Oedema

Oedema is swelling caused by excess fluid trapped in the body’s tissues, most commonly affecting the feet, ankles, and legs, though it can occur anywhere in the body.

Table of contents

• What is oedema?
• Symptoms of oedema
• Causes of oedema
• Types of oedema
• When to seek medical help
• How oedema is diagnosed
• Treatment options
• Self-care and lifestyle changes

edema, fluid retention, water retention, dropsy, hydropsy

What is oedema?

Oedema is the medical term for swelling caused by fluid trapped in your body’s tissues^[1]. This condition occurs when excess fluid builds up in the spaces between cells, causing the affected area to increase in size. While oedema can affect any part of the body, it most commonly appears in the feet, ankles, and legs^[1].

The fluid between the spaces inside tissues and blood vessels is normally regulated by the pressure gradient across the tiny blood vessels (capillaries) and the protein concentration in the blood^[3]. When this balance is disrupted, fluid accumulates in the tissues, leading to noticeable swelling.

Oedema is common because there are many causes associated with the condition. Mild cases of oedema often go away on their own, while more severe cases may require medical treatment^[10].

Symptoms of oedema

The main symptom of oedema is swelling in your body. When a part of your body gets bigger due to fluid buildup in the tissues, you may notice several characteristic signs^[10].

Common symptoms include:

• Swelling or puffiness of the tissue right under the skin, especially in legs or arms^[1]
• Stretched or shiny skin over the swollen area^[1]
• Skin that holds a dimple (also known as pitting) after being pressed for a few seconds^[1]
• An area of your body that is larger than it was a day ago^[10]
• Feeling of leg heaviness or tightness in the swollen area^[1]
• Difficulty walking if your legs, ankles, or feet swell^[10]
• Stiffness in affected joints^[3]
• Weight gain over a few days or weeks^[2]

In some cases, the skin may not hold an indent when pressed, which is called non-pitting oedema^[3].

Causes of oedema

Oedema develops when the normal balance of fluids in your body is disrupted. There are many factors that can cause this imbalance, ranging from simple lifestyle factors to serious medical conditions^[1].

Common everyday causes include:

Standing or sitting in the same position for too long allows fluid to pool in the tissues of the lower legs due to gravity^[2]. This is particularly common after long flights or in people who have to stand for extended periods at work. Hot weather also makes the body less efficient at removing fluid from tissues^[3].

Eating too much salty food is another common cause. Salt (sodium) binds to water in your body and helps maintain fluid balance inside and outside your cells^[2]. When you consume foods high in salt, especially many packaged and processed foods, your body may retain water^[19].

Being overweight or pregnant can also lead to oedema. During pregnancy, hormones encourage the body to hold onto excess fluid, and the growing uterus puts pressure on blood vessels in the lower trunk^[10].

Medical conditions that can cause oedema:

Heart failure (also called congestive heart failure) occurs when the heart weakens and cannot pump blood effectively around the body^[6]. This causes blood to gather in front of the heart, and due to increased blood pressure in the veins, fluid seeps out into surrounding tissue, causing swelling in the legs or a buildup of fluid in the abdomen.

Kidney disease can cause oedema in the legs and around the eyes. When the kidneys do not remove enough sodium and water from the body, pressure builds up in the blood vessels, causing fluid to leak into tissues^[6].

Liver disease, particularly severe conditions like cirrhosis, causes the body to retain fluid. Cirrhosis also leads to low levels of proteins in the blood, which affects the body’s ability to keep fluid in blood vessels^[8].

Venous insufficiency occurs when weakened valves in the veins cannot efficiently push blood back up to the heart. Blood pools in the legs, forcing fluid out of blood vessels into surrounding tissue^[6].

Other medical causes include deep vein thrombosis (blood clot in the leg), problems with lymph nodes (lymphedema), allergic reactions, infections, and burns^[3].

Medications that can cause oedema:

Certain medicines are known to cause fluid retention as a side effect. These include some blood pressure medications, contraceptive pills, hormone therapy, antidepressants, steroids, and nonsteroidal anti-inflammatory drugs^[2].

Types of oedema

Oedema can be classified into different types based on where it occurs in the body and what causes it.

Peripheral oedema affects the feet, ankles, legs, hands, and arms. It is the most common type and usually results from problems with the circulatory system, lymph nodes, or kidneys. Symptoms include swelling, puffiness, and difficulty moving certain body parts^[8].

Pulmonary oedema occurs when excess fluid collects in the air sacs in the lungs, making breathing difficult^[3]. This is a serious condition that makes it hard to breathe, especially when lying down. You may have a fast heartbeat and cough up a foamy discharge, sometimes with blood. If this happens suddenly, it requires emergency medical attention^[8].

Cerebral oedema is a very serious condition in which fluid builds up in the brain. It can happen after a head injury, if a blood vessel gets blocked or bursts, or due to a tumour or allergic reaction^[8].

Lymphedema is swelling in the arms and legs caused by damage to lymph nodes or lymph vessels. The damage may result from cancer treatments like surgery and radiation, or the cancer itself can block lymph nodes and lead to fluid buildup^[8]. This type of oedema is characterized by brawny, non-pitting skin^[14].

Macular oedema occurs when fluid builds up in the macula, which is the part of the eye that enables detailed, central vision. This is a serious complication of diabetic eye disease. People may notice changes to their central vision and how they see colors^[3].

When to seek medical help

While mild oedema often resolves on its own, there are situations when you should seek medical attention. Make an appointment to see a healthcare provider if swelling has not improved after treating it at home for a few days, or if it gets worse^[2].

Seek urgent medical care if:

• You have swelling in one ankle, foot, or leg with no obvious cause, such as an injury^[2]
• The swelling is severe, painful, or starts very suddenly^[2]
• The swollen area is red or feels hot to the touch^[2]
• Your temperature is very high, or you feel hot and shivery^[2]
• You have diabetes and your feet, ankles, or legs are swollen^[2]

Call emergency services (999 or 911) if:

• You feel short of breath or are struggling to breathe^[2]
• Your chest feels tight, heavy, or painful^[2]
• You are coughing up blood^[2]

These symptoms could indicate a blood clot in your lungs, which needs immediate treatment in hospital. Do not drive yourself to the hospital^[2].

How oedema is diagnosed

To diagnose oedema, a healthcare provider will perform a physical examination and ask about your medical history^[9]. During the exam, they will look for swelling, especially on parts of your body where your skin has a shiny or stretched appearance^[10].

Your provider will test your oedema by pressing their finger into the swollen area. This is called pitting, and it helps identify how much fluid is in your tissues. The severity of oedema is often described using a grading scale based on how deep the indent is and how long it takes for the skin to return to normal^[10].

In many cases, the physical examination and medical history are enough to determine the cause. However, additional tests may be needed, including:

• Blood tests to check for kidney, liver, or heart problems^[9]
• Ultrasound examinations to assess blood flow in the veins^[9]
• Urine tests to evaluate kidney function^[6]
• Chest X-ray or other imaging tests if lung or heart problems are suspected^[6]

Treatment options

Treatment for oedema depends on the underlying cause. Mild oedema usually goes away on its own without treatment^[9]. However, when oedema is caused by a medical condition, that condition needs treatment as well.

Compression garments: Wearing compression garments and raising the affected arm or leg higher than the heart helps reduce swelling^[9]. Compression stockings are particularly useful for leg oedema and should be put on in the morning before swelling gets worse^[2].

Diuretics (water pills): Medicines that help the body get rid of excess fluid through urine can treat more severe forms of oedema. One of the most common of these medications is furosemide^[9]. A healthcare provider will decide whether water pills are needed based on your specific situation.

Treating the underlying cause: The focus over time is often on treating the cause of the swelling. If oedema results from medication, for example, a healthcare provider might change the dose or look for another medicine that does not cause oedema^[9].

Lymphedema therapy: For oedema caused by lymphatic problems, specialized treatment may include manual lymph drainage, wrapping and massage, compression garments, skin care education, therapy exercises, and wound care^[11].

Self-care and lifestyle changes

There are several things you can do at home to help reduce mild oedema and prevent it from getting worse.

Movement and positioning:

Whenever you are resting, raise your legs up. Try to keep the swollen area higher than the level of your heart^[5]. Take breaks from standing or sitting in one position, and walk around to increase blood flow in your lower legs^[5]. Get some gentle exercise, like walking, to improve your blood flow^[2].

Move your feet and ankles often while you stand, or tighten and relax your leg muscles. These exercises not only build muscle but also help improve circulation, as the foot and calf muscles pump blood and fluid back up after periods of sitting or standing^[18].

Dietary changes:

Reduce your salt intake, as high sodium consumption triggers fluid retention in the body. Try cutting back on processed foods like fast food, which are typically high in salt^[5]. If you are cooking at home, flavor your food with herbs and spices instead of salt^[13].

Eat a balanced diet that includes fresh meat, fruits, and vegetables^[18]. If you are overweight, losing weight may help reduce oedema.

Hydration:

Drink plenty of water throughout the day. When you deprive yourself of water, your body stores it instead of excreting it through urine or sweat, which results in swelling^[13]. A well-hydrated body is less likely to retain fluid.

Choose plain water over coffee, tea, alcohol, juices, smoothies, and carbonated soft drinks, as these contain substances that can contribute to dehydration or fluid retention^[18].

Skin care:

Wash, dry, and moisturize your feet to avoid infections^[2]. Keep the swollen area clean, dry, and moisturized at all times^[13].

Other helpful measures:

Wear wide, comfortable shoes with a low heel and soft sole^[2]. Do not wear clothes, socks, or shoes that are too tight. Massage the area affected by oedema to help move fluid out of the tissues^[13].

Some people find that soaking their legs in a salt bath helps. Epsom salt can draw out toxins from your body and help with relaxation. Dissolve a cup of Epsom salt in a bathtub of lukewarm water and soak your legs for at least 20 minutes^[13].