AB0912 Revisiting The Differential Diagnosis of Panniculitis
Authors: O.N. Egorova, B.S. Belov, Y.A. Karpova, N.M. Savushkina, S.G. Radenska-Lopovok
Journal: Annals of the Rheumatic Diseases (2016)

<h3>Background</h3> Panniculitis (Pn) is a group of heterogeneous inflammatory diseases characterized by involvement of the subcutaneous fat (SF), locomotor system and viscera. Challenges in identification of Pn are associated with multiplicity of clinical and pathomorphological types alongside with the absence of specific Pn markers. <h3>Objectives</h3> to identify and analyze the diagnostic features of lipodermatosclerosis (LDS) as one of lobular Pn (LPn) varieties. <h3>Methods</h3> 550 patients with referral diagnosis of "erythema nodosum" (EN), "panniculitis", or "vasculitis" were thoroughly evaluated according to the in-house diagnostic algorithm. <h3>Results</h3> LPn was verified in 132 patients after through examination. LDS with disease duration 18,97±7,4 mo was found in 53 (9,6%) out of them (M-3, F–50, age 18- 80 y.). 32 patients were overweight with average body mass 91.5±21.8 kg. Inflammation in predominantly lower inner leg subcutaneous fat was documented in 37 pts (54,7%) resulting in the inverted coke bottle appearance of the lower leg (79,2%) (<i>p</i>=.00556). All main types of Pn clinical course were present: acute (up to 3 mo), subacute (3 to 6 mo) and chronic (&gt;6 mo). Acute disease was diagnosed in 20 pts (37,7%) aged 51,8±15,7 y., with indurated non-demarcated pink nodules existing for 1,47±0,3 mo.(<i>p</i>=.001). Subacute disease was found in 12 pts (22,6%) aged 57,50±12,1 y. with average disease duration 4,7±1,3 mo., dark red nodules and inverted coke bottle appearance of the lower leg in 91,67% cases. Chronic Pn with disease duration 43,3±24,0 mo was documented in 21 pts (39,6%) aged 56,1±11,9 y, with demarcated red-brownish nodules and inverted coke bottle appearance of the lower leg in 17 cases (80,95%). The risk of lower leg deformity was increased 2,3-fold in pts with chronic disease vs acute (95%, CI 1,2–4,4,<i>p</i>=.003). Asymmetric pattern of nodules was present in 70% of acute and subacute disease, symmetric pattern was found in 50% of chronic cases (<i>p</i>=.003). ROC-analysis showed with 86% sensitivity and 58% specificity that palpatory evaluation of pain in LDS using VAS corresponded with 40 mm cut-off value. In 46% of cases skin lesions were accompanied by polyarthralgia (in 15 pts), and myalgia (in 12 pts) with insignificant increase of inflammation activity markers. Chronic venous insufficiency lasting for 10,2±1,3 years and verified by US Doppler scanning of the lower extremities veins was found in 28 pts (including 19 with chronic LDS) (<i>p</i>&lt;0,05). Pathomorphological examination of skin and subcutaneous fat biopsy samples in 7 pts confirmed lobular Pn-LDS with sclerosis of borderline fatty tissue and of small arteries in hypoderma. <h3>Conclusions</h3> LDS is a variation of LPn. Identified predisposing factors include female gender, middle age, increased body mass and chronic venous failure in lower extremities. Asymmetric nodules of specific color on the inner leg and inverted coke bottle appearance of the lower leg are established diagnostic criteria for LDS. Successful diagnosis is possible with detailed history case, adequate evaluation of clinical, laboratory and instrumental modalities. <h3>Disclosure of Interest</h3> None declared