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PATIENT EDUCATION · THE SIMPLE EXPLANATION

Swelling in the legs, ankles, or feet, made clear.

A few pictures. Short explanations. Start here, then explore the full guide when you’re ready.

01 · SWELLING IN THE LEGS, ANKLES, OR FEET

Why are my ankles swollen?

Extra fluid in tissues is called edema. It may affect one leg or both. Causes include vein problems, medicines, and heart or kidney conditions.

The appearance alone does not tell us the cause.

02 · SWELLING IN THE LEGS, ANKLES, OR FEET

Can heart failure cause swelling?

Illustration of heart failure with reduced ejection fraction, showing an enlarged ventricle and weaker pumping.
Heart failure is one possible cause. Fluid retention can also occur with preserved EF.
Open full-size image →

Raised pressures and retained salt and water can cause swelling. Breathlessness, abdominal swelling, or weight gain may occur too.

03 · SWELLING IN THE LEGS, ANKLES, OR FEET

What can happen in the leg veins?

Leaky vein valves can let blood pool in the legs. A clot in a deep vein is a different problem that may cause new swelling or pain.

New one-sided swelling, pain, warmth, or redness needs prompt assessment. Chest pain or breathlessness with it is an emergency.

04 · SWELLING IN THE LEGS, ANKLES, OR FEET

How is the cause checked?

Your clinician reviews medicines, examines the swelling, and may order blood tests, a vein ultrasound, or a heart ultrasound. Treatment depends on the cause.

Track swelling and weight as instructed. Do not change a water pill without a specific plan.

Sources & further readingMedlinePlus: Leg and ankle swellingCleveland Clinic: Venous insufficiencyNHLBI: Deep vein thrombosis and blood clots

Updated October 2026. Educational information; your own care plan may differ. Medical illustrations are simplified examples for teaching.

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