Swollen ankles can be a sign of conditions ranging from completely harmless to potentially serious. In most cases, the swelling results from fluid collecting in the tissues of your lower legs, pulled there by gravity after long periods of sitting or standing. But when the swelling is persistent, severe, or accompanied by other symptoms, it can point to problems with your heart, kidneys, liver, veins, or lymphatic system, or it can be a side effect of medication you’re already taking.
What matters most is the pattern: whether one ankle or both are swollen, how quickly it appeared, and what other symptoms came with it.
Heart, Kidney, and Liver Problems
When both ankles swell at roughly the same time, the cause is often systemic, meaning something is affecting your whole body rather than just your leg. Three major organ systems can drive this kind of swelling.
In congestive heart failure, one or both of the heart’s lower chambers stop pumping blood effectively. Blood backs up in the veins, and fluid gets pushed into the tissues of your legs, ankles, and feet. This swelling typically worsens throughout the day and improves overnight when you’re lying flat. It often comes with shortness of breath, fatigue, or a feeling of heaviness in the chest.
Kidney disease causes the body to retain fluid and salt that it would normally filter out. The resulting swelling tends to show up in the legs and around the eyes. A related condition called nephrotic syndrome damages the kidney’s tiny filtering vessels, causing protein to leak out of the blood. When protein levels drop, the body loses its ability to keep fluid inside blood vessels, and swelling follows.
Liver damage from cirrhosis triggers fluid buildup in the abdomen (known as ascites) and in the legs. If you notice ankle swelling alongside a distended belly, yellowing skin, or easy bruising, liver disease is a possibility worth investigating.
Chronic Venous Insufficiency
Your leg veins have one-way valves that keep blood flowing upward toward the heart. When those valves weaken or become damaged, gravity takes over and blood flows backward, a situation called venous reflux. The result is persistent swelling in your lower legs and ankles, especially after standing for a while or at the end of the day.
Over time, chronic venous insufficiency causes visible changes beyond swelling. You may notice varicose veins, flaking or itching skin on your legs and feet, and patches of reddish-brown discoloration. That discoloration happens because the elevated pressure in your veins causes tiny capillaries to burst, leaving iron deposits in the skin. Without treatment, the skin in these areas becomes fragile and easily damaged by even minor bumps or scratches. New varicose veins are worth mentioning to your doctor, since they signal blood flow problems that can worsen over time.
Lymphedema
Your lymphatic system drains excess fluid from tissues and returns it to your bloodstream. When this system is blocked or damaged, fluid accumulates and causes a distinct type of swelling called lymphedema. It can affect one or both legs.
Lymphedema feels and looks different from other types of swelling. Early on, the skin has a dough-like quality and you can press a dent into it. Over time, the tissue becomes thickened, firm, and fibrotic, and pressing no longer leaves an indentation. A hallmark sign is swelling across the top of the foot with squared-off toes, and an inability to pinch the skin over the second toe (known as the Kaposi-Stemmer sign). Unlike most other causes of ankle swelling, lymphedema is typically painless, described more as a heavy sensation in the limb.
Medication Side Effects
Ankle swelling is a well-known side effect of calcium channel blockers, a class of blood pressure medications that includes amlodipine, nifedipine, and diltiazem. The swelling is dose-related: at lower doses, it affects 1 to 15 percent of people taking these drugs, but at high doses used long-term, the incidence can exceed 80 percent.
Unlike swelling caused by fluid retention, this type happens because the medication causes fluid to shift out of your capillaries and into surrounding tissues. It’s not dangerous on its own, but it can be uncomfortable. If you’re taking a blood pressure medication and notice new ankle swelling, it’s worth discussing with your prescriber. Other drug classes that can cause similar swelling include certain diabetes medications, anti-inflammatory drugs, and some hormonal therapies.
Swelling in One Ankle Only
When only one ankle swells, the cause is more likely to be local rather than body-wide. The most important condition to rule out is a deep vein thrombosis (DVT), a blood clot in the leg. DVT typically causes swelling in one leg along with pain, warmth, and sometimes redness. It requires prompt medical evaluation because the clot can break loose and travel to the lungs.
Once a blood clot is ruled out, the most common explanation is far less alarming. About 40 percent of single-leg swelling cases turn out to be from a muscle strain, tear, or twisting injury. A smaller number (around 3 percent) are caused by cellulitis, a skin infection that brings warmth, redness, and sometimes fever alongside the swelling.
Pregnancy-Related Swelling
Some degree of ankle swelling is normal in the later months of pregnancy, driven by increased blood volume and the weight of the uterus pressing on pelvic veins. But sudden, severe swelling, particularly in both legs, the face, and the hands, can signal preeclampsia, a serious pregnancy complication.
The key distinguishing features of preeclampsia include blood pressure readings above 140/90 mmHg, severe headaches, blurry vision, upper abdominal pain (especially on the right side), and confusion. Protein in the urine has traditionally been used to confirm the diagnosis, though doctors now recognize that other abnormal lab findings or clinical signs can also confirm it. Normal pregnancy swelling tends to develop gradually and feel mild. Preeclampsia swelling worsens suddenly and severely.
How Doctors Assess Swelling Severity
When you visit a doctor for ankle swelling, they’ll likely press a finger into the swollen area and watch what happens. If the pressure leaves a temporary dent, it’s called pitting edema, and it’s graded on a 1-to-4 scale. Grade 1 leaves a shallow 2-millimeter pit that bounces back immediately. Grade 2 creates a 3- to 4-millimeter pit that rebounds in under 15 seconds. Grade 3 produces a 5- to 6-millimeter pit that takes up to a minute to refill. Grade 4, the most severe, leaves an 8-millimeter pit that can take two to three minutes to rebound. Higher grades generally prompt more urgent investigation into the underlying cause.
Managing Swelling at Home
Regardless of the cause, a few practical strategies help reduce fluid buildup in the ankles. Elevating your legs above heart level for 15 to 30 minutes several times a day lets gravity work in your favor. Reducing sodium intake makes a meaningful difference: the American Heart Association recommends staying under 1,500 mg per day for the general population, while guidelines for people with heart failure suggest keeping sodium between 2,000 and 3,000 mg daily, or under 2,000 mg for moderate to severe cases.
Compression stockings are one of the most effective tools for managing chronic swelling. Stockings rated at 15 to 20 mmHg of pressure have been shown in clinical trials to significantly improve edema and symptoms compared to lighter compression or none at all. For moderate swelling and varicose veins, stockings in the 18 to 30 mmHg range are commonly used. More severe edema or lymphedema may call for 30 to 40 mmHg or higher, though stronger compression should be fitted with guidance from a healthcare provider to ensure proper circulation.
Regular movement also helps. Walking activates the calf muscles, which act as a pump to push blood back up toward the heart. Even flexing your feet and ankles while seated can make a noticeable difference if your job keeps you in a chair for long stretches.
Symptoms That Need Emergency Attention
Most ankle swelling develops gradually and can be evaluated at a routine appointment. But certain symptom combinations require emergency care. Call 911 if swollen ankles are accompanied by chest pain, difficulty breathing, shortness of breath when lying flat, fainting, dizziness, or coughing up blood. These can indicate a blood clot in the lungs or a serious cardiac event.
Seek same-day medical attention if your leg swelling appears suddenly with no clear cause, follows a physical injury like a fall or accident, or occurs in just one leg with pain, pale skin, or coolness to the touch.