POS0519 DETECTION OF PERIPHERAL SPONDYLOARTHRITIS FEATURES IN PATIENTS WITH ACNE INVERSA/ HIDRADENITIS SUPPURATIVA BY MUSCULOSKELETAL ULTRASOUND AND FLUORESCENCE OPTICAL IMAGING
Authors: S. Ohrndorf, J. Klotsche, T. Jakovljevicova, G. Schmittat, G. R. Burmester, G. Krönke, G. Kokolakis
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Hidradenitis suppurativa (HS) is a debilitating chronic inflammatory disease that affects the intertriginous skin sites, especially axillary, inguinal, and perianal [1]. In recent studies, a higher prevalence of spondyloarthritis (SpA) in the HS population than in the general population (with 1%) was presented, however, the reported prevalence rates demonstrated a wide range of 2.3%-28.2% (2, 3). Furthermore, the studies mainly referred to axial SpA in association with HS [2-4]. One recent study described an association between peripheral SpA (pSpA) features such as peripheral arthritis, enthesitis, and dactylitis with HS, but the self-reporting design of this study was a limitation [5]. <h3>Objectives:</h3> To investigate the prevalence of pSpA features both clinically and by the detection of synovitis, tenosynovitis and enthesitis by musculoskeletal ultrasound (MSUS) in B-mode (GS) and power Doppler (PD), and by fluorescence optical imaging (FOI). <h3>Methods:</h3> Adult HS patients presenting at the outpatient department of Dermatology (HS diagnosed by a dermatologist) with musculoskeletal symptoms suspicious for pSpA have been included in this monocenter study. Patients were examined by a rheumatologist for tender and swollen joints (TJC-68; SJC-66). The laboratory parameters CRP, ESR, and HLA-B27 were evaluated. MSUS was performed for the detection of synovitis and tenosynovitis (both wrists, MCP and (P)IP1-5, knees, MTP1-5) in GS and PD (each 0-3), and enthesitis (both common flexor and extensor tendons, quadriceps and patellar tendons, and Achilles tendons) in PD (0-3). FOI of both hands was done by the Xiralite method in a standardized manner using PrimaVista Mode (PVM) and three predefined phases (p1-p3). <h3>Results:</h3> In total, 25 HS patients with a disease duration of 8.5±8.4 years were included (72% female, mean age 47.3±9.6, mean BMI (kg/m<sup>2</sup>) 31.8±6.1). They clinically presented with a mean TJC-68 of 7.6±7.0 and a mean SJC-66 of 0.4±1.2. CRP (normal &lt;5.0 mg/l) and ESR (normal &lt;20 mm/h) showed mean values of 7.2±9.2 mg/l and 19.1±14.5 mm/h. Five patients (21%) were positive for HLA B27. Mean sum scores for synovitis and tenosynovitis by MSUS were as follows: GS-synovitis 11.1±6.3, PD-synovitis 0.5±0.9, GS-tenosynovitis 0.8±1.7, PD-tenosynovitis 0.2±0.6. Six HS patients (24%) presented with PD positive enthesitis of at least one enthesis. Mean sum scores by FOI were as follows: PVM 10.2±9.0, p1 1.1±2.7, p2 12.2±11.8, p3 0.7±1.1. <h3>Conclusion:</h3> This is the first study that objectively investigates the prevalence of pSpA features such as peripheral arthritis and enthesitis in a monocenter HS cohort. All imaging scores presented elevated values, so that an association between HS and pSpA could be strongly assumed. <h3>REFERENCES:</h3> [1] Jemec GB. Clinical practice. Hidradenitis suppurativa. N Engl J Med 2012; 366: 158-64 [2] Richette P, Molto A, Viguier M, et al. Hidradenitis suppurativa associated with spondyloarthritis - results from a multicenter national prospective study. J Rheumatol. 2014;41(3):490-494. [3] Fauconier M, Reguiai Z, Barbe C, et al. Association between hidradenitis suppurativa and spondyloarthritis. Joint Bone Spine. 2017. pii: S1297-S1319X(17)30164-1. [4] Schneider-Burrus S, Witte-Händel E, Christou D, Rigoni B, Sabat R, Diederichs G. High Prevalence of Back Pain and Axial Spondyloarthropathy in Patients with Hidradenitis Suppurativa. Dermatology 2016;232:606–612. [5] Rondags A, van Straalen KR, Arends S, et al. High prevalence of clinical spondyloarthritis features in patients with hidradenitis suppurativa. J Am Acad Dermatol 2019 Feb;80(2):551-554.e1. <h3>Acknowledgements:</h3> This study was partially supported by Novartis Pharma GmbH. Novartis Pharma GmbH did not have any influence on the study design, data analysis, or writing of the abstract. <h3>Disclosure of Interests:</h3> Sarah Ohrndorf Novartis; Janssen; Mylan, Speakers' honoraria or travel expense reimbursements by: • AbbVie, Amgen, BMS, Galapagos, Janssen, Mylan, Novartis, UCB, Novartis; GSK; AbbVie, Jens Klotsche: None declared, Tereza Jakovljevicova: None declared, Gabriela Schmittat: None declared, Gerd R. Burmester: None declared, Gerhard Krönke: None declared, Georgios Kokolakis: None declared.