Nailfold Capillary Microscopy in Adults with Inflammatory Myopathy

ObjectivesTo study the presence and characteristics of nailfold capillary changes in a cohort of adult patients with inflammatory myopathies, determine correlations with disease activity and severity, and investigate any relationship between capillary findings and the immunological or clinical characteristics of the groups.MethodsFifty-three consecutive adult patients followed in our outpatient clinic were evaluated using a Wild M3 stereomicroscope with an Intralux 5000 Volpi cold light lamp. A semiquantitative rating scale was used to score capillaroscopy changes. Disease activity and severity were assessed with the Myositis Disease Activity Assessment Tool and Myositis Damage Index, respectively. Associations between capillaroscopy findings and other factors were calculated with the χ2 and Mann–Whitney U tests. Serum autoantibody profile was determined in all patients.ResultsTwenty-three patients (43%) showed relevant capillaroscopy changes. No significant association was observed between the number of capillaroscopy alterations and the clinical or immunological groups, or disease duration. Disease activity and severity were both significantly associated with a larger number of capillaroscopy findings (P < 0.05). The combination of microhemorrhages and capillary enlargement was significantly more frequent in patients with dermatomyositis (OR, 8.9; 95% CI, 1.8-45.2), and a characteristic capillaroscopy pattern was associated with paraneoplastic myositis (OR, 14.7; 95% CI, 2.0-106.4). Interstitial lung disease significantly correlated with higher capillary score (OR, 3.7; 95% CI, 1.1-13.0).ConclusionsNailfold microcirculation as determined by semiquantitative simple capillaroscopy appears to provide useful information in patients with idiopathic inflammatory myopathy, contributing to an early diagnosis and identifying patients with a poor prognosis.