Many factors — varying greatly in seriousness — can cause leg swelling.
Leg swelling caused by the retention of fluid in leg tissues is known as peripheral edema. It can be caused by a problem with the circulatory system, the lymphatic system or the kidneys. You may also experience swelling due to fluid buildup after sitting or standing for a long time.
Leg swelling can also be caused by inflammation in leg tissues. Inflammation may be a normal response to injury or disease, or it may be due to rheumatoid arthritis or another inflammatory disorder. You will usually feel some pain with inflammation.
Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.