Pediatric Sjögren Disease: Clinical Features, Diagnostic Challenges, and Outcomes in a Single-Centre Romanian Case Series

<b>Background/Objectives</b>: Childhood-onset Sjögren disease (cSjD) is a rare autoimmune disorder with heterogeneous manifestations and ongoing diagnostic challenges, as there are no validated paediatric criteria. Our study aims to characterise the clinical, laboratory, and imaging features of children diagnosed with cSjD at a single Romanian paediatric rheumatology centre between 2015 and 2025 and contextualise these findings within the most recent literature. <b>Methods:</b> A retrospective review of 15 consecutive cSjD patients was conducted, including clinical features, autoantibodies, imaging, biopsy findings, treatment, and outcomes. <b>Results:</b> Our cohort showed a significant female predominance (80%) and a broad age range at disease onset (3-15 years). Extraglandular manifestations were more common at presentation than glandular phenotypes (53.3% vs. 40%). Lupus-like extraglandular presentations frequently led to initial misdiagnosis as childhood-onset systemic lupus erythematosus (SLE) in our cohort. Sicca symptoms were present at diagnosis in only 3 of 15 patients (20%) and developed later during follow-up in an additional 4 patients (26.7%). Notably, the cohort included novel findings, such as an unprecedented presentation with acute exudative pericarditis complicated by cardiac tamponade. Anti-SSA antibodies and salivary gland ultrasound abnormalities were highly prevalent (86.7% and 100%, respectively). Anti-SSB antibodies were detected in seven patients (46.7%), with titres showing more variability than those of anti-SSA, ranging from just above the positivity threshold to mildly elevated levels. The association with macro-creatine kinase type I was another distinctive feature of this series. Chronic musculoskeletal pain and dryness were our patients' most frequently reported symptoms at the last assessment, affecting up to 5/15 (33.3%) in each domain. One patient showed irreversible ocular damage during our study. <b>Conclusions</b>: Extraglandular presentations of cSjD are highly heterogeneous and diagnostically challenging, often occurring without glandular symptoms. Lupus-like systemic features-including facial vasculitic purpura, with or without arthralgia, and occasional pericarditis, as observed in our cohort-may contribute to frequent initial diagnostic misattribution to SLE. Early salivary gland ultrasonography, targeted autoantibody testing, and selective biopsy are essential for timely diagnosis, underscoring the urgent need for paediatric-specific validated classification criteria.