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AB1084 PECULIARITIES OF ERYTHEMA NODOSUM ASSOCIATED WITH SARCOIDOSIS AND BACTERIAL-VIRAL INFECTION IN RHEUMATOLOGIST PRACTICE

Background Erythema nodosum (EN) is a nonspecific immune inflammatory syndrome, which is a septal panniculitis without vasculitis. Often EN acts as one of the symptoms of systemic pathology, which can cause late diagnosis and, accordingly, the appointment of adequate therapy. Objectives: to study clinical, laboratory and radiological data in EN in the acute form of sarcoidosis (SAR) and EN associated with bacterial and viral infection in patients sent to the rheumatology center. Methods The study included 312 patients (61 men and 251 women, age 35.4 ± 8.2 years) who applied to the clinic with a referral diagnosis of EN in 2007-2017. The median duration of the disease was 1.6 [0.3;4.7] months. All patients underwent a comprehensive clinical examination and laboratory and instrumental examination of biochemical, serological (ASL-O, antibodies against chlamydia and Mycoplasma of 2 classes, ureaplasmas, herpes viruses of type I and II, cytomegalovirus, Epstein-Barr virus, hepatitis B/C, Yersinia, HIV, etc.) and immunological parameters, radiography or computed tomography (CT) of the chest organs. Results 145 patients (46.4%) were diagnosed with SAR (34 men and 111 women). EN associated with bacterial-viral infection was detected in 167 patients (53.5%). Serological examination of these patients showed an increase of ≥3 times the levels of antibodies to Herpesviridae (79 people), M. pneumonie (15), CL. Pneumonia (11), Y. enterocolitica (11), Chl. trachomatis (9), M. hominis (6), increase of ASL-O (57). EN with SAR is characterized by: the duration of the disease up to 6 months (odds ratio (OR) 7,320, 95% confidence interval (CI) 2,297– 23,329, p<0.005), multiple diffuse lesions on the legs and single diffuse lesions on the thighs and/or forearms (OR 15,500, 95% CI 1,983–121,132; p<0.005), lesions of ankle joints (OSH 35,905, 95% CI 9,523–135,365; p<0.005), high CRP level (OR 5,429 95% CI: 2,164–13,618; p<0.005). Predictors of the formation of the CT phenomenon of “frosted glass” in ATS were male sex (OR 6.5; DI 1.2–35; p = 0.026) and the presence of conglomerates of nodes (OR 4.8; DI 1.4–16.1; p = 0.01). Postinfectious EN was characterized by its development typically before the age of 30 (OR 0.825, 95% CI 0.328-2.077, p<0.005), the symptom of “blooming” bruise (OR 0.028, 95% CI 0.009–0.092, p<0.005), an increase in antistreptolysin-O (OR 0.035, 95% CI 0.006–0.207, p<0.005). Within 1 year of follow-up, 72% of patients with SAR EN did not relapse, and the joint syndrome almost completely regressed. Postinfectious EN recurred within 1 year in 38 people due to: exacerbation of chronic tonsillitis (14), ARVI/hypothermia (10), stress (5), violation and ineffectiveness of prescribed therapy (9). Conclusion Post-infectious EN is somewhat more common than EN in SAR. The latter is characterized by greater severity of clinical parameters and high parameters of inflammatory activity. These features should be borne in mind when carrying out differential diagnosis in patients with EN. Disclosure of Interests None declared