Capillaroscopy.

Capillaroscopy is the most reliable way to distinguish between primary and secondary Raynaud's phenomenon (RP) through identification of an early pattern of systemic sclerosis (SSc). The presence of giant capillaries and microhaemorrhages on nailfold videocapillaroscopy (NVC) is sufficient to identify the scleroderma pattern (early), and an increase in these features and the addition of loss of capillaries (active pattern) is followed by neo-angiogenesis, fibrosis and 'desertification' (late pattern). The sensitivity of the American College of Rheumatology's classification criteria for SSc increases from 67% to 99% with the addition of these specific NVC abnormalities. Based on the appearance of the scleroderma pattern on NVC, almost 15% of patients shift from primary to secondary RP over a mean follow-up period of 29.4+/-10 months. Follow-up by NVC (every 6 months) is suggested for RP patients. A scoring system for NVC changes is available, and scores change significantly during follow-up of SSc patients. Several other NVC patterns have also been identified, such as in dermatomyosistis, systemic lupus eythaematosus, mixed connective tissue disease and antiphospholipid syndrome.