Nailfold videocapillaroscopy in healthy children and adolescents: description of normal patterns

to describe normal patterns of nailfold videocapillaroscopy (NVC) in healthy children and adolescents; to quantify the relationship between age and capillary dimensions, intercapillary distance and number of capillaries/mm; to evaluate the inter and intraobserver concordance.

Cross-sectional study including 100 healthy participants aged 5 to 18 years. Capillary dimensions (capillary loop length, capillary width and intercapillary distance) and number of capillaries/mm were evaluated in 900 capillaries using stereomicroscope under 100x magnification. Intra and inter observer agreements were tested.

The capillary dimensions (mean ± SD) were: capillary loop length 278.6±60.3 μm, intercapillary distance 124.1±28.1 μm, capillary width 15.0±2.6 μm. Teenagers between 15 and 18 years had longer and more enlarged capillaries than the other age groups (p<0.001 and p=0.012 respectively). We also found a significant increase in the number of capillaries/mm with age (p<0.001). There was a positive correlation between age and number of capillaries/mm, capillary length, and capillary width (p<0.001, R=0.796; p<0.001, R=0.368; p=0.004, R=0.285, respectively). There was a good intra and interobserver concordance. Enlarged capillary and avascular areas were present in 11% and 10% of capillaries respectively. A weak negative correlation was found between the intercapillary distance and the number of capillaries/mm (p=0.05; R=-0.20).

There is a wide variability in the capillary morphology among healthy individuals. There was a positive correlation between age and number of capillaries/mm, capillary length, and capillary width. In addition, NVC has been shown to be a reproducible method.