Fig. 1.

Nailfold videocapillaroscopic images of: (A) control (S.C.), showing a regular capillary array and density (mean capillaries 9.30 ± 0.53 per linear millimeter), with a majority of stereotype hairpin shaped capillaries and occasional crossing capillaries (B) primary Raynaud's phenomenon patient (E.S.), some nonspecific capillary dilations and crossing shapes are evident (mean capillaries 8.74 ± 0.68 per linear millimeter), (C) mild-moderate COVID-19 survivor (M.C.) with reduced number of capillaries and nonspecific abnormalities (tortuous and crossing capillaries) (mean capillaries 8.44 ± 0.75 per linear millimeter) and (D) severe COVID-19 survivor (G.G.) showing reduced number of capillaries, capillary ramifications and abnormal shaped capillaries (non-convex head) (mean capillaries 8.22 ± 1.15 per linear millimeter) (200× magnification). Horizontal bar is one millimeter long.