Blind evaluation of the diagnostic specificity of nailfold capillary microscopy in the connective tissue diseases.

Twenty-four patients with connective tissue diseases and 5 control subjects were studied by “widefield” photography. A total of 44 photographs of the nailfold were sent to the second author (HRM) for “blind” diagnostic interpretation. The scleroderma-dermatomyositis pattern was identified in 17 of 18 photographs of 11 scleroderma patients, and 5 of 5 photographs of 2 dermatomyositis patients. Six of 8 photographs of 5 patients with systemic lupus erythematosus were correctly identified, as were 7 of 7 photographs of 5 control subjects. These results demonstrate that characteristic patterns of nailfold capillary abnormalities can be identified and correlated blindly with the clinical diagnosis in several connective tissue diseases.