Recurrent uveitis unveiling axial spondyloarthritis: is inflammatory back pain always the main road to diagnosis? A monocentric cohort.

Background: Nongranulomatous acute anterior uveitis (NG-AAU) is the most common extra-articular manifestation of spondyloarthritis (SpA) and may be a warning sign of previously undiagnosed axial SpA (ax-SpA). Objective: Given the known diagnostic delay of ax-SpA, this study aimed to determine the prevalence of previously undiagnosed ax-SpA among NG-AAU patients and to characterize the clinical features of ax-SpA identified through uveitis. Design: Cross-sectional study. Methods: This monocentric study included consecutive NG-AAU patients referred to a tertiary ophthalmologic center between August 2024 and August 2025. All patients underwent a comprehensive rheumatologic assessment, including human leukocyte antigen B27 (HLA-B27) testing and sacro-iliac joint magnetic resonance imaging (MRI). Ultrasound evaluation of entheses and symptomatic joints was also performed. SpA diagnosis was established by expert opinion based on clinical, laboratory, and imaging findings. Results: Among 68 NG-AAU patients, 38 without a previous rheumatic diagnosis were included. Sixteen (43.2%) received a new diagnosis of ax-SpA, and none with peripheral SpA. HLA-B27 positivity was more frequent in ax-SpA than in non-SpA patients (56% vs 33%). All ax-SpA patients reported prior episodes of back pain, although inflammatory back pain was present in only 56.3% at the time of evaluation. Mean Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores and symptom duration were significantly higher in ax-SpA patients ( Conclusion: Nearly half of NG-AAU patients had previously unrecognized ax-SpA, often presenting with mild or atypical axial symptoms. These findings highlight the importance of integrated ophthalmologic and rheumatologic evaluation to facilitate earlier ax-SpA diagnosis.