What Causes Swollen Ankles?

Swollen ankles — also called edema — happen when fluid builds up in the tissues around the joints. Sometimes the cause is simple, like standing or sitting for too long or eating too much salt. Other times it can signal a medical condition, such as congestive heart failure, liver damage, or kidney disease.

And though rare, causes like preeclampsia in pregnancy and deep vein thrombosis are medical emergencies that require immediate medical care.

Here are some of the most common explanations for swollen ankles, plus when it’s time to get them checked out.

1. You’ve Been Standing or Sitting Too Long

If you’ve been on your feet all day or stuck sitting for hours, your ankles may swell simply because gravity causes fluid to pool in your lower body, says Aly M. Fayed, MD, clinical assistant professor of orthopedics and rehabilitation at University of Iowa Health Care in North Liberty, Iowa.

To reduce swelling, try walking or flexing your feet, elevating your legs, and drinking plenty of water, according to Dr. Fayed. Compression socks can also boost circulation during travel or long days on your feet, he adds

2. You Twisted, Sprained, or Injured Your Ankle

A swollen ankle can be your body’s way of signaling trauma, even from a seemingly minor twist. The healing process can cause inflammation and fluid buildup around the injured area. Injury-related swelling is usually accompanied by pain, tenderness, bruising, or difficulty putting weight on the ankle — unlike swelling from fluid retention, which is typically painless and affects both ankles evenly.

“Follow the RICE method, which stands for rest, ice, compression, and elevation,” says Fayed. “If this doesn’t help, or if you can’t put weight on that ankle, you should have it checked out.”

Depending on the severity of the sprain, your doctor may recommend anti-inflammatory medication, physical therapy, crutches, or a brace.

3. You’re Pregnant

Pregnancy-related swelling in the ankles is common and can be normal, says Fayed. As the uterus expands, it can put pressure on the veins, making it harder for fluid to circulate. Hormonal changes also cause your body to retain more fluid, which can contribute to ankle swelling.

However, sudden or severe swelling, especially in the face or hands, can signal preeclampsia, a pregnancy complication that requires prompt medical care. If you’re pregnant and notice dramatic swelling or vision changes along with the swelling, contact your doctor right away.

To manage mild ankle swelling, try resting with your feet up, wearing compression stockings, and avoiding standing for long periods.

4. You’re Eating Too Much Salt

A salty meal can make your body temporarily retain water, which can accumulate in your lower legs and feet and cause swelling, says Rana Afifi, MD, associate professor of cardiothoracic and vascular surgery at UT Health Houston’s McGovern Medical School.

In addition to swelling, other signs that your salt intake may be too high include persistent thirst, bloating, headache, and high blood pressure, adds Dr. Afifi. “If you’re noticing these symptoms, make sure to speak with your doctor to prevent longer-term vascular complications,” she says.

Over time, a consistently high-sodium diet can worsen swelling and strain your heart and kidneys.

5. Your Medication Could Be to Blame

Certain medications can cause fluid retention and ankle swelling as a side effect, says Fayed. These may include the following:

If you notice new or worsening swelling after starting a medication, don’t stop it on your own — Fayed advises talking to your doctor. They may adjust your dose or switch you to an alternative.

6. You Could Have Lymphedema

Lymphedema occurs when the lymphatic system, which drains excess fluid from tissues, is blocked or damaged. This leads to chronic swelling, usually in the legs or arms.

This chronic disease can develop after surgery, radiation therapy, or infection, or it may be linked to congenital conditions. The swelling tends to be persistent and firm, and skin in the area may feel tight or thickened.

Although there’s no cure, treatment can help control symptoms. Doctors may recommend manual lymph drainage (a type of massage), compression garments, exercise, or physical therapy to improve circulation and reduce swelling, says Afifi.

7. You May Have a Vascular Issue

Swollen ankles can point to a vascular problem, which is a condition that affects how blood flows. When circulation slows or veins are damaged, fluid can pool in the tissues, leading to swelling, says Afifi.

According to Afifi, some of the most common vascular causes include the following:

Chronic venous insufficiency occurs when damaged valves in the leg veins prevent blood from flowing back to the heart. Fluid pools, leading to swelling, heaviness, aching, or skin discoloration.

Varicose veins are a milder form of venous insufficiency in which enlarged, twisted veins just under the skin cause aching, throbbing, or visible swelling.

Deep vein thrombosis is when a blood clot forms in a deep vein, usually in one leg, causing sudden swelling, pain, redness, and warmth. Afifi emphasizes that this is a medical emergency that needs prompt treatment.

Peripheral artery disease involves a buildup of plaque in the arteries and limits circulation to the legs. Though it doesn’t usually cause swelling, advanced cases can lead to tissue damage that can make the ankles swell.

“Treatment for vascular diseases varies by type, severity, and location, but every approach aims to improve circulation, prevent complications, and relieve symptoms,” says Afifi. Common recommendations include regular exercise, a balanced diet, compression socks, and quitting smoking.

8. You May Have an Infection

Ankle swelling sometimes signals an infection in the skin or tissues, especially if it’s accompanied by redness, warmth, pain, or fever, according to Fayed. This can happen after a wound, blister, or insect bite allows bacteria to enter.

“Warmth and redness can be a sign of infection and should be taken seriously,” says Fayed. Left untreated, infections like cellulitis can spread quickly and become dangerous.

If you suspect an infection, see a doctor as soon as possible, he says. Treatment typically involves antibiotics and rest until the inflammation subsides.

9. You Could Have an Underlying Condition

Persistent or unexplained ankle swelling can point to an underlying health issue, especially involving the heart, kidneys, or liver, says Fayed. These organs help regulate how your body circulates and retains fluid, so when something’s off, it can show up in your lower legs, according to Fayed.

Common causes include the following:

Heart Disease When the heart isn’t pumping efficiently (as in heart failure), fluid can back up in the veins. This can cause ankle swelling, shortness of breath, fatigue, or sudden weight gain. If swelling appears with these symptoms, get checked right away.

Kidney Disease The kidneys regulate fluid and salt balance. When they’re not functioning properly, excess fluid can build up in tissues, leading to swelling around the ankles, feet, or even the eyes.

Liver Disease Conditions such as cirrhosis reduce the liver’s ability to make proteins that keep fluid in the bloodstream, allowing it to leak into tissues. This can cause swelling in the ankles and abdomen.

Treatment depends on the cause of your symptoms, so visit your doctor to determine what’s best for you.

When to See a Doctor

Mild ankle swelling that goes away with rest or elevation is usually harmless. However, you should see a doctor if the swelling comes on suddenly, affects only one leg, or does not improve with rest or elevation, says Afifi.

Certain symptoms can also signal a more serious condition like a blood clot or heart issue, she adds. Afifi advises getting emergency care if you have these symptoms:

Shortness of breath

Chest pain

Skin discoloration

Open sores

Numbness

Pain

The Takeaway

Most swollen ankles aren’t serious, especially if they happen after standing or sitting for long periods or after eating salty foods. Rest, elevation, and compression can usually help reduce mild swelling.

Persistent or painful swelling deserves attention. It can signal issues like vascular disease, infection, or problems with the heart, kidneys, or liver, especially if the swelling affects only one leg or comes with other symptoms.

Seek medical care right away if swelling is sudden, severe, or paired with pain, redness, shortness of breath, or chest pain, which may point to a blood clot or heart issue.

Healthy habits can help prevent swelling. Stay active, limit sodium, wear supportive footwear, and check in with your doctor if swelling keeps coming back or you’re on medication that may cause it.