Septal panniculitis as manifestation of COVID-19: own data

Objective: to study the clinical and laboratory features of erythema nodosum (EN) in a cohort of patients with COVID-19 referred to a rheumatological center.Patients and methods. During 2020–2021 years 21 patients (18 women and 3 men, mean age 43.2±11.4 years) with EN and polyarthralgia/arthritis were examined. Depending on the time of EN and articular syndrome associated with COVID-19 development, patients were divided into three groups: 1) up to 4 weeks – acute COVID (symptoms potentially associated with infection); 2) from 4 to 12 weeks – ongoing symptomatic COVID and 3) more than 12 weeks – post-COVID syndrome (persistent symptoms not associated with an alternative diagnosis). All patients underwent a comprehensive clinical, laboratory and instrumental examination, including ultrasound of the joints and chest computed tomography (CT), as well as pathomorphological examination of skin and subcutaneous adipose tissue from the site of the node (in 9 cases).Results and discussion. Based on the anamnesis data, COVID-19 in the study cohort had mild (in 13 patients) and moderate (in 8) severity. Two patients (21 years old and 23 years old) with mild severity of the disease noted red painful (45 mm on the visual analogue scale of pain) nodes on the legs and polyarthralgia for the first time on the 2nd – 3rd day from respiratory symptoms onset. In 9 (52.3%) patients, mainly with a mild course, similar skin changes were detected 24.5±7.6 days after active COVID-19 relieve, i.e. during the period of ongoing symptomatic COVID. In 8 (38%) patients, including 6 with moderate severity of the disease, the appearance of nodes was noted after 85.6±12.3 days, which corresponded to the post-COVID syndrome.At the time of examination, complaints of skin rashes and joint pain were reported in 100 and 71.4% of patients, respectively. 67% of patients had shortness of breath, weakness, cough, sweating and myalgia. Subfebrile fever had 5 (24%) patients, mainly with ongoing symptomatic COVID (3 patients). In the overwhelming majority of cases (86%), EN was located on the anterior and lateral surfaces of shins, less often on the posterior and medial surfaces. It is noteworthy that the affection of more than 50% of the surface of the lower and upper extremities was associated with the number of nodes (p<0.02), the level of CRP (p<0.03) and the presence of post-COVID syndrome (p<0.2). Fifteen (71.4%) patients had arthralgias, mainly of ankle (80%) and knee (53.3%) joints.Laboratory abnormalities included: median ESR was 34 [12; 49] mm/h, CRP level – 9 [2; 32] mg/l. The results of the polymerase chain reaction for SARS-CoV-2 were negative in all patients. In 100% of cases IgG antibodies to SARS-CoV-2 were detected and in 52.3% – IgM antibodies. On chest CT 5% lung affection was detected in 43% of patients, 5–25% lesion in 57.1% of patients, 8 (38%) of whom were with post-COVID syndrome. Pathomorphological examination of the nodes showed signs of septal panniculitis.Conclusion. When EN, associated with SARS-CoV-2 appears it is important to suspect a post-infectious manifestation in time, based on the clinical picture of the disease and to determine the scope of further examination and adequate treatment.