Quantification of the nail fold capillary abnormalities in systemic sclerosis and Raynaud's syndrome.

Measurements were made of capillary luminal diameters and capillary numbers in four groups: 19 normal controls 10 patients with 'idiopathic' Raynaud's disease, 12 patients with Raynaud's phenomenon with an underlying connective tissue disease other than systemic sclerosis, and 18 patients with systemic sclerosis. There was a significant reduction of capillary numbers in all three patient groups compared with the normal controls. Both the afferent and efferent luminal diameters were also increased in each patient group. Patients with Raynaud's phenomenon, either on its own or associated with connective tissue disease, gave results intermediate between normal controls and patients with systemic sclerosis. There were no significant correlations between either the reduction in capillary numbers or increase in luminal diameter with disease severity or duration in systemic sclerosis. It is unlikely that capillary microscopy will provide useful prognostic information for an individual patient with systemic sclerosis; its predictive value in Raynaud's disease must await the outcome of long term follow-up studies.