Clinical characteristics of childhood-onset primary Sjögren’s syndrome in South Korea: a retrospective analysis

Background Sjögren’s syndrome is a chronic autoimmune disease involving the exocrine glands that rarely occurs in children and adolescents. As exocrine gland invasions, such as dry eye or mouth, decrease quality of life and increase the risk of malignancy in long-term outcomes, regular follow-up is necessary. We aimed to identify the clinical features of primary childhood Sjögren’s syndrome in South Korea to facilitate diagnosis and treatment. Methods We retrospectively analyzed childhood-onset primary Sjögren’s syndrome in patients aged < 20 years from 2008 to 2024. Data from patients who visited Seoul National University Children’s Hospital and Pusan National University Children’s Hospital were collected from electronic medical records. Results Twenty patients (five males and 15 females) exhibited a sex ratio of 1:3. The age at diagnosis was 14.2 ± 2.5 years, and the age at last follow-up was 18.3 ± 4.0 years. Among symptoms at diagnosis, systemic involvement (such as fever) was the most common (75%), followed by parotitis or a previous history of parotitis (45%), and dry mouth, musculoskeletal involvement, and skin involvement (40%). Parotitis was prevalent in the early-onset group, whereas xerophthalmia was more common in the late-onset group. Pharmacological treatment was administered to 85% of patients, with hydroxychloroquine and corticosteroids being the primary medications. Improvements in inflammatory marker levels and European League Against Rheumatism Sjögren’s Syndrome Disease Activity Index (ESSDAI) scores were observed at the last follow-up. Cutaneous involvement was identified as the most significant prognostic factor for a higher final ESSDAI score in multivariate regression analysis (β = 4.784). One patient was diagnosed with dermatofibrosarcoma during follow-up. Conclusions The clinical symptoms of childhood-onset primary Sjögren’s syndrome differ from those in adulthood. Even if they do not initially meet the diagnostic criteria, regular follow-up is necessary, and appropriate treatment should be provided. Additional multicenter studies are needed to understand the characteristics of childhood-onset primary Sjögren’s syndrome.