Pitting edema is the term used to describe edema when pressure applied to the skin of the swollen area is released and an indentation is left behind (e.g. when the skin is pressed with a finger or when stockings or socks induce indentation). Causes Standing or sitting for long periods of time particularly in hot weather cancause excess fluid to accumulate in feet, ankles and lower legs. Low protein levels in the blood caused by malnutrition, kidney and liver disease can also cause edema. ... Swelling is often most visible in the feet and ankles.