Common Causes of Foot and Ankle Swelling

Swelling in the ankles and feet is a common problem. A variety of things can cause it. One way that doctors pinpoint the cause of swelling is by noting whether it is occurring in one leg, or both equally.

This article will talk about why your ankles and feet may swell. It will discuss how medications, injuries, and medical conditions can influence swelling of the ankles and feet.

Common Causes of Foot and Ankle Swelling
Verywell / Ellen Lindner

Get Medical Attention for Sudden Swelling

In many cases, the cause of swelling is something that requires medical attention. For example, you could have an infection or injury. If the swelling occurs suddenly, seek medical care right away.

Some of the most common conditions that can cause foot or ankle swelling include the following:

  • Trauma
  • Arthritis
  • Vein problems
  • Blood clot
  • Infection
  • Pregnancy
  • Medical conditions
  • Medications

Trauma

The most common foot and ankle injuries that cause swelling include ankle sprains, torn tendons, and fractures. Overuse can lead to tendonitis, bursitis, and ligament or muscle strains.

These are all potential causes of swelling. And they are more likely to occur with sports, large amounts of exercise, or changes in the amount or type of activity. This includes walking or running on new terrain.

Arthritis

Arthritis, or joint inflammation, can cause swelling in the foot or ankle. Osteoarthritis is a common form of arthritis that may cause occasional swelling. It usually happens in a single joint. Gout is another form of arthritis that typically produces a very painful, red, swollen big toe joint. Gout can also affect the ankle.

Some autoimmune diseases cause swelling and arthritis that affect both feet equally, such as rheumatoid arthritis, psoriatic arthritis, lupus, and reactive arthritis. In each of these conditions, the immune system attacks healthy tissues, leading to pain, inflammation, and damage.

Vein Problems

Problems with leg veins, such as varicose veins or spider veins, often cause swelling in the lower legs. Veins return deoxygenated blood, or blood without oxygen, to the heart. As we age, they may become damaged. That's why we experience swelling of the legs and ankles.

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Things You Might Not Know About Varicose Veins

This is known as venous insufficiency. The most common signs are one leg that periodically swells (although both can be affected), varicose or spider veins on the leg or ankle, and a brown skin discoloration that can develop over time.

Blood Clot

Pain and swelling in the lower leg can also be signs of a blood clot. This is also known as deep vein thrombosis (DVT). DVT can lead to life-threatening complications and requires immediate medical attention.

DVT is often caused by inactivity. Some situations can make it difficult for you to move your legs frequently and may put you at risk for a DVT. These situations include:

  • Air travel
  • A leg cast
  • An illness requiring bed rest

Other risk factors include:

If you are a woman taking birth control medications, your risk of DVT is further increased if you also smoke or have an inherited blood clotting disorder known as Factor V Leiden.

Infection

Skin infection is a common cause of swelling. It's usually accompanied by pain and redness. Swelling is often seen with infected ingrown toenails (onychocryptosis), infections between toes, and severe forms of athlete's foot.

Other ways infection can occur in the feet include trauma, such as puncture wounds or nail injuries, and wounds caused by diabetes. Although much less common, an infection can occur in joints even without direct trauma.

Pregnancy

Swelling in both ankles and feet during pregnancy is a common occurrence. It is caused by a combination of pregnancy hormones, the increased volume of fluid being carried in the blood vessels, and the growing uterus. This places pressure on the veins that carry blood up from the legs.

Swelling in the legs can occur after giving birth as well. The swelling can last a few days after the delivery. Swelling during pregnancy should be discussed with your doctor or midwife.

If you suddenly begin to swell during pregnancy, you need immediate medical attention. It could mean you've developed preeclampsia, a dangerous type of high blood pressure that can occur during pregnancy.

Medical Conditions

Medical conditions that are known to cause swelling that affects both legs equally include:

Premenstrual syndrome (PMS) is also a well-known cause of swelling in the ankles and feet.

Medications

Some prescription medications can cause swelling that affects both legs equally. They include:

Drinking alcohol can also cause swelling in the ankles or feet.

Summary

Swelling of the ankles and feet is fairly common. You may experience this swelling for a variety of reasons. Sometimes swelling may occur because of trauma or an injury. You may have swollen ankles and feet because of arthritis or certain medical conditions.

Pregnant women may experience feet and ankle swelling as well. Other people may have swollen ankles and feet because of a blood clot or vein problems. For this reason, it's important to seek immediate medical attention if your ankles and feet suddenly begin to swell for no apparent reason.

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