Swollen feet and ankles

What is foot and ankle swelling?

Foot and ankle swelling is usually oedema (fluid building up in the tissue under your skin), most often in the lower legs and ankles¹. If you press gently on the area for a few seconds and a dent stays, that's called pitting oedema¹. Note whether one foot or both are swollen, when it started and whether it's worse by the end of the day, and tell your podiatrist.

Swelling like this is very common and has many causes². Often the cause is harmless, such as sitting or standing for long periods, but it can also signal heart, liver or kidney disease, so finding the cause matters more than treating the swelling alone².

What can cause swollen feet and ankles?

The commonest cause is standing or sitting still for long periods¹. Others include salty food, being overweight, pregnancy, varicose veins, thyroid problems, and some medicines such as certain blood pressure tablets, hormones, antidepressants and steroids³. An injury such as a sprain, a bite, an infection or a blood clot can also cause swelling, as can heart, kidney or liver problems³.

A few clues help tell causes apart, though they overlap:

• One leg or both? One leg more often means a local problem such as infection or a clot. Both legs more often means a whole-body cause such as heart, kidney or liver disease⁴.
• How fast? Swelling within 72 hours is more often linked with a clot, cellulitis (a skin infection), an injury or a newly started medicine. Swelling that builds over days, weeks or months more often has a whole-body cause⁵.
• Tender or not? Cellulitis and clots are often tender; swelling from heart, kidney or liver disease usually isn't⁵.
• Lymphoedema (long-term swelling when the lymphatic system isn't draining properly) may be soft and pit early on, come and go, and be worse during the day⁶. It's usually non-pitting, without the skin darkening or eczema seen with vein-related swelling⁴.

How is the cause found?

A podiatrist starts with your story and an examination, which is enough to find the cause in most people⁷. They'll ask when it started, whether one or both sides are swollen, whether it eases overnight, and about injuries and every medicine you take, so a list helps. They'll compare both legs, checking for pitting, skin changes, varicose veins, sores and tenderness⁴⁵, and may check blood flow to your feet before suggesting compression⁵.

Only some people need tests⁷. If a heart, kidney, liver or thyroid cause is suspected, blood and urine tests and heart tests may be arranged⁸. An ultrasound scan is used when a clot or vein problem is possible⁵.

What helps first?

Keeping your ankles moving is described as the most important thing you can do to stop them swelling⁹. These simple steps can help too³:

• walk little and often rather than taking one long walk⁹;
• raise your legs on a chair or pillows when you can;
• wear wide, comfortable shoes with a low heel and soft sole, and avoid tight clothes or footwear;
• avoid long periods of standing or sitting;
• wash, dry and moisturise your feet.

After a recent ankle sprain, early exercise with a brace or tape works better than rest, ice, compression or elevation on their own, and better than a compression bandage¹⁰. This guidance comes from athletes, so it may not suit everyone. A podiatrist or physiotherapist can guide your exercises.

For swelling from weak leg veins, graded compression stockings are the main treatment⁴. They aren't safe if blood flow to the legs is poor, so have your circulation checked first⁵.

What helps if that isn't enough?

If swelling lasts despite self-care, ask for a review to confirm the cause rather than adding treatments yourself. Compression is described as effective for most causes of oedema⁸. In adults with long-term leg swelling and repeated cellulitis, it lowered the chance of cellulitis coming back¹¹. After a DVT (a blood clot in a deep vein), it eased symptoms in the first year but not after that¹². If lymphoedema is suspected or confirmed, referral to a lymphoedema service is recommended for learning to manage it and for treatment².

Compression needs care. It isn't suitable with poor circulation, a leg or foot infection or severe heart failure¹³¹⁴. Fit matters, and people with nerve damage or fragile skin need padding, low pressure and close checks¹³.

Will it go away, and can I stop it coming back?

It depends on the cause. Lymphoedema is long-term, and without treatment its swelling usually becomes more severe and persistent⁶. After a DVT, some people develop post-thrombotic syndrome (lasting leg problems after a clot), which can include venous ulcers¹⁵. After an ankle sprain, starting guided exercise early reduces repeat injuries¹⁰.

To lower the chance of swelling returning, keep active, move your ankles during long periods of sitting or standing, raise your legs when resting and wear wide, comfortable shoes. These steps are sensible, but it isn't clear yet how well they prevent swelling returning. Book a review if it returns or changes.