Cardiology Made Clearwith Dr. Freeman
All diagnoses

PATIENT EDUCATION · LEG, ANKLE & FOOT SWELLING

Swelling in the legs, ankles, or feet

Understand leg swelling, possible causes, warning signs, evaluation, and treatment.

Section 2 of 6 · Possible causes

← Swelling in the legs, ankles, or feet: the short explanation
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All 6 sections, including text and pictures · 12 pages

What should I do now?

Call 911

Call 911 for new or unexplained chest pressure that persists or returns, severe trouble breathing, collapse without normal recovery, or sudden face/arm weakness or trouble speaking. Do not drive yourself.

Contact your care team

Contact your care team promptly for increasing swelling, rapid weight change, or worsening breathlessness.

Keep your care plan

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

Patient summaries & logs →

SECTION 2

What can cause leg swelling?

Heart failure

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

Illustration of heart failure with reduced ejection fraction.
Heart failure is one possible cause. Fluid retention can also occur with preserved EF.
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An example of heart failure with preserved ejection fraction, showing thickened ventricular muscle and difficulty relaxing and filling.
HFpEF: the heart may squeeze normally but have difficulty relaxing and filling. This can raise pressures and contribute to swelling. Not every patient has thickened heart muscle.
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Venous insufficiency and lymphatic problems

Leg veins contain one-way valves that help blood return to the heart. When these valves do not close properly, blood can flow backward and pool in the legs. This is called venous insufficiency. Lymphatic drainage problems can also cause swelling.

Normal leg vein compared with leaky valves, backward blood flow, pooling, and ankle swelling.
Leaky leg vein valves allow backward flow and pooling, contributing to ankle swelling.
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Deep vein thrombosis (DVT)

A blood clot in a deep leg vein can block blood flow and cause swelling, often in one leg. Pain, warmth, or redness may occur. New one-sided swelling needs urgent assessment for a clot or another cause.

A blood clot obstructing a deep vein inside the calf, with reduced blood flow and possible swelling.
DVT: a clot in a deep leg vein can obstruct blood returning to the heart. Some clots cause swelling or pain; others cause no symptoms.
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Other causes

Kidney or liver disease, certain medicines such as amlodipine, injury, infection, or a blood clot may be responsible. Prolonged sitting or standing can contribute.

The pattern and accompanying symptoms guide assessment. A new one-sided change deserves particular attention.

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.