The differing pathophysiologies that underlie COVID-19-associated perniosis and thrombotic retiform purpura: a case series

Inflammatory Skin Lesions in Three SARS-CoV-2 Swab-Negative Adolescents: A Possible COVID-19 Sneaky Manifestation?

Coronavirus disease 19 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is associated with various clinical manifestations, including skin lesions. In particular, during the COVID-19 pandemic lock-down period numerous chilblain-like lesions, mainly located on the feet, were observed in adolescents. The latter were often asymptomatic or associated with very mild respiratory symptoms. Here, we report three cases of acral nodular lesions in SARS-CoV-2 swab-negative adolescents with histological findings of chronic immune-mediated inflammation and immunohistochemical evidence of SARS-CoV-2 spike glycoproteins in endothelial cells and eccrine sweat glands. In one of these cases, the virus presence was confirmed by electron microscopy.

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.

A Missing Link: Engagements of Dendritic Cells in the Pathogenesis of SARS-CoV-2 Infections

Dendritic cells (DC) connect the innate and adaptive arms of the immune system and carry out numerous roles that are significant in the context of viral disease. Their functions include the control of inflammatory responses, the promotion of tolerance, cross-presentation, immune cell recruitment and the production of antiviral cytokines. Based primarily on the available literature that characterizes the behaviour of many DC subsets during Severe acute respiratory syndrome (SARS) and coronavirus disease 2019 (COVID-19), we speculated possible mechanisms through which DC could contribute to COVID-19 immune responses, such as dissemination of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to lymph nodes, mounting dysfunctional inteferon responses and T cell immunity in patients. We highlighted gaps of knowledge in our understanding of DC in COVID-19 pathogenesis and discussed current pre-clinical development of therapies for COVID-19.

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 infection and stroke risk

Coronavirus disease 2019 (COVID-19), due to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in Wuhan city, China in December 2019 and rapidly spread to other countries. The most common reported symptoms are fever, dry cough, myalgia and fatigue, headache, anorexia, and breathlessness. Anosmia and dysgeusia as well as gastrointestinal symptoms including nausea and diarrhea are other notable symptoms. This virus also can exhibit neurotropic properties and may also cause neurological diseases, including epileptic seizures, cerebrovascular accident, Guillian barre syndrome, acute transverse myelitis, and acute encephalitis. In this study, we discuss stroke as a complication of the new coronavirus and its possible mechanisms of damage.

SARS-CoV-2 has not been detected directly by electron microscopy in the endothelium of chilblain lesions: reply from the authors

Linked Articles: Colmenero et al. Br J Dermatol 2021; 183:729–737. Brealey and Miller. Br J Dermatol 2021; 184:186. Colmenero et al. Br J Dermatol 2021; 183:1170–1171.

Cutaneous and histopathological features of coronavirus disease 2019 in pediatrics: A review article

Prevalence of dermatological manifestations of coronavirus disease 2019 (COVID‐19) is estimated between 0.25% and 3% in children and adolescents. In this review article, we decided to describe the cutaneous and histopathological manifestations of COVID‐19 infection in pediatrics. We searched published articles in PubMed database for key words of “children” or “pediatric” and “cutaneous” or “dermatology” or “skin” and “COVID‐19” or “SARS‐CoV‐2” or “Coronavirus disease 2019” in abstract or title from December of 2019 until September 2020. Finally, 38 articles were selected. The majority of patients were between 11 and 17 years old with predominantly male gender. Most of the patients were either asymptomatic or had a few general symptoms. The latency time from appearance of general symptoms to cutaneous ones was between 1 day and weeks. Skin lesions faded between 3 and 88 days without any sequelae, spontaneously or with either topical or systemic corticosteroids. Skin manifestations were chilblain‐like (pseudochilblain), erythema multiforme‐like, dactylitis, acral erythema, acute urticaria, livedo reticularis, mottling, acro‐ischemia, generalized maculopapular lesions, eyelid dermatitis, miliaria‐like, varicelliform lesions, and petechiae and/or purpura. Kawa‐COVID‐19 patients were presented more frequently with cardiogenic shock, neurological symptoms, lymphocytopenia, and thrombocytopenia as compared to classic Kawasaki's disease. Furthermore, more number of cases were resistant to the first‐line treatments.

Impaired type I interferon response in SARS-CoV-2 infection: looking through the cutaneous window

Linked Article: Magro et al. Br J Dermatol 2021; 184:141–150.

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.

Skin Manifestations in COVID-19: Prevalence and Relationship with Disease Severity

BACKGROUND

Data on the clinical patterns and histopathology of SARS-CoV-2 related skin lesions, as well as on their relationship with the severity of COVID-19 are limited.

METHODS AND MATERIALS

Retrospective analysis of a prospectively collected cohort of patients with SARS-CoV-2 infection in a teaching hospital in Barcelona, Spain, from 1 April to 1 May 2020. Clinical, microbiological and therapeutic characteristics, clinicopathological patterns of skin lesions, and direct immunofluorescence and immunohistochemical findings in skin biopsies were analyzed.

RESULTS

Fifty-eight out of the 2761 patients (2.1%) either consulting to the emergency room or admitted to the hospital for COVID-19 suspicion during the study period presented COVID-19 related skin lesions. Cutaneous lesions could be categorized into six patterns represented by the acronym "GROUCH": Generalized maculo-papular (20.7%), Grover's disease and other papulo-vesicular eruptions (13.8%), livedo Reticularis (6.9%), Other eruptions (22.4%), Urticarial (6.9%), and CHilblain-like (29.3%). Skin biopsies were performed in 72.4%, including direct immunofluorescence in 71.4% and immunohistochemistry in 28.6%. Patients with chilblain-like lesions exhibited a characteristic histology and were significantly younger and presented lower rates of systemic symptoms, radiological lung infiltrates and analytical abnormalities, and hospital and ICU admission compared to the rest of patients.

CONCLUSION

Cutaneous lesions in patients with COVID-19 appear to be relatively rare and varied. Patients with chilblain-like lesions have a characteristic clinicopathological pattern and a less severe presentation of COVID-19.

Docked severe acute respiratory syndrome coronavirus 2 proteins within the cutaneous and subcutaneous microvasculature and their role in the pathogenesis of severe coronavirus disease 2019

The purpose of this study was to examine the deltoid skin biopsy in twenty-three patients with coronavirus disease 2019 (COVID-19), most severely ill, for vascular complement deposition and correlate this with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral RNA and protein localization and ACE2 expression. Deltoid skin microvascular complement screening has been applied to patients with various systemic complement-mediated microvascular syndromes, best exemplified by atypical hemolytic uremic syndrome. In 21 of 23 cases, substantial microvascular deposition of complement components was identified. The two patients without significant complement deposition included one patient with moderate disease and a severely ill patient who although on a ventilator for a day was discharged after 3 days. The dominant microvascular complement immunoreactant identified was the terminal membranolytic attack complex C5b-9. Microvascular complement deposition strongly colocalized in situ with the SARS-CoV-2 viral proteins including spike glycoproteins in the endothelial cells as well as the viral receptor ACE2 in lesional and nonlesional skin; viral RNA was not evident. Microvascular SARS-CoV-2 viral protein, complement, and ACE2 expression was most conspicuous in the subcutaneous fat. Although the samples from severely ill patients with COVID-19 were from grossly normal skin, light microscopically focal microvascular abnormalities were evident that included endothelial cell denudement, basement membrane zone reduplication, and small thrombi. It is concluded that complement activation is common in grossly normal skin, especially in the subcutaneous fat which may provide a link between severe disease and obesity, in people with severe COVID-19, and the strong colocalization with the ACE2 receptor and viral capsid proteins without viral RNA suggests that circulating viral proteins (ie, pseudovirions) may dock onto the endothelial of these microvessels and induce complement activation.

Cutaneous Manifestations in Adult Patients with COVID-19 and Dermatologic Conditions Related to the COVID-19 Pandemic in Health Care Workers

PURPOSE OF REVIEW

COVID-19 (coronavirus viral disease 2019), due to the novel SARS-CoV-2, may present with different types of cutaneous manifestations of varying pathophysiology. During the ongoing pandemic, publications reporting dermatologic findings in COVID-19 continue to emerge.

RECENT FINDINGS

Cutaneous vasculopathy and microthrombus-related changes including acral and sacral lesions, retiform purpura, livedo reticularis, and cutaneous vasculitis are notable findings in adult patients. Other exanthems include urticaria or angioedema, morbilliform/maculopapular exanthems, erythema multiforme, and vesicular eruptions. Increased recognition of these findings, especially those consistent with cutaneous microthrombi or vasculitis, is of particular importance. Additionally, occupational dermatologic disease related to extended personal protective equipment (PPE) use, such as skin damage and irritant or allergic contact dermatitis (ACD), represents another emerging problem amidst the pandemic. In this review, we highlight the various cutaneous manifestations associated with COVID-19 in adult patients and occupational dermatitis in health care workers (HCWs) caring for this patient population.

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.