Leg swelling can occur in any part of the legs, including the feet, ankles, calves and thighs. Leg swelling can result either from fluid buildup (fluid retention) or from inflammation in injured or diseased tissues or joints. Many of the causes of leg swelling, such as an injury or prolonged standing or sitting, are easily identified. Sometimes leg swelling may be a sign of a more serious disorder, such as heart disease or a blood clot. Seek medical care right away when leg swelling occurs for no apparent reason or you also have difficulty breathing, chest pain or other warning signs of a blood clot in your lungs or a serious heart condition.

Causes
Foot, leg, and ankle swelling is common when the person also:
Is overweight
Has a blood clot in the leg
Is older
Has a leg infection
Has veins in the legs that cannot properly pump blood back to the heart

Injury or surgery involving the leg, ankle, or foot can also cause swelling. Swelling may also occur after pelvic surgery, especially for cancer. Long airplane flights or car rides, as well as standing for long periods of time, often lead to some swelling in the feet and ankles. Swelling may occur in women who take estrogen, or during parts of the menstrual cycle. Most women have some swelling during pregnancy. More severe swelling during pregnancy may be a sign of preeclampsia, a serious condition that includes high blood pressure and swelling. Swollen legs may be a sign of heart failure, kidney failure, or liver failure. In these conditions, there is too much fluid in the body.

Home Care
Some tips that may help reduce swelling:
Put your legs on pillows to raise them above your heart while lying down.
Exercise your legs. This helps pump fluid from your legs back to your heart.
Follow a low-salt diet, which may reduce fluid buildup and swelling.
Wear support stockings (sold at most drugstores and medical supply stores).
When traveling, take breaks often to stand up and move around.
Avoid wearing tight clothing or garters around your thighs.
Lose weight if you need to.