Dermoscopic detection of nail fold capillary abnormality in patients with systemic sclerosis

Abstract

The diagnosis of systemic sclerosis (SSc) is often difficult. The purpose of the present study was to find the distribution of nail fold capillary abnormality in SSc. Sixty-two patients with SSc (male : female = 7:55, age 21-86 years, mean 60.1) admitted to the outpatient clinics were studied. Eighteen age- and sex-matched normal subjects, 28 patients with systemic lupus erythematosus (SLE) and 10 with dermatomyositis (DM) were also studied. Nail fold capillary loops were observed under immersion oil at a magnification of ×40 with a light microscope. Dilated capillaries, nail fold bleeding and avascular areas were found by dermoscopic observation. The distribution of dilated capillaries, nail fold bleeding and avascular areas in normal controls showed in one (5.6%), one (5.6%) and four cases (22.2%), respectively. The distribution of dilated capillaries, nail fold bleeding and avascular area in SSc patients showed in 27 cases (43.5%), eight cases (12.9%) and 16 cases (25.8%), respectively. The distribution of dilated capillaries and/or nail fold bleeding in SSc patients (29/62, 46.8%) was significantly elevated than that of normal controls (2/18, 11.1%) (P < 0.01). The distribution of overall abnormality in SSc (30/62, 48.4%) showed no significant difference compared with that of normal controls (4/18, 22.2%). Sensitivity and specificity for dilated capillaries and/or nail fold bleeding and overall nail fold abnormality in SSc patients compared with normal controls was calculated as 40.8% and 93.5%, 34.8% and 88.2%, respectively. Dermoscopic observation of dilated capillaries and/or nail fold bleeding is a sensitive and specific method for the detection of SSc.