Some patients have venous pressure high enough to cause backflow from the deep system into the superficial system via cross bridging veins known as perforators. In the limb with this condition, proteins and cells leak out from the circulation into the spaces between cells.
At the skin surface, this causes a stimulus for inflammation which recruits cells that further escalate the inflammatory process. The result is fibrosis of the skin and ulcer formation. The cycle of ulcer formation and healing followed by recurrent ulceration results in further thickening of the skin and areas of scarring known as atrophie blanche.