Evaluation of nailfold videocapillaroscopy findings in juvenile idiopathic arthritis.

OBJECTIVE: Juvenile idiopathic arthritis (JIA) is the most common chronic inflammatory rheumatic disease in children. This study aimed to evaluate nailfold videocapillaroscopy (NVC) findings in children with JIA, compare NVC findings across JIA subtypes, and assess their relationship with disease activity. METHODS: This prospective cross-sectional study included patients diagnosed with JIA according to the International League of Associations for Rheumatology (ILAR) classification criteria who attended routine outpatient clinic visits between October 2025 and December 2025. NVC following the EULAR microcirculation protocol. NVC parameters were compared across JIA subtypes and against age-matched healthy reference data. RESULTS: The study included 104 patients (51.9% male), of whom 84 (80.8%) had a nonspecific pattern. None of the patients demonstrated a scleroderma pattern. Reduced capillary density was observed in 60.6% of the patients. Tortuous and crossing capillaries were present in all patients, while giant capillaries were not detected. Abnormal shapes, dilated capillaries, and microhaemorrhages were observed in 44.2%, 32.7%, and 25% of patients, respectively. Dilated capillaries were nominally more common in RF-negative polyarticular JIA (p = 0.045), though not after correction for multiple comparisons (q = 0.096). In comparisons with age-specific reference values, patients with JIA were found to have lower capillary density (p < 0.001), arterial (p < 0.001), venous (p < 0.001), and loop diameters (p < 0.001), capillary length (p = 0.003). No statistically significant correlations were observed between NVC parameters and disease duration or disease activity scores (p > 0.05). CONCLUSION: This study demonstrated significant microvascular differences in the NVC of children with JIA. However, largely similar NVC findings across JIA subtypes suggest subtype-specific differences are limited.