Swollen Feet, Ankles and Legs

Understanding oedema

What is oedema?

Oedema is swelling caused by fluid building up within the tissues.

It commonly affects the feet, ankles and lower legs, and may involve one leg or both.

Sometimes swelling is temporary and harmless, for example after sitting or standing for a long time. At other times, it can be a sign of an underlying problem involving the veins, lymphatic system, heart, kidneys, liver or another medical condition.

What does oedema look or feel like?

You may notice:

  • Swelling around the ankles or tops of the feet

  • Shoes or socks feeling tighter than usual

  • Sock marks around the lower leg

  • Skin that appears stretched or shiny

  • A heavy or aching sensation

  • Stiffness around the ankle

  • Changes in skin colour

  • Dry or uncomfortable skin

Sometimes pressing a finger into the swollen area leaves a temporary dent. This is known as pitting oedema.

However, not all swelling pits, and whether it does or does not pit does not by itself tell us what is causing it.

Why do feet and ankles swell?

There are many possible causes.

Common reasons include:

  • Sitting or standing in one position for a long time

  • Pregnancy

  • Varicose veins

  • Being overweight

  • Eating a high-salt diet

  • Certain medicines

  • Injury

  • Insect bites or stings

Some blood-pressure medicines, hormone treatments, contraceptive pills, antidepressants and steroids can contribute to swelling.

Oedema can also occur because of medical conditions affecting:

  • The veins

  • The lymphatic system

  • The heart

  • The kidneys

  • The liver

  • The thyroid

It can also occur with infection or a blood clot.

Is swelling in both legs different from swelling in one leg?

It can be.

Gradual swelling affecting both legs is commonly associated with things such as venous disease, medication, prolonged standing, reduced mobility or systemic medical conditions.

New unexplained swelling affecting only one leg deserves more urgent assessment because conditions such as a DVT, infection or injury need to be considered.

The NHS advises seeking urgent medical assessment for unexplained swelling affecting one ankle, foot or leg.

What is venous oedema?

The veins in the legs return blood back towards the heart.

If the valves within these veins become less effective, blood can pool within the lower limb and pressure increases within the veins. Fluid can then move into the surrounding tissues.

This is commonly associated with chronic venous insufficiency and may occur alongside:

  • Varicose veins

  • Aching or heavy legs

  • Swelling that becomes worse towards the end of the day

  • Brown pigmentation around the ankles

  • Itching or venous eczema

  • Skin thickening

  • Venous ulceration

We’ll definitely give chronic venous insufficiency its own information sheet, because there is a lot more to say about this.

What is lymphoedema?

Lymphoedema is swelling caused by a problem with the lymphatic system.

The lymphatic system helps remove excess fluid from the tissues. When drainage is impaired, fluid can accumulate and cause persistent swelling.

Early lymphoedema can be soft, may pit when pressed and can fluctuate during the day. Over time, it may become more persistent and the tissues may become firmer.

Again, lymphoedema deserves its own separate information sheet.

Can medication cause swollen ankles?

Yes.

Swelling may sometimes begin after a new medicine is started or the dose is changed.

This does not mean you should stop the medication yourself.

If you suspect a medicine is contributing to your swelling, speak to your GP or pharmacist. They can review whether the medication is likely to be involved and whether an alternative is appropriate.

What can I do to help mild swelling?

For mild swelling where there are no concerning symptoms, simple measures may help.

You can try:

  • Elevating your legs when resting

  • Taking regular gentle exercise such as walking

  • Moving your ankles regularly

  • Avoiding sitting or standing in one position for long periods

  • Wearing comfortable shoes

  • Avoiding socks, footwear or clothing that are excessively tight

  • Washing, drying and moisturising the skin regularly

These measures help movement of fluid and reduce skin complications.

Should I drink less water if my legs are swollen?

Usually, no.

It is understandable to think that drinking less will reduce fluid retention, but restricting fluids unnecessarily can lead to dehydration.

If you have been specifically given a fluid restriction because of a heart, kidney or other medical condition, follow the advice of the healthcare team managing you.

Otherwise, unexplained swelling should be assessed rather than self-treating it by drastically reducing fluid intake.

Should I take water tablets?

Not unless they have been prescribed for you.

Diuretics, sometimes called water tablets, are useful for certain medical causes of oedema but are not appropriate for every type of swelling.

For example, lymphoedema is not simply excess water in the body and is managed very differently.

Do not take someone else's diuretics or alter your prescribed dose without medical advice.

What about compression stockings?

Compression can be extremely helpful for some causes of lower-limb swelling.

It works by applying controlled pressure to the limb, helping blood and fluid move back up the leg.

However:

Compression is not automatically appropriate for everybody with swollen ankles.

The arterial blood supply to the leg needs to be considered, particularly before stronger compression is used.

NICE advises seeking expert opinion before fitting anti-embolism compression if arterial disease is suspected, and NHS lymphoedema guidance also notes that compression may not be suitable for some people with arterial problems.

So, rather than simply buying strong compression stockings because your ankles are swollen, it is sensible to understand why they are swollen and whether your circulation is suitable for compression.

Compression stockings and flight socks are not all the same

This is another useful distinction.

There are different types and strengths of compression products designed for different purposes, including:

  • Support hosiery

  • Medical compression hosiery

  • Anti-embolism stockings

  • Compression bandaging

  • Compression wraps

They are not interchangeable, and stronger compression should be selected according to the condition being treated and the person's vascular status.

When should I see my GP?

Arrange a GP assessment if swelling affecting both legs:

  • Does not improve after a few days of simple self-care

  • Is becoming progressively worse

  • Keeps recurring

  • Has no obvious cause

  • Occurs alongside known heart, kidney or venous disease

The underlying cause determines the appropriate treatment.

When is swelling more urgent?

Seek an urgent GP appointment or contact NHS 111 if:

  • One foot, ankle or leg suddenly becomes swollen without an obvious cause

  • Swelling is severe or painful

  • It develops very suddenly

  • The area becomes red or hot

  • You feel feverish, shivery or generally unwell

  • Swelling follows an injury and is significant or worsening

  • You develop swelling elsewhere, such as the face or abdomen

  • You have diabetes and develop new swelling of the feet, ankles or legs

These symptoms may need investigation for conditions including DVT, cellulitis, injury or other medical causes.

Call 999 immediately if swelling is accompanied by:

  • Shortness of breath or difficulty breathing

  • Chest pain or tightness

  • Coughing up blood

  • Fainting or feeling severely light-headed

  • Confusion

  • Cold, clammy skin or significant sudden illness

These symptoms can occur with a pulmonary embolism or another serious medical problem and require emergency assessment.

Swollen feet and ankles and your podiatry assessment

At Blackfords Footcare, swelling of the feet and lower legs is something we may identify during routine assessment.

Where appropriate, podiatric assessment can help evaluate:

  • The appearance and distribution of swelling

  • Skin condition and colour

  • Foot and ankle function

  • Arterial circulation

  • Foot pulses and Doppler findings

  • Whether wounds, pressure damage or infection are present

  • Whether footwear is contributing to discomfort or skin damage

Where compression is being considered, assessment of the arterial circulation may also be important to establish whether compression is appropriate.

However, we do not assume that unexplained swelling is simply a foot problem. If your presentation suggests an underlying vascular, cardiac, renal, lymphatic or other medical cause, we may recommend further assessment by your GP or another appropriate service.

A useful rule of thumb

Long-standing, symmetrical ankle swelling may need investigation.
New, unexplained swelling of one leg needs more urgent investigation.
Swelling with chest pain or breathlessness is an emergency.