Leg swelling can occur in any part of the legs, including the feet, ankles, calves or 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 prolonged standing or sitting or an injury, are relatively harmless in the long term, and your doctor often can easily identify the reason for the problem. Sometimes, however, leg swelling may be a sign of a more serious disorder, such as heart disease or a blood clot. It’s important to seek prompt diagnosis and treatment when leg swelling occurs for no apparent reason or is accompanied by apparently unrelated symptoms, such as breathing difficulties or chest pain.
A wide range of factors — varying greatly in seriousness — can cause leg swelling.
Causes related to trapped fluids
Leg swelling caused by the buildup of fluids in leg tissues is known as peripheral edema. Several body systems help maintain the appropriate balance of fluids, including the circulatory system, the lymphatic system and the kidneys. A problem with any one of these systems may contribute to the buildup of fluids. Gravity can also contribute to the accumulation of fluids in your lower limbs, particularly with prolonged standing or sitting.
Leg swelling due to trapped fluids can be caused by such factors as:
- Acute kidney failure
- Cardiomyopathy (disease of heart tissue)
- Chronic kidney failure
- Chronic venous insufficiency (problem with leg veins returning blood to the heart)
- Heart failure
- Hormone therapy
- Lymphedema (blockage of lymph system)
- Nephrotic syndrome (damage to small filtering blood vessels in the kidneys)
- Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil, Motrin, others)
- Pericarditis (swelling of the membrane surrounding the heart)
- Preeclampsia (pregnancy-induced high blood pressure)
- Prescription medications, including some drugs for depression, diabetes and high blood pressure
- Prolonged sitting, such as during airline flights
- Prolonged standing
- Thrombophlebitis (blood clot, usually in the leg)
Causes related to inflammation
Leg swelling may also be caused by an immune system response that leads to inflammation in leg tissues. Inflammation may be a normal response to injury or disease, or it may be the result of an inflammatory disorder, such as rheumatoid arthritis. Leg swelling related to inflammation is usually associated with pain.
Factors that can contribute to inflammation in the leg include:
- Achilles tendon rupture
- ACL injury (tearing of the anterior cruciate ligament in your knee)
- Baker’s cyst
- Broken ankle/broken foot
- Broken leg
- Gout (arthritis related to excess uric acid)
- Infection or wound in the leg
- Knee bursitis (inflammation of fluid-filled sacs in the knee joint)
- Osteoarthritis (disease causing the breakdown of joints)
- Rheumatoid arthritis (inflammatory joint disease)
- Sprained ankle
If you have leg swelling, it’s important to see a doctor for a thorough exam and accurate diagnosis.
Dial 911 or call for emergency medical assistance
Go to the emergency room or call 911 or your local emergency number if, in addition to leg swelling, you experience symptoms of a serious heart condition, including:
- Chest pain lasting more than a few minutes
- Difficulty breathing
- Fainting or dizziness
Also, seek immediate care if you know or suspect the swelling is related to a physical injury, such as a fall, sport injury or car accident.
Schedule a doctor’s visit
Nonemergency problems related to leg swelling still need prompt care. Leg swelling that is the side effect of a drug can look just like leg swelling caused by a kidney disorder. Make an appointment as soon as possible, so that your doctor can diagnose the underlying problem.
Before your appointment, consider the following tips:
- Put a pillow under your legs when lying down, which may lessen swelling related to the buildup of fluid.
- If you need to stand or sit for long periods, give yourself frequent breaks and move around, unless the movement causes pain.
- Don’t stop taking a prescription medication without talking to your doctor even if you suspect it may be causing leg swelling.
- Over-the-counter pain medication may lessen swelling associated with pain.