Office capillaroscopy in systemic sclerosis

Abstract

The aims of this study are to assess the reliability of two office techniques, the ophthalmoscope and the Dermlite dermatoscope, and to detect nailfold capillaroscopy abnormalities in systemic sclerosis (SSc). Two separate studies were performed. In the first, the nailfolds of two fingers on one hand of 13 SSc patients and two normals were examined by four rheumatologists using an ophthalmoscope. In the second, the nailfolds of the two fingers of each hand of six SSc patients and two normals were examined by six rheumatologists with a Dermlite dermatoscope. Widefield capillary microscopy was performed by one observer in the ophthalmoscope study to assess validity. The examiners determined the presence or absence of dilated loops, giant capillary loops, and/or avascular areas on each digit. The kappa coefficient was calculated to demonstrate agreement. With the ophtalmoscope, the inter-observer kappa coefficients were 0.43, 0.54, and 0.19; the average intra-observer agreements were 0.61, 0.56, and 0.31; and the ophthalmoscope-microscope agreement were 0.63, 0.52, and <0.1 for dilated capillaries, giant capillaries, and avascular areas, respectively. With the dermatoscope, the kappa values for inter-observer reliability were 0.63, 0.40, and 0.20; and intra-observer reliability was 0.71, 0.55, and 0.40 for dilated capillaries, giant capillaries, and avascular areas, respectively. The ophthalmoscope and the dermatoscope provide moderate to substantial reliability to detect the presence of giant and dilated capillaries but poor inter-observer agreement for avascular areas. The ophthalmoscope is valid when compared to the microscope for detecting giant or dilated capillaries. We conclude that these techniques are useful office tools to detect capillary abnormalities in SSc.