Background Panniculitis (Pn) is a group of heterogeneous inflammatory diseases characterized by involvement of the subcutaneous fat (SF), musculoskeletal system and internal organs.

Objectives to evaluate the clinical course and outcomes of Pn in a prospective study.

Methods 73 pts (F-64, M-9) aged 19 - 77 y., referred for examination and treatment to V.A. Nasonova Research Institute of Rheumatology with referral diagnoses of “erythema nodosum” (EN) and “panniculitis”, disease duration from 1 week to 13 years, were followed up. Patient evaluation included physical examination, lab tests (serum levels of α1-antitrypsin, amylase, lipase, ferritin, creatine phosphokinase (CPK), rheumatoid factor) (RF), ANF, anti-DNA, ANCA), bacteriological and serological tests, radiological examination (chest CT scan), ultrasound examinations of skin and SF around the nodules, tuberculin skin test and histopathology of nodular skin samples. Patients were re-tested during the follow up (FUP) when necessary. The FUP period lasted from 3 to 5 years.

Results based on clinical, lab and instrumental findings the following diagnoses were verified: EN, associated with infection (22 pts – Group1), lipodermatosclerosis (LDS) (15 pts – Group 2), Weber-Christian's Pn (11 pts – Group 3), Lőfgren syndrome (25 pts – Group 4). In Group 1 EN recurrences were documented in 10 (45%) pts during the FUP, presumably caused by: common cold (4), exacerbation of chronic tonsillitis (1), acute respiratory viral infection (ARVI) (1), stress (1), rapid down of dose of GCs (1), unknown cause (2). In Group 2 recurrences occurred in 9 (60%) pts due to stress (4), failure to observe anti-inflammatory therapy (hydroxychloroquine) (2), trauma (2), weight lifting (1). There were no recurrences in 3 pts from Group 2, nevertheless they failed to reach complete regression of the nodi, most probably due to poor compliance with treatment. 10 relapses (90,9%) registered in Group 3 were associated with absence/discontinuation of anti-inflammatory therapy (6), insufficient efficacy of administered anti-inflammatory therapy (2), and common cold (2). Relapse of nodules in 6 (24%) pts from Group 4 had the following plausible explanation: common cold /ARVI (5), GCs discontinuation (1). Two (2/7%) death were documented during the FUP: in 1 patient with LDS due to acute heart failure, and in 1 patient with Weber- Christian disease due to chronic cardio-pulmonary failure.

Conclusions common cold and viral infections were the leading causes of relapses in pts with EN associated with infection and with Lőfgren syndrome, while stress and absence/insufficient efficacy of anti-inflammatory therapy were the major causes of recurrence in pts with Weber-Christian Pn and LDS. In this Pn case series mortality was 2,7% during the FUP.

Disclosure of Interest None declared