Oedema (edema): what it is, causes, treatment and when to worry

Oedema is the medical term for swelling caused by fluid collecting in the tissues. Edema is the American spelling, and both mean the same. The NHS says oedema in the ankles, feet and legs is common and often goes away on its own, though you may need medical advice if you have other symptoms or do not know what is causing it.

Oedema is a sign rather than a disease in itself, because many different conditions and circumstances can lead to fluid build-up. That is why the cause, rather than the swelling alone, decides what treatment you need.

The NHS says swelling in the ankles, feet or legs should go away on its own, and gives simple things to try. Raise your legs or the swollen area on a chair or pillows when you can, get gentle exercise such as walking to improve blood flow, wear wide comfortable shoes with a low heel and soft sole, and wash, dry and moisturise your feet to avoid infections.

Avoid standing or sitting for long periods and avoid clothes, socks or shoes that are too tight. Treatment for swelling that does not go away depends on the cause, and your GP can help with the right treatment, including whether lifestyle changes could help.

For specific causes, treatment differs. NHS pages on heart failure and lymphoedema describe cause-specific management. In lymphoedema, which is a long-term condition caused by a problem with the lymphatic system, the NHS says there is no cure but symptoms can usually be controlled with compression garments, skin care, regular movement, a healthy diet and specialised massage.

The NHS says oedema in the ankles, feet and legs can affect one or both legs. You may see swollen or puffy ankles, feet or legs, and shiny or stretched skin. You may also notice changes in skin colour, dry skin, discomfort, stiffness, and dents that stay when you press on the skin.

The NHS says oedema is usually caused by standing or sitting in the same position for too long, eating too much salty food, being overweight, being pregnant, taking certain medicines (such as some blood pressure medicines, contraceptive pills, hormone therapy, antidepressants or steroids), varicose veins, or thyroid problems.

It can also be caused by an injury such as a strain or sprain, an insect bite or sting, problems with your kidneys, liver or heart, a blood clot, or an infection.

The NHS says to see a GP if both ankles, feet or legs are swollen and it has not improved after treating it at home for a few days, it gets worse, or you have a heart, kidney or leg vein condition.

Ask for an urgent GP appointment or get help from NHS 111 if you have swelling in 1 ankle, foot or leg and do not know the cause, a lot of swelling after an injury or swelling that is getting worse, swelling that is severe, painful or starts very suddenly, swelling in other areas such as the face or tummy, a red or hot swollen area, a very high temperature or feeling hot, cold or shivery, or if you have diabetes and your feet, ankles or legs are swollen.

Call 999 if you feel short of breath or struggle to breathe, your chest feels tight, heavy or painful, you are coughing up blood, you notice palpitations, or you feel lightheaded, faint, confused, sick or clammy, because you could have a blood clot in your lungs. The NHS says not to drive yourself to A&E.

The NHS says it is normal to get some swelling in pregnancy, particularly in the legs, ankles, feet and fingers, and that it is often worse at the end of the day and further into pregnancy. Swelling that comes on gradually is not usually harmful to you or your baby, but it can be uncomfortable.

It explains that the body is holding more water than usual and that the weight of the growing womb can affect blood flow in the legs. Suggested measures are avoiding standing for long periods, comfortable shoes and socks, resting with your feet up, and walking or foot exercises.

A sudden increase in swelling can be a sign of pre-eclampsia. The NHS says to call your midwife, GP or labour ward immediately if you have a sudden increase in swelling in your face, hands or feet, a very bad headache, vision problems, severe pain just below the ribs, heartburn that does not go away with antacids, feeling very unwell, or feeling or being sick.

Swelling can be a sign of problems with the heart, liver or kidneys. In heart failure, the NHS lists swelling in the feet, ankles, legs or tummy (or feeling bloated), breathlessness on everyday activity or lying down, tiredness, sudden weight gain and night-time coughing among the symptoms, and says it is important to get them checked.

If you have already been diagnosed with a condition affecting your heart, kidneys or leg veins and your legs are swollen, the NHS advises seeing your GP.

Most people start with a pharmacist or GP. A GP can help with the right treatment for the cause, and the NHS says to speak to your GP about whether lifestyle changes could help. Long-term swelling from lymphatic problems may be referred to a specialist lymphoedema treatment centre.

Private GP, cardiology and vascular services also assess leg swelling; the underlying approach is to find the cause. Whichever route you use, ask which medicines might be contributing before stopping anything.