A retrospective study on the prevalence of anti-phospholipid antibodies, thrombotic events and cutaneous signs of vasculopathy in 173 hospitalized COVID-19 patients.

BACKGROUND: Hypercoagulability is a risk factor of thromboembolic events in COVID-19. Anti-phospholipid (aPL) antibodies have been hypothesized to be involved. Typical COVID-19 dermatological manifestations of livedo reticularis and digital ischemia may resemble cutaneous manifestations of anti-phospholipid syndrome (APS). OBJECTIVES: To investigate the association between aPL antibodies and thromboembolic events, COVID-19 severity, mortality, and cutaneous manifestations in patients with COVID-19. METHODS: aPL antibodies [anti-beta2-glycoprotein-1 (B2GP1) and anti-cardiolipin (aCL) antibodies] were titered in frozen serum samples from hospitalized COVID-19 patients and the patients' clinical records were retrospectively analyzed. RESULTS: 173 patients were enrolled. aPL antibodies were detected in 34.7% of patients, anti-B2GP1 antibodies in 30.1%, and aCL antibodies in 10.4%. Double positivity was observed in 5.2% of patients. Thromboembolic events occurred in 9.8% of patients, including 11 pulmonary embolisms, 1 case of celiac tripod thrombosis, and six arterial ischemic events affecting the cerebral, celiac, splenic, or femoral-popliteal arteries or the aorta. aPL antibodies were found in 52.9% of patients with vascular events, but thromboembolic events were not correlated to aPL antibodies (adjusted OR = 1.69, p = 0.502). Ten patients (5.8%) had cutaneous signs of vasculopathy: nine livedo reticularis and one acrocyanosis. No significant association was observed between the presence of cutaneous vasculopathy and aPL antibodies (p = 0.692). CONCLUSIONS: Anti-phospholipid antibodies cannot be considered responsible for hypercoagulability and thrombotic events in COVID-19 patients. In COVID-19 patients, livedo reticularis and acrocyanosis do not appear to be cutaneous manifestations of APS.

In vitro diagnostics for the medical dermatologist. Part II: Hypercoagulability tests.

The skin often provides initial clues of hypercoagulability with features such as livedo reticularis, livedo racemosa, retiform purpura, necrosis, and ulcerations. Because these cutaneous manifestations are nonspecific, laboratory testing is often needed to evaluate for underlying causes of hypercoagulability. Importantly, these disorders are reported to be the most common mimicker, resulting in an erroneous diagnosis of pyoderma gangrenosum. Understanding inherent properties of, and indications for, available tests is necessary for appropriate ordering and interpretation of results. Additionally, ordering of these tests in an indiscriminate manner may lead to inaccurate results, complicating the interpretation and approach to management. This second article in this continuing medical education series summarizes information on methodology, test characteristics, and limitations of several in vitro laboratory tests used for the work up of hypercoagulability and vasculopathic disease as it pertains to dermatologic disease.