Oedema is a build-up of fluid in the body which causes the affected tissue to become swollen.
The swelling can occur in one particular part of the body or may be more general, depending on the cause.
Symptoms of oedema
The accumulation of fluid under the skin causes swelling, often in the lower legs and ankles (known as peripheral oedema).
As well as swelling or puffiness of the skin, oedema can also cause:
- skin discolouration
- areas of skin that temporarily hold the imprint of your finger when pressed (known as pitting oedema)
- aching, tender limbs
- stiff joints
- weight gain
Causes of oedema
It's normal to have some swelling in your legs at the end of the day, particularly if you've been sitting or standing for long periods.
Oedema is often a symptom of an underlying health condition.
It can occur as a result of the following conditions or treatments:
- pregnancy ↗
- kidney disease ↗
- heart failure ↗
- chronic lung disease ↗
- thyroid disease
- liver disease ↗
- malnutrition ↗
- medication, such as corticosteroids ↗ or medicine for high blood pressure ↗ (hypertension)
- the contraceptive pill ↗
Immobility and standing for long periods are the 2 most common causes of oedema in the legs.
Other possible causes include:
Oedema is often temporary and clears up by itself. For example, if you've been standing up for too long on a hot day, your ankles may swell up until you get the chance to put your feet up and rest.
If oedema doesn't go away by itself, see your GP. They'll try to find out if there's an underlying cause that needs to be treated.
This could involve taking medication or following some advice, such as:
- losing weight ↗ (if you're overweight)
- taking regular exercise ↗, such as walking ↗, swimming ↗ or cycling ↗
- raising your legs three to four times a day to improve your circulation
- avoiding standing for long periods of time
If an underlying condition is causing the fluid imbalance, it should clear up after the condition has been diagnosed and treated.
Lymphoedema is swelling in the legs caused by a blockage in the lymphatic system, or an inherited condition.
The lymphatic system consists of a series of lymph nodes (glands) connected by a network of vessels (lymphatics), similar to blood vessels.
Fluid surrounding body tissues usually drains into nearby lymph vessels so it can be transported back into the blood.
But if the lymph vessels are blocked, the fluid can't be reabsorbed and will build up in the tissue.
Unlike oedema, lymphoedema is a long-term condition that can cause discomfort, pain and a loss of mobility.
It can't be cured, but it can be controlled using a number of treatments.
- compression stockings ↗
- skin care
- lymphatic massage
Read more about lymphoedema ↗.
Other types of oedema
Other types of oedema include:
- cerebral oedema – a build-up of fluid that affects the brain
- pulmonary oedema – a build-up of fluid that affects the lungs
- macular oedema – a build-up of fluid that affects the eyes
These types of oedema have their own specific treatments.
Idiopathic oedema is a term used to describe cases of oedema where a cause can't be found.