High prevalence of cryofibrinogenemia in patients with chilblains during the COVID-19 outbreak

A very rare cause of blue finger: A case-based review

Introduction

Cryofibrinogen is an abnormal, cold-insoluble protein composed of a combination of fibrinogen, fibrin, and fibronectin. Cryofibrinogenemia can be essential (e.g. primary) or secondary to various conditions. While low levels of cryofibrinogen can be seen in asymptomatic healthy individuals without evidence of clinical features typical of cryofibrinogenemia, cryofibrinogenemia associated with clinical features is considered very rare. The clinical features of cryofibrinogenemia ranges from skin manifestations, including Raynaud's phenomenon and livedo reticularis, to more severe organ-threatening manifestations such as tissue ischemia and gangrene.

Case description

We report a case of a 48-year-old male who presented with blue finger and palpable purpura on his distal extremities. Laboratory workup was positive for anti-nuclear antibodies, anti-double-stranded DNA, anti-ribonucleoprotein, and rheumatoid factor, while antineutrophil cytoplasmic antibodies and cryoglobulins were negative. Testing for hypercoagulable states and infectious etiologies was unrevealing. Later, angiographic computed tomography showed multiple pulmonary embolisms and disruption of blood flow to the left fifth digit. As the aforementioned workup could not explain the presence of the thrombus by a thromboembolic cause, a search for an in situ cause other than antiphospholipid syndrome was initiated and concentrated mainly on cryofibrinogenemia. Blood samples collected using prewarmed anticoagulant containing tubes were sent to central lab familiar with performing the test. Two weeks later, a positive result for the presence of cryofibrinogen confirmed the diagnosis of cryofibrinogenemia. Due to the presence of multiple signs compatible with mixed connective tissue disease, he was diagnosed with cryofibrinogenemia secondary to mixed connective tissue disease, and treatment with prednisone, low-molecular-weight heparin, prostacyclin and hydroxychloroquine was initiaed with favorable outcome.

Conclusion

Cryofibrinogenemia is a rare and underdiagnosed condition. Clinicians should be aware of this cryopathy especially in the cases of Raynaud's phenomenon and ischemic ulcers not explained by other causes. Precautions must be taken during the diagnostic process, and therapy should be given as soon as possible.

Cryofibrinogenemia: What Rheumatologists Should Know

Cryofibrinogenemia refers to the presence of cryofibrinogen in plasma. This protein has the property of precipitating at lower temperatures. Cryofibrinogenemia is a rare disorder, clinically characterized by skin lesions, such as ulcers, necrosis, livedo reticularis, arthralgia, thrombosis, and limb ischemia. These features are most often observed in rheumatological practice and consist in the differential diagnoses of antiphospholipid syndrome, primary vasculitis, thrombotic thrombocytopenic purpura, and cryoglobulinemia. Classical histopathological findings include the presence of thrombi within the lumen of blood vessels of the skin without vasculitis. To date, there are no validated classification criteria. Management includes corticosteroids, immunosuppressive therapy, anticoagulants, and fibrinolytic agents. This narrative review aims to make physicians, particularly rheumatologists, aware of existence of this underdiagnosed condition. There are no epidemiological studies evaluating the prevalence of cryofibrinogenemia in different rheumatological disorders. Studies are also required to investigate if certain features of rheumatological diseases are related to the presence of cryofibrinogenemia.

Chilblain or Perniosis-like Skin Lesions in children during the COVID-19 pandemic: A Systematic Review of Articles

COVID toes or chilblain-like skin lesions represent a widespread and specific skin presentation in the feet attributed to COVID-19 infection. They may last for several months. We conducted this study to investigate chilblain-like lesions in children during the COVID-19 pandemic, any predisposition, location, clinical course, and prognosis. We searched Google Scholar, Scopus, and Medline (PubMed) databases using the following keywords: "Coronavirus" OR "COVID-19" AND "Chilblains" OR "Pernio" OR "Perniosis" OR "Children" OR "Cutaneous" OR "skin." The inclusion criteria were: studies that described the specific vascular skin lesion. studies that included patients that were aged > one month till 18 years. . Case reports, case series, retrospective or prospective cohort studies, case-control studies. Twenty-eight articles were included. The total number of children with CLL was 433. The mean age of children presenting CLL during the COVID-19 pandemic was estimated as 12.58 ± 2.15. Of note, 53.6% of them were male. The nasopharyngeal SARS-CoV-2 RT-PCR test and anti-SARS-CoV-2 antibodies were mostly negative for the virus. In conclusion, it is crucial to be familiar with various presentations of COVID-19 infection and their clinical significance to approach the earliest diagnosis, immediate treatment, estimate the prognosis and finally isolate the patients to prevent spreading. Chilblain-like lesions as a possible cutaneous presentation of COVID-19 in children may last several months with the indolent course.

Type I interferon response and vascular alteration in chilblain-like lesions during the COVID-19 outbreak

Background

The outbreak of chilblain‐like lesions (CLL) during the COVID‐19 pandemic has been reported extensively, potentially related to SARS‐CoV‐2 infection, yet its underlying pathophysiology is unclear.

Objectives

To study skin and blood endothelial and immune system activation in CLL in comparison with healthy controls and seasonal chilblains (SC), defined as cold‐induced sporadic chilblains occurring during 2015 and 2019 with exclusion of chilblain lupus.

Methods

This observational study was conducted during 9–16 April 2020 at Saint‐Louis Hospital, Paris, France. All patients referred with CLL seen during this period of the COVID‐19 pandemic were included in this study. We excluded patients with a history of chilblains or chilblain lupus. Fifty patients were included.

Results

Histological patterns were similar and transcriptomic signatures overlapped in both the CLL and SC groups, with type I interferon polarization and a cytotoxic–natural killer gene signature. CLL were characterized by higher IgA tissue deposition and more significant transcriptomic activation of complement and angiogenesis factors compared with SC. We observed in CLL a systemic immune response associated with IgA antineutrophil cytoplasmic antibodies in 73% of patients, and elevated type I interferon blood signature in comparison with healthy controls. Finally, using blood biomarkers related to endothelial dysfunction and activation, and to angiogenesis or endothelial progenitor cell mobilization, we confirmed endothelial dysfunction in CLL.

Conclusions

Our findings support an activation loop in the skin in CLL associated with endothelial alteration and immune infiltration of cytotoxic and type I IFN‐polarized cells leading to clinical manifestations.

Pediatric Rheumatologic Effects of COVID-19

A multisystem inflammatory syndrome (MISC) can result from COVID-19 infection in previously healthy children and adolescents. It is potentially life threatening and is treated initially with intravenous immunoglobulin and aspirin but may require anti-inflammatory monoclonal antibody treatment in severe cases. SARS-CoV-2 infection can cause macrophage activation syndrome, chilblains, and flares of existing rheumatologic diseases. The pandemic has led to later presentation of some rheumatologic conditions as parents and patients have avoided health care settings. PubMed and Google scholar have been utilized to review the literature on the rheumatologic conditions resulting from COVID-19 and the current treatment options.

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.

Nails and COVID-19 - A comprehensive review of clinical findings and treatment

The SARS‐CoV‐2 infection, responsible for COVID‐19, has raised the interest for infection‐associated muco‐cutaneous symptoms. While dermatologic symptoms in general gained an increasing awareness, affection of the nail organ has been mentioned only recently. We provide a narrative review on COVID‐19 manifestation on the nail organ and add symptoms induced by personal protective measures and SARS‐CoV‐2 vaccination. Available treatment options are discussed.

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.