Diagnostic utility of nailfold capillaroscopy

Aim:  To determine the diagnostic utility of qualitative nailfold capillaroscopy (NC) in a clinical setting. Methods:  One hundred and sixty-seven patients, generally with Raynaud's phenomena of uncertain significance, were referred to an experienced operator for NC. NC was performed using low power wide field microscopy. Nailfold capillary arcades, number, calibre and presence of microbleeds were assessed on the third fourth and fifth nailfolds in each patient. Patients’ final diagnoses were determined by case note review following a mean of 6.6 years post-initial NC. Results:  Nailfold capillaroscopy was considered abnormal in 86/167 patients (51%), suspicious in eight, technically unsatisfactory in two and normal in the remainder. In those 86 patients with abnormal findings the follow-up diagnosis revealed scleroderma in 79, dermatomyositis in four and antisynthetase myositis in three. Three patients with suspicious findings also developed scleroderma. Of those 71 patients with initial normal NC only four were found to have developed scleroderma at follow-up. For a diagnosis of scleroderma NC demonstrated a sensitivity of 95%, a specificity of 91%, a positive predictive value of 92% and a negative predictive value of 94%. Nailfold capillary microbleeds were also frequently observed in patients with scleroderma, but were less specific than capillary morphological changes. Conclusion:  Qualitative NC performed by an experienced operator is considered to have high diagnostic utility in the early assessment of patients with Raynaud's phenomena, and when abnormal, is highly suggestive of scleroderma, dermatomyositis or antisynthetase myositis.