Abstract
Systemic sclerosis is a complex disease that involves "autoimmunity," "inflammation," "fibrosis," and "vasculopathy." Microvascular damage and dysfunction particularly represent the earliest morphological and functional markers of systemic sclerosis. These morphological changes and progressions can be detected by nailfold videocapillaroscopy (NVC). In 2013, the American College of Rheumatology and European League Against Rheumatism (ACR/EULAR) proposed a new set of criteria for systemic sclerosis for the first time in 30 years. Items are given a weighted score, and a score more than 9 indicates systemic sclerosis. These classification criteria encompass a broader spectrum of systemic sclerosis patients including those with early stage and with excellent sensitivity and specificity. Notably, nailfold capillary abnormalities were one of the new items in the criteria. Moreover, these abnormalities are also markers of systemic sclerosis severity and progression, as reduced capillary density has been associated with a high risk of developing digital skin ulcers and pulmonary arterial hypertension. Since microvascular damage and dysfunction represent early markers of systemic sclerosis, qualitative and semi-quantitative assessment of videocapillaroscopy images is expected in clinical application and treatment outcome assessment. Despite the potential for targeted therapies in systemic sclerosis, there is no established therapy as yet. This may be due to several reasons. First, no fully validated outcome measures exist. Second, diagnosis of systemic sclerosis is often delayed and early intervention is difficult. Moreover, systemic sclerosis has clinical heterogeneity. Appropriate use of NVC helps to overcome these issues. Moreover, NVC may be useful in evaluating the pathogenesis of systemic sclerosis.