Nailfold dermoscopy predicts the absence of a capillaroscopy sclerodermic pattern: The multicentre, prospective VASCUL-R trial.

Background: Nailfold capillaroscopy is recommended to diagnose primary or secondary Raynaud's phenomenon (RP). Capillaroscopy is normal in primary RP, which is the most frequent. Screening for RP capillary anomalies with nailfold dermoscopy has been promising.

Objective: To determine whether normal nailfold dermoscopy-based on the absence of five criteria that define a sclerodermic pattern-is able to predict normal capillaroscopy with good positive-predictive value (PPV).

Methods: Prospective, 2-phase (monocentre and multicentre) study on patients at first consultation for RP undergoing nailfold video capillaroscopy (NVC) and nailfold dermoscopy by two different 'blinded' trained observers, respectively, a vascular specialist and a dermatologist, not familiar with capillaroscopy. The five criteria noted were as follows: disorganization, megacapillaries, low capillary density, avascular areas and haemorrhages.

Results: Based on 105 patients, the dermoscopy PPV for a normal NVC was 100% (p = 0.015), with 37.9% sensitivity, when no criterion was observed. Excluding haemorrhages, the PPV remained 100% (p < 0.0001), with sensitivity rising to 73.7% and 100% specificity.

Conclusions: Normal nailfold dermoscopy with the absence of four easy-to-observe criteria predicts normal NVC with an excellent PPV.