Swollen ankles and swollen feet are common and usually not cause for concern, particularly if you have been standing or walking a lot. But feet and ankles that stay swollen or are accompanied by other symptoms could signal a serious health problem. WebMD looks at some possible causes of foot and ankle swelling and offers advice on when to call the doctor.

Pregnancy complications. Some swelling of the ankles and feet is normal during pregnancy. Sudden or excessive swelling, however, may be a sign of preeclampsia, a serious condition in which high blood pressure and protein in the urine develop after the 20th week of pregnancy. If you experience severe swelling or swelling accompanied by other symptoms such as abdominal pain, headaches, infrequent urination, nausea and vomiting, or vision changes, call your doctor immediately.

Foot or ankle injury. An injury to the foot or ankle can lead to swelling. The most common is a sprained ankle, which occurs when an injury or misstep causes the ligaments that hold the ankle in place to be stretched beyond their normal range. To reduce the swelling from a foot or ankle injury, rest to avoid walking on the injured ankle or foot, use ice packs, wrap the foot or ankle with compression bandage, and elevate the foot on a stool or pillow. If swelling and pain is severe or doesn’t improve with home treatment, see your doctor.

Lymphedema. This is a collection of lymphatic fluid in the tissues that can develop because of the absence of or problems with the lymph vessels or after the removal of lymph nodes. Lymph is a protein-rich fluid that normally travels along an extensive network of vessels and capillaries. It is filtered through the lymph nodes, which trap and destroy unwanted substances, such as bacteria. When there is a problem with the vessels or lymph nodes, however, the fluid’s movement can be blocked. Untreated, lymph buildup can impair wound healing and lead to infection and deformity. Lymphedema is common following radiation therapy or removal of the lymph nodes in patients with cancer. If you have undergone cancer treatment and experience swelling, see your doctor right away.