Subclinical Spondyloarthritis Features in Patients with Hidradenitis Suppurativa: A Real-World Cross-Sectional...

The objective of this study is to investigate the frequency and clinical spectrum of subclinical spondyloarthritis (SpA) manifestations among patients with hidradenitis suppurativa (HS) and to evaluate their association with cutaneous disease severity and clinical characteristics.

In this prospective, cross-sectional real-world study, 120 adults with a confirmed diagnosis of HS were systematically assessed for musculoskeletal involvement. The evaluation included clinical examination for inflammatory back pain, peripheral arthritis, enthesitis, and targeted magnetic resonance imaging (MRI) for sacroiliitis when indicated. Laboratory analyses included C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and human leukocyte antigen B27 (HLA-B27) status. Spearman's rank correlation was used to analyze relationships between SpA-related features and HS clinical parameters, including the International Hidradenitis Suppurativa Severity Score System (IHS4) score, Hurley stage, and smoking.

Among the cohort, MRI-confirmed sacroiliitis was detected in 13.3%, enthesitis in 18.3%, HLA-B27 positivity in 12.5%, and peripheral arthritis in 10.0% of patients. A total of 12.5% fulfilled the modified New York criteria for ankylosing spondylitis. No statistically significant correlations were observed between SpA findings and HS severity indices. Weak associations were noted between smoking and both HLA-B27 positivity (ρ=0.27) and peripheral arthritis (ρ=0.21).

Subclinical axial and peripheral SpA features are frequently encountered in patients with HS, often in the absence of musculoskeletal complaints. The lack of correlation with skin disease activity highlights the need for routine rheumatologic evaluation in this population to enable early recognition and tailored treatment of inflammatory joint disease.