aricose veins are swollen and twisted veins that usually occur in the legs. They are caused by weakened valves and veins in the legs that cause blood to pool in the veins instead of flowing back up to the heart. Varicose veins can be uncomfortable and cause aching, swelling, and skin changes. In severe cases, they may lead to more serious health problems. Treatment options include lifestyle changes, compression stockings, and minimally invasive procedures.