Use of nailfold capillaroscopy for evaluation of disease activity in juvenile dermatomyositis: Results of a two-center retrospective study.

BACKGROUND

Juvenile dermatomyositis (JDM) is a rare, immune-mediated children disease that affects both skeletal muscles and skin. Inflammatory vasculopathy is a key part of the JDM pathogenesis. Nailfold capillaroscopy (NFC) is a non-invasive method for microvasculature assessment. Despite the pathogenic relevance of microangiopathy in JDM, the diagnostic utility of NFC in JDM remains insufficiently defined.

AIM: To quantitatively assess capillaroscopic dynamics and their association with clinical and laboratory activity markers in JDM.

METHODS

This retrospective double-center cohort study included 52 children with confirmed JDM, who were followed at the clinics of Sechenov University and Saint Petersburg State Pediatric Medical University. Patients were divided into active and inactive JDM groups based on the modified disease activity score. Demographic, clinical, laboratory, and instrumental data were analyzed. NFC evaluation was performed using standardized criteria developed initially for adult patients with systemic sclerosis and Raynaud's phenomenon. Statistical analysis was conducted using Windows v.13 (StatSoft).

RESULTS

Active and inactive JDM groups were demographically comparable (predominantly female, median onset age 6 years). NFC revealed marked differences: Active patients showed higher rates of reduced capillary density (96.2% vs 60.9%, P = 0.003), giant capillaries (73.1% vs 13.0%, P < 0.001), perivascular edema (73.1% vs 17.4%, P < 0.001), and greater maximal apical loop width. Disease activity positively correlated with giant capillaries (r = 0.65), perivascular edema (r = 0.60), and reduced capillary density (r = 0.46). These findings confirm that specific NFC features are strongly associated with clinical disease activity, as measured by the disease activity score.

CONCLUSION

Children with active JDM demonstrated more frequent NFC changes, indicating that NFC may play a potential role in monitoring disease activity. Further studies are needed to determine the diagnostic accuracy and prognostic relevance of this approach.