Legs
Swollen ankles
Swollen ankles and legs are usually caused by fluid building up in the tissues, which can range from a harmless effect of standing to a sign of a heart, kidney or vein problem.
Education and reference only. This explains the common causes of swollen ankles and the warning signs that need urgent help, in plain language — it is not a diagnosis or a substitute for advice from a clinician. If you feel very unwell or are worried, seek medical help.
Quick answer
What is swollen ankles?
Swelling in the ankles and lower legs, known medically as oedema, happens when fluid collects in the tissues. It is extremely common and often harmless, such as after long periods of standing or sitting, in hot weather, or during pregnancy.
- Get urgent help: One swollen, painful, red or warm calf or leg may be a deep vein thrombosis (blood clot) — seek urgent same-day assessment. Swelling with chest pain or breathlessness can point to heart failure or a clot that has travelled to the lungs — call 999.
- Self-care: For mild swelling linked to standing, sitting or warm weather, raising your legs above the level of your heart when resting can help fluid drain away.
About swollen ankles
Swelling in the ankles and lower legs, known medically as oedema, happens when fluid collects in the tissues. It is extremely common and often harmless, such as after long periods of standing or sitting, in hot weather, or during pregnancy. Swelling that affects both legs equally and eases when you put your feet up is usually less concerning. However, persistent or worsening swelling can be a sign that the heart, kidneys or veins are not working as well as they should. Swelling on only one side, especially if the leg is also painful, red or warm, raises the possibility of a blood clot and needs prompt attention. Sudden swelling of the face or lips alongside the legs can suggest an allergic reaction. Looking at whether one or both legs are affected, how quickly the swelling came on, and what other symptoms are present helps point to the cause.
When to get help
Call 999 or go to A&E if swollen ankles comes with any of these warning signs:
- One swollen, painful, red or warm calf or leg may be a deep vein thrombosis (blood clot) — seek urgent same-day assessment.
- Swelling with chest pain or breathlessness can point to heart failure or a clot that has travelled to the lungs — call 999.
- Sudden swelling of the face, lips or tongue, especially with difficulty breathing, can be a severe allergic reaction — call 999.
- Rapidly worsening swelling alongside feeling very unwell, faint or confused needs emergency assessment.
- A leg that becomes cold, pale or intensely painful needs urgent attention, as the blood supply may be affected.
When to see a doctor
See a doctor if swelling in your ankles or legs comes on without an obvious cause, does not settle after raising your legs overnight, or is getting steadily worse. Seek advice if the swelling is accompanied by breathlessness, tiredness, weight gain, or a reduction in how much urine you pass, as these can point to a heart or kidney problem that needs investigation. Persistent swelling of just one leg should always be checked. If you have a long-term condition such as heart, kidney or liver disease and notice new or worsening swelling, contact your doctor promptly.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
What can cause it
Common causes of swollen ankles
Swollen ankles has many possible causes. Each links to a full, plain-language guide to that condition — what it is, how it's treated and when to seek help.
What helps
Self-care and what you can do
For mild swelling linked to standing, sitting or warm weather, raising your legs above the level of your heart when resting can help fluid drain away. Moving around regularly, flexing your ankles and avoiding long unbroken periods of sitting or standing all encourage circulation. Gentle walking is helpful. Some people find well-fitted compression socks useful, but check with a pharmacist or doctor first, particularly if you have circulation or diabetes problems. Reducing the amount of salt in your diet may help if fluid retention is an issue. If swelling is persistent, getting worse, or accompanied by other symptoms, self-care is not enough and you should seek advice.
Answers
Swollen ankles: frequently asked questions
Why do my ankles swell more by the end of the day?
Gravity causes fluid to pool in the lower legs when you are upright for long periods. This kind of swelling usually eases overnight when you lie down. If it persists in the morning or worsens, see a doctor.
Is swelling in one leg more worrying than both?
Swelling in just one leg, particularly with pain, redness or warmth, can suggest a blood clot and should be assessed urgently. Swelling in both legs is more often linked to standing, the heart or the kidneys, but still warrants advice if persistent.
Can swollen ankles be a sign of heart problems?
Yes. When the heart pumps less effectively, fluid can build up in the legs. If swelling comes with breathlessness, tiredness or unexpected weight gain, see a doctor, as these together can indicate heart failure.
Do compression socks help with swollen legs?
They can help some people by supporting circulation, but they are not suitable for everyone, especially those with poor arterial circulation or diabetes. Ask a pharmacist or doctor before using them.
Sources
Where this is drawn from
- NICE CKS: Oedema.
- British Heart Foundation
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