What Causes Foot and Ankle Swelling?

Swelling in the ankles and feet is a common problem. Many things can cause it, including:

• Trauma
• Arthritis
• Vein problems
• Blood clots
• Infection
• Pregnancy
• Heart disease
• Medications

This swelling is often caused by a buildup of fluid, which is called edema. Edema is common in the feet, ankles, and legs.

This article can help you figure out what's causing your foot and ankle swelling.

Trauma

The most common foot and ankle injuries that cause swelling include:

• Ankle sprains
• Torn tendons
• Fractures (broken bones)

Those tend to be sudden injuries. Overuse can cause swelling as well, but these injuries tend to come on more gradually. Overuse injuries include:

• Tendonitis
• Bursitis
• Ligament or muscle strains

You're more likely to injure your feet or ankles if you play sports, exercise a lot, increase your activity level, or introduce a new exercise or activity, such as walking or running on a new type of terrain.

Trauma tends to happen to one foot or ankle at a time, so only one side will swell. Some accidents and overuse injuries may cause swelling in both.

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 joint. The big toe is most common but gout can also affect the ankle or other joints in the foot.

Some autoimmune diseases cause swelling and arthritis that affect both feet or ankles. These include:

• Rheumatoid arthritis
• Psoriatic arthritis
• Lupus
• 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 (blood without oxygen) to the heart. They may become damaged as we age and lead to swelling of the legs and ankles.

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 swollen leg or ankle
• A brown or darker brown skin discoloration that develops over time

Blood Clot

Pain and swelling in one lower leg can 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, such as:

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

Other risk factors include:

• Obesity
• Smoking
• Pregnancy
• Birth control medications
• Inherited blot clotting disorders

If you take 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 in one foot. It's usually accompanied by pain and redness. Swelling is often seen with:

• Infected ingrown toenails (onychocryptosis)
• Infections between toes
• 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 common. It's caused by a combination of:

• Pregnancy hormones
• Increased blood volume
• The growing uterus putting pressure on blood vessels in the legs

You may have swollen legs after giving birth, as well. The swelling can last for a few days after delivery.

If you have swelling during pregnancy, you should let your healthcare provider know.

Other Medical Conditions

Som medical conditions that can cause swelling in both legs include:

• Heart disease
• Kidney disease
• Liver disease
• Chronic sleep apnea
• Complications of diabetes
• Premenstrual syndrome (PMS)

Medications

Some prescription medications can cause swelling in both legs, as well. They include:

• Birth control pills
• Estrogen replacement drugs
• Testosterone drugs
• Corticosteroids
• Anti-inflammatory drugs (NSAIDs)
• Certain blood pressure medicines
• The diabetes drugs Avandia (rosiglitazone maleate) and Actos (pioglitazone)

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.