Causes
By Mayo Clinic staffA 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)
- Pregnancy
- 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
Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.
- O'Brien JG, et al. Information from your family doctor. What you should know about edema. American Family Physician. 2005;71:2118.
- Cho S, et al. Peripheral edema. American Journal of Medicine. 2002;113:580.
- O'Brien JG, et al. Treatment of edema. American Family Physician. 2005;71:2111.
- Treatment of pain and inflammation. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merck.com/mmpe/sec22/ch336/ch336e.html. Accessed March 1, 2009.
- Wilkinson JM (expert opinion). Mayo Clinic, Rochester, Minn. March 3, 2009.
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