Foot edema is the collection of fluid in one or both feet that causes them to swell. Depending on the cause, the foot may be painful, and other parts of the body such as the ankles and calves may also be involved. Swelling may occur due to a condition directly in the feet, or may result from fluid buildup in the body settling in the feet due to gravity.
Injury
One very common cause of foot edema is injury directly to the foot. In response to injury, the blood vessels in the feet allow the fluid to leak out into the tissues, resulting in swelling. Additionally, injury to the leg or ankle may also cause the foot to swell. Foot swelling may occur relatively soon after the injury, or may occur a few days afterward when fluid is allowed to run down the leg to the foot. The most common reason for changes in the area of swelling is the pull of gravity when the body is upright. Thus, it is important to elevate the injured area to above the level of the heart for a few days after the injury, notes Cedars-Sinai.
Gout
Gout is a type of arthritis that causes sudden and often severe pain in affected joints. The Penn State Milton S. Hershey Medical Center reports that the most commonly affected joint is the big toe in the foot, but gout can also cause edema in other sites of the body, including the entire foot. Gout is caused by the buildup of uric acid crystals in the joints that cause pain, inflammation and swelling.
Pregnancy
MedlinePlus reports that foot edema can also occur as a result of changes in the body during pregnancy. If the edema in the feet, as well as ankles, is severe, it may be a sign of a dangerous condition called preeclampsia, another sign of which is very high blood pressure.
Problems With Other Organs
Underperforming organs, according to MedlinePlus, may also cause foot edema. The edema may be a sign that the heart, liver or lung is not functioning as they should, which results in the buildup of fluid in the body.
Medications
Foot edema may also be a side effect of certain medications, notes MedlinePlus. Taking hormone replacement bills or birth control pills, which contain the female sex hormone estrogen, may lead to a build up of fluid in the body that causes foot edema. Other drugs that cause foot edema include calcium channel blockers that are used to treat high blood pressure, steroids and certain drugs used to treat depression, including MAO inhibitors.
