Impairment of capillaries permeability and changes of microcirculation are associated with inflammatory arthritis. In order to demonstrate microvascular differences between psoriatic arthritis (PsA) and rheumatoid arthritis (RA) we analyzed capillaroscopic abnormalities such as megacapillaries, haemorrhages, ramifications, and avascular areas in patients affected by these two rheumatic disorders. Moreover to identify specific capillaroscopy patterns we analyzed the following parameters: venous limb diameter, arterial limb diameter, capillary loop diameter, amplitude of the capillary loop, linear density of capillaries (on 2 mm), and number of twisted capillaries (on 4 mm). Through a comparative morphometric analysis of capillaroscopy, our study demonstrated the presence of specific microvascular differences between PsA and RA providing an additional diagnostic tool for the differential diagnosis. We also suggest that capillaries structural abnormalities might reflect endothelial injury due to systemic inflammation during chronic arthritis.