Microscopy of the nailfold capillaries has found increasing use in dermatology, rheumatology and angiology particularly as an important tool to distinguish between primary and secondary Raynaud disease. The best evidence is available in systemic sclerosis where specific capillaroscopic patterns have a high positive predictive value for the development of the disease. Conversely, a regular capillary pattern rules out systemic sclerosis with high degree of probability. PRINCE (prognostic index for nailfold capillaroscopic examination) was developed to identify patients at high risk of developing systemic sclerosis. CSURI (capillaroscopic skin ulcer risk index) should predict the risk of developing digital ulcers in patients with systemic sclerosis with high specificity and sensitivity.

As a consequence of recent results a pathologic capillary pattern was integrated by the EULAR Scleroderma Trials and Research Group (EUSTAR) in the diagnostic algorithm of the VEDOSS-Project (very early diagnosis of systemic sclerosis). Capillary patterns may correlate with visceral involvement and capillaroscopy thus has the potential as a screening tool to enable early diagnosis of organ involvement in systemic sclerosis.