Cutaneous manifestations of SARS-CoV-2: A 2-center, prospective, case-controlled study

SARS-CoV-2-Induced Vasculitic Skin Lesions Are Associated with Massive Spike Protein Depositions in Autophagosomes

In patients infected with severe acute respiratory syndrome coronavirus 2, vasculopathic changes of the skin are associated with a severe prognosis. However, the pathogenesis of this vasculopathy is not conclusively clarified. In this study, 25 prospectively collected skin samples from patients with COVID-19-related skin lesions were examined for vasculopathic changes and, in case of vasculitis, were further analyzed with electron microscopy and immunohistochemistry. Vasculopathy was observed in 76% of all COVID-19-related inflammatory skin lesions. Visual endothelial changes without manifest leukocytoclastic vasculitis were found in 60% of the COVID-19-related skin lesions, whereas leukocytoclastic vasculitis was diagnosed in 16%. In the cases of vasculitis, there were extensive spike protein depositions in microvascular endothelial cells that colocalized with the autophagosome proteins LC3B and LC3C. The autophagy protein complex LC3-associated endocytosis in microvascular endothelial cells seems to be an important pathogenic factor for severe acute respiratory syndrome coronavirus 2-related vasculitis in the skin. On ultrastructural morphology, the vasculitic process was dominated by intracellular vesicle formation and endothelial cell disruption. Direct presence of severe acute respiratory syndrome coronavirus 2 particles in the skin was not observed. Therefore, our results suggest that instead of direct viral infection, dermal vasculitic lesions in COVID-19 are caused by severe acute respiratory syndrome coronavirus 2 spike protein deposition followed by endothelial damage with activation of autophagy.

Prevalence of cutaneous manifestations in COVID-19: A meta-analysis

The global epidemic of coronavirus disease 2019 (COVID-19) endangers more and more people. Many studies on cutaneous manifestations related to COVID-19 have emerged, but their prevalence has varied widely. The objective of this study was to conduct a meta-analysis estimating the prevalence of skin manifestations in COVID-19. Four databases PubMed, Web of Science, CBM, and CNKI were searched, and the results were screened by two reviewers. A random-effects model was used to evaluate the overall prevalence. Heterogeneity was assessed by I² . Further subgroup analyses were conducted by region, sample size, sex, age, and severity of COVID-19. A funnel plot and Egger's test were performed to assess publication bias. The pooled prevalence of cutaneous manifestation of 61 089 patients in 33 studies was 5.6% (95% confidence intervals [CI] = 0.040-0.076, I²  = 98.3%). Severity of COVID-19 was probably the source of heterogeneity. Studies with sample size <200 report higher prevalence estimates (10.2%). The prevalence of detailed types was as follows: maculopapular rash 2%, livedoid lesions 1.4%, petechial lesions 1.1%, urticaria 0.8%, pernio-like lesions 0.5%, vesicular lesions 0.3%. Petechial lesions and livedoid lesions contain a higher proportion of severe patients than other skin manifestations. The prevalence rates of pernio-like lesions, urticaria and petechial lesions vary greatly in different regions.

Skin manifestations associated with COVID-19

This article will address the main aspects of skin manifestations associated with COVID-19, based on a review of the literature published to date. Since the beginning of the pandemic, more than 1,500 articles have been published on the subject. Regarding the pathophysiology, it is believed that the same mechanisms responsible for the disease in the main target organs also act in the skin, although they are not yet fully elucidated. The actual frequency of dermatological manifestations remains uncertain – it can range from 0.2% to 45%, being close to 6% in systematic reviews. Pioneering studies of large case series conducted in European countries and the USA provide the first information on the main skin manifestations associated with COVID-19 and propose classifications regarding their clinical presentation, pathophysiology, as well as their frequencies. Although there is yet no consensus, maculopapular eruptions are considered the most frequent presentations, followed by erythema pernio-like (EPL) lesions. Manifestations such as urticaria, vesicular conditions and livedo/purpura/necrosis are rare. The time of onset, severity, need for specific treatment and prognosis vary according to the clinical presentation pattern. The increasing histopathological description of skin conditions can contribute to the diagnosis, as well as to the understanding of the pathophysiology. Also, in the dermatological field, the relationship between COVID-19 and androgens has been increasingly studied. Despite all the generated knowledge, the actual biological meaning of skin manifestations remains uncertain. Therefore, the exclusion of the main differential diagnoses is essential for the correlation between skin manifestation and COVID-19.

Microvascular Skin Manifestations Caused by COVID-19

Hypercoagulability and vascular injury, which characterize morbidity in COVID-19 disease, are frequently observed in the skin. Several pathomechanisms, such as inflammation caused by angiotensin-converting enzyme 2-mediated uptake into endothelial cells or SARS-CoV-2-initiated host immune responses, contribute to microthrombus formation and the appearance of vascular skin lesions. Besides pathophysiologic mechanisms observed in the skin, this review describes the clinical appearance of cutaneous vascular lesions and their association with COVID-19 disease, including acro-ischemia, reticular lesions, and cutaneous small vessel vasculitis. Clinicians need to be aware that skin manifestations may be the only symptom in SARS-CoV-2 infection, and that inflammatory and thrombotic SARS-CoV-2-driven processes observed in multiple organs and tissues appear identically in the skin as well.