By Mayo Clinic Staff

Leg swelling can affect any part of the legs. This includes the feet, ankles, calves and thighs. Leg swelling may be the result of fluid that builds up. This is called fluid buildup or fluid retention. Leg swelling also may be the result of inflammation in damaged tissues or joints.

Leg swelling is often caused by common things that are easy to identify and are not serious. Injury and standing or sitting for a long time. Sometimes leg swelling indicates a more serious problem, such as heart disease or a blood clot.

Call 911 or seek medical care right away if you have unexplained leg swelling or pain, trouble breathing, or chest pain. These could be signs of a blood clot in your lungs or a heart condition.

Many factors can cause leg swelling. Some factors are more serious than others.

Leg swelling caused by fluid buildup in leg tissues is known as peripheral edema. It can be caused by a problem with how blood travels through the body. It also can be caused by a problem with the lymphatic system or the kidneys.

Leg swelling isn't always a sign of a heart or circulation problem. You can have swelling due to fluid buildup from being overweight, being inactive, sitting or standing for a long time, or wearing tight stockings or jeans.

Factors related to fluid buildup include:

• Acute kidney injury
• Cardiomyopathy (problem with the heart muscle)
• Chemotherapy
• Chronic kidney disease
• Chronic venous insufficiency (CVI). Leg veins have a problem returning blood to the heart
• Cirrhosis (scarring of the liver)
• Deep vein thrombosis (DVT)
• Heart failure — a condition in which the heart doesn't pump blood as well as it should
• Hormone therapy
• Lymphedema (blockage in the lymph system)
• Nephrotic syndrome (damage to small filtering blood vessels in the kidneys)
• Obesity
• Pain relievers, such as ibuprofen (Advil, Motrin IB) or naproxen (Aleve)
• Pericarditis (inflammation of the tissue around the heart)
• Pregnancy
• Prescription medications, including some used for diabetes and high blood pressure
• Pulmonary hypertension
• Sitting for a long time, such as during airline flights
• Standing for a long time
• Thrombophlebitis (a blood clot that usually occurs in the leg)

Leg swelling also can be caused by inflammation in leg joints or tissues. Swelling can be a response to injury or disease. It also may be the result of rheumatoid arthritis or another inflammatory disorder. You'll likely feel pain with inflammatory disorders.

Conditions that can cause inflammation in the leg include:

• Achilles tendon rupture
• ACL injury (tearing of the anterior cruciate ligament in your knee)
• Baker cyst
• Broken ankle
• Broken foot
• Broken leg
• Burns
• Cellulitis (a skin infection)
• Knee bursitis (inflammation of fluid-filled sacs in the knee joint)
• Osteoarthritis
• Rheumatoid arthritis
• Sprained ankle

Seek help if you have leg swelling and any of the following signs. They may be a sign of a blood clot in your lungs or a serious heart condition:

• Chest pain.
• Difficulty breathing.
• Shortness of breath with activity or lying flat in bed.
• Fainting or dizziness.
• Coughing blood.

Get care right away if your leg swelling:

• Happens suddenly and for no clear reason.
• Is related to a physical injury. This includes a fall, sports injury or car accident.
• Happens in one leg. The swelling may be painful, or your skin may feel cool and look pale.

Some problems related to leg swelling may not be an emergency. But they still need medical attention. Leg swelling that is the side effect of a medicine can look just like leg swelling caused by a kidney disorder. Make an appointment as soon as possible so that your health care professional can diagnose the cause.

Before your appointment, consider the following tips:

• Limit the amount of salt in your diet.
• Put a pillow under your legs when lying down. This may reduce swelling related to the buildup of fluid.
• Wear elastic compression stockings. Avoid stockings that are tight around the top. If you can see the imprint of the elastic on your skin, the stockings may be too tight.
• If you need to stand or sit for long periods, give yourself frequent breaks. Move around, unless the movement causes pain.
• Don't stop taking a prescription medicine without talking to your healthcare professional, even if you suspect it may be causing leg swelling.
• Over-the-counter acetaminophen (Tylenol, others) might ease pain from the swelling.