AB1362 Specific features of the clinical course and outcomes of erythema nodosum, associated with infection
Authors: B. Belov, N. Savushkina, O. Egorova
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Erythema nodosum (EN) is the <i>most common</i> type of septal panniculitis (Pn) without vasculitis. The <i>prevailing</i> identifiable cause of EN in paediatric population is bacterial infection (Streptococcus), while in adults sarcoidosis and streptococcal infection are considered to be the most common etiological factors. <h3>Objectives</h3> The aim of the current study is to evaluate specific features of the clinical course and outcomes of EN, associated with infection, in rheumatology practice. <h3>Methods</h3> The study included 121pts (112 females—92,6%, 9 males—7,4%, mean age 38,9±12,6 y) who were on the record at VA Nasonova Research Institute of Rheumatology during 7 years with referral diagnosis «erythema nodosum». The disease duration varied from 1 week to 20 years. Patient's assessment included general clinical examination, immunological and <i>serological tests for Chlamidia</i> (<i>Chl. Pneumoniae, Chl. trachomatis</i>), Mycoplasma (<i>M. pneumoniae, M. hominis</i>), Ureaplasma, Herpes viruses type I and II, Cytomegalovirus, Epstein-Barr virus, Yersinia, HBV and HCV, HIV, anti-streptolysin O (ASO) using ELISA and immunoturbidimertry. The outcomes were assessed in 1–6 years. <h3>Results</h3> EN association with infection was identified in 32 pts (30 females, 2 males, mean age 39,6±13 y). Chronic conditions prior to EN onset were found in 12 pts (37%): tonsillitis—in 8 pts (25%), endometriosis—in 1 (3%), bronchitis—in 1 (3%), colpitis—in 1 (3%), toxoplasmosis—in 1 (3%). Elevated ASO titers were documented in more than half cases (18 (56,25%) pts). "Blooming bruise" symptom was characteristic for this population (p&lt;0,0001). Clear clinical and laboratory signs of active inflammation were not found. Based on etiological agent all pts were divided into 3 groups: Group I—with bacterial infection (5 pts (15%)), Group II—with viral infection (11 pts (35%)), Group III—with mixed bacterial and viral infection (16 pts (50%)). Rapid nodule regression was strongly associated with elevated ASO titers at baseline (p=0,02) and presence of bacterial agents (p=0,0007). Recurrences were documented in 13 pts (40,6%), among them 7 (54,1%) cases were triggered by ARVI/common frigorism, 2 (15,3%) cases—by stress, 2 (15,3%) cases – by non-compliance or treatment failure, 2 (15,3%) – by exacerbation of chronic tonsillitis. There was no statistically significant association between intake of individual medications and full reversal of the disease. There was 1 (8% from total number) recurrence episode in Group I, 7 (54%) episodes—in Group II, and 5 (38%)—in Group III. Recurrent disease inversely correlated with affected surface area (affected leg surfaces) (p=0,03). Pts who achieved nodular regression had elevated ASO at EN onset (p=0,00008), in contrast to pts with recurrent disease. <h3>Conclusions</h3> Streptococcus spp (56,3%) seem to be the leading cause of EN associated with infection. Lab verification of streptococcal infection with subsequent adequate antibacterial therapy facilitates the favourable clinical course of EN. <h3>Acknowledgements</h3> The study had no sponsorship. <h3>Disclosure of Interest</h3> None declared