"Edema, also known as fluid retention or swelling, is the buildup of fluid in the body's tissue. Most commonly, the legs or arms are affected.Symptoms may include skin which feels tight, the area may feel heavy, and affected joints may be hard to move. Other symptoms depend on the underlying cause.Causes may include venous insufficiency, heart failure, kidney problems, low protein levels, liver problems, deep vein thrombosis, infections, angioedema, certain medications, and lymphedema. It may also occur due to prolonged sitting or standing and during menstruation or pregnancy. The condition is more concerning if it starts suddenly, or pain or shortness of breath is present.