Quantitative nailfold capillaroscopy findings in a population with connective tissue disease and in normal healthy controls

OBJECTIVE: To describe and quantify the morphological characteristics of nailfold capillaries that distinguish different forms of connective tissue disease from healthy controls. METHODS: A CCD video microscope with fibreoptic illumination and PC based image processing was used to visualise nailfold capillaries and to quantify findings in 23 patients with systemic sclerosis (SSc), 22 patients with systemic lupus erythematosus (SLE), 21 patients with undifferentiated connective tissue disease (UCTD), and 38 healthy controls. RESULTS: Capillary density was reduced in SSc (5.2 (SD 1.3) capillaries/mm) compared with other patient groups and controls. The average number of enlarged capillaries/finger was high in all disease groups (5.5-6.6) compared with controls (2). However, giant capillaries were most frequent in SSc (43%) and were not present in controls. Mild and moderate avascular areas were present in all groups (35%-68%), but severe avascularity was most frequent in SSc (44%) compared with other patients (18%-19%) and controls (0%). The greatest frequency of extensive haemorrhage was in SSc (35%). CONCLUSIONS: There is a range of abnormal capillary findings in patients with connective tissue disease and healthy controls. However, certain abnormalities such as a reduced number of capillaries, severe avascularity, giant capillaries, and haemorrhage are most commonly associated with SSc. Videomicroscopy with image processing offers many technical advantages that can be exploited in further studies of nailfold capillaries.