Nailfold capillaroscopy and laser Doppler flowmetry during standardised cold challenge to evaluate capillary pattern and digital flow in idiopathic acrocyanosis.

Quantitative correlation between capillary morphologic patterns and digital pulp flow in idiopathic acrocyanosis (IA) is as yet unexplained. We studied capillary pattern, scored according mainly to capillary dilatation and tortuosity. Digital flow was recorded by laser Doppler flowmetry during a standardised cooling and rewarming thermal challenge in a controlled thermostatic chamber. A negative correlation was found by linear regression analysis between increasing capillary abnormalities and decreasing flow rates both at rest and during cooling, while a positive correlation was observed among the presence and intensity of the flow stop reaction during cold challenge and the decrease of hyperaemic re-flow in the rewarming phase. Further investigations may be justified to assess the nature of these abnormalities, whether constitutional or induced by prolonged cold exposure. For this purpose, a standardised method, as the cooling-rewarming challenge, could verify the several pathophysiological hypotheses proposed for vascular acrosyndromes. We need to use a subjective method such as capillaroscopy-based scoring (as in our study endorsed by an objective technique) to acquire the necessary reliability and reproducibility in the functional diagnosis. In fact IA patients with lower morphologic scores show better flow properties.