermatology and Sexually Transmitted Diseases and the Italian Forensic Dermatologic Society supported the dermatologic community by reporting recommendations in newsletters (vademecum) regarding the routine management of dermatologic patients either in the hospital or private setting. We have provided an overview of the skin manifestations from the pandemic, including the consequences of the misuse of safety measures. We also have evaluated the recently developed research projects on patients treated with biologics for psoriasis, atopic dermatitis, and hidradenitis suppurativa, as well as on the registries regarding various skin diseases affected by COVID-19.

Cutaneous manifestations and dermatological sequelae of Covid-19 infection compared to those from other viruses

In the last few months, there have been numerous reports describing a variety of cutaneous signs associated with COVID-19. Clinicians from Italy were the first to describe the cutaneous manifestations of COVID-19, which were later observed in other parts of the globe. In some cases, cutaneous signs were the only manifestation of COVID-19 rather than the typical syndrome of fever and upper respiratory tract symptoms. However, there is considerable heterogeneity amongst the cutaneous signs described so far, which has been published extensively. Our aim is to summarise the latest studies that have reported the early and late cutaneous signs of COVID-19 and compare them to the most common established viral exanthems.

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.

Skin Manifestation of SARS-CoV-2: The Italian Experience

At the end of December 2019, a new coronavirus denominated Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) was identified in Wuhan, Hubei province, China. Less than three months later, the World Health Organization (WHO) declared coronavirus disease-19 (COVID-19) to be a global pandemic. Growing numbers of clinical, histopathological, and molecular findings were subsequently reported, among which a particular interest in skin manifestations during the course of the disease was evinced. Today, about one year after the development of the first major infectious foci in Italy, various large case series of patients with COVID-19-related skin manifestations have focused on skin specimens. However, few are supported by histopathological, immunohistochemical, and polymerase chain reaction (PCR) data on skin specimens. Here, we present nine cases of COVID-positive patients, confirmed by histological, immunophenotypical, and PCR findings, who underwent skin biopsy. A review of the literature in Italian cases with COVID-related skin manifestations is then provided.

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.

Cutaneous Manifestations in Patients With COVID-19: Clinical Characteristics and Possible Pathophysiologic Mechanisms

The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections soon led to a pandemic with serious health, economic, political, and cultural repercussions across the globe. The disease caused by SARS-CoV-2, coronavirus disease 2019 (COVID-19), is a multisystemic disease that requires a multidisciplinary approach involving specialists from all fields and levels of care. In this article, we review the literature on the diverse cutaneous manifestations associated with COVID-19. We also describe the pathophysiologic mechanisms proposed to date and their possible association with these manifestations. Finally, we propose a system for classifying the cutaneous manifestations of COVID-19 according to their underlying pathophysiologic mechanisms and prognosis.

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.

Cutaneous Manifestations Related to COVID-19 Immune Dysregulation in the Pediatric Age Group

Purpose of Review

At the juncture of the COVID-19 pandemic, the world is currently in an early phase of collecting clinical data and reports of its skin manifestations, and its pathophysiology is still highly conjectural. We reviewed cutaneous manifestations associated with COVID-19 in the pediatric age group.

Recent Findings

Children infected by SARS-CoV-2 usually develop milder respiratory symptoms, but cutaneous manifestations seem a little more prevalent than in adults. These skin features of infection by the coronavirus can be similar to those produced by other common viruses, but there are also reports of cases with more heterogeneous clinical pictures, which have made their classification difficult. To date, the more frequently reported skin variants featured in pediatric cases are purpuric (pseudo-chilblain, necrotic-acral ischemia, hemorrhagic macules, and/or cutaneous necrosis), morbilliform/maculopapular, erythema multiforme, urticarial, vesicular, Kawasaki-like, and miscellaneous (highly variable in both frequency and severity). Their pathophysiological mechanism is still elusive and is likely to be the result of the complex involvement of one or more mechanisms, like direct virus-induced skin damage, vasculitis-like reactions, and/or indirect injury as a consequence of a systemic inflammatory reaction.

Summary

In this review, we presented and discussed clinical cases as examples of different cutaneous responses reported in some children with SARS-CoV-2 infection, differential diagnosis considerations, and a preliminary conceptual approach to some of their probable associated pathologic mechanisms.

Spectrum of Clinicopathologic Findings in COVID-19-induced Skin Lesions: Demonstration of Direct Viral Infection of the Endothelial Cells

The novel coronavirus disease (COVID-19) is a rapidly spreading pandemic, secondary to severe acute respiratory syndrome coronavirus 2. The severity and the little knowledge that we have of the disease have made us focus mostly on the respiratory symptoms. As we bend the curve, other findings reported in association with COVID-19 become of importance for specialists to recognize. We describe the spectrum of clinicopathologic lesions in the skin that can be the only symptom or the first manifestation of COVID-19 and demonstrate the origin of the virus. We collected 25 patients with skin lesions in this context. We recognized 5 types of cutaneous manifestations including acute acroischemic or chilblain-like lesions (11), purpura palpable (2), exanthemas (9), urticarial eruptions (1), and other lesions (2) that might appear with more unspecific pictures. Chilblain-like lesions were the most common form of presentation, which tend to appear as self-healing, erythematous-necrotic plaques mostly on the feet, in young patients with no systemic symptoms associated. Importantly, we visualized viral particles with electron microscopy in 5 of 13 cases analyzed. In this study, we seek to draw a picture of the spectrum of clinicopathologic lesions that may appear in the skin in the context of COVID-19. Although apparently skin lesions are not correlated with disease severity, it may help in some cases to recognize and control the spread of the infection sooner.

Skin Manifestations in COVID-19 Patients: Are They Indicators for Disease Severity? A Systematic Review

Introduction: Until now, there are several reports on cutaneous manifestations in COVID-19 patients. However, the link between skin manifestations and the severity of the disease remains debatable. We conducted a systematic review to evaluate the temporal relationship between different types of skin lesions and the severity of COVID-19. Methods: A systematic search was conducted for relevant studies published between January and July 2020 using Pubmed/Medline, Embase, and Web of knowledge. The following keywords were used: "SARS-CoV-2" or "COVID-19" or "new coronavirus" or "Wuhan Coronavirus" or "coronavirus disease 2019" and "skin disease" or "skin manifestation" or "cutaneous manifestation." Results: Out of 381 articles, 47 meet the inclusion criteria and a total of 1,847 patients with confirmed COVID-19 were examined. The overall frequency of cutaneous manifestations in COVID-19 patients was 5.95%. The maculopapular rash was the main reported skin involvement (37.3%) commonly occurred in middle-aged females with intermediate severity of the disease. Forty-eight percentage of the patients had a mild, 32% a moderate, and 20% a severe COVID-19 disease. The mild disease was mainly correlated with chilblain-like and urticaria-like lesions and patients with vascular lesions experienced a more severe disease. Seventy-two percentage of patients with chilblain-like lesions improved without any medication. The overall mortality rate was 4.5%. Patients with vascular lesions had the highest mortality rate (18.2%) and patients with urticaria-like lesions had the lowest mortality rate (2.2%). Conclusion: The mere occurrence of skin manifestations in COVID-19 patients is not an indicator for the disease severity, and it highly depends on the type of skin lesions. Chilblain-like and vascular lesions are the ends of a spectrum in which from chilblain-like to vascular lesions, the severity of the disease increases, and the patient's prognosis worsens. Those with vascular lesions should also be considered as high-priority patients for further medical care.

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.

Cutaneous leukocytoclastic vasculitis secondary to COVID-19 infection: A case report

COVID-19 is a novel disease that mostly affects the respiratory system but as the number of cases is rising significantly around the world, more extra-respiratory manifestations are being reported among which are various dermatologic manifestations.

Cutaneous Manifestations in Patients With COVID-19: Clinical Characteristics and Possible Pathophysiologic Mechanisms

The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections soon led to a pandemic with serious health, economic, political, and cultural repercussions across the globe. The disease caused by SARS-CoV-2, coronavirus disease 2019 (COVID-19), is a multisystemic disease that requires a multidisciplinary approach involving specialists from all fields and levels of care. In this article, we review the literature on the diverse cutaneous manifestations associated with COVID-19. We also describe the pathophysiologic mechanisms proposed to date and their possible association with these manifestations. Finally, we propose a system for classifying the cutaneous manifestations of COVID-19 according to their underlying pathophysiologic mechanisms and prognosis.