Background: Capillaroscopy is an established tool to assess morphological and functional findings of the microcirculation which have a confirmed association with disease activity and damage of inflammatory rheumatic diseases, especially systemic sclerosis. Hairpin-shaped capillaries with normal density predict a very low risk for collagenosis.
Methods: Own databases were evaluated with respect to the topic of the manuscript and the current literature was evaluated.
Results: The healthy population does not only demonstrate hairpin shape as capillaroscopic normal findings and morphological and functional abnormalities can also be found which show various patterns depending on gender and age. These can be found in healthy persons and also patients with collagenosis. Ectasia and sludge phenomenon are more common in women and tortuous capillaries are more common in men. Capillary filling is often decreased in women and increased in male patients.
Conclusion: When assessing capillaroscopy findings, gender and the morphological or functional alterations which can be found in the normal healthy population should be taken into consideration. In further studies with capillaroscopy as the target parameter, the potential source of the disturbance should be known, especially in small populations, and if necessary balanced by weighted randomization.