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Managing Cancer Care

Edema (Swelling)

Cancer and cancer treatment can cause different types of swelling. It might be called edema or swelling, depending on where it is and what is causing it.

What is edema?

Edema is the medical word for when there is a build-up of fluid somewhere in the body. Fluid leaks out from blood vessels called capillaries and into the nearby tissues. Edema can develop suddenly or slowly over time.

Types and causes of edema

The most common type of edema is peripheral edema. It refers to swelling in the arms, legs, hands, or feet. It can be caused by conditions such as heart failure, kidney disease, or poor circulation.

Other causes of edema include:

  • Certain medicines such as steroids, which can cause fluid retention and edema as a side effect.
  • A tumor, blood clot, or something else blocking or damaging a blood vessel
  • Heart, lung, liver, and kidney problems, which can cause fluid to back up
  • Allergic reactions to medicines, which can cause swelling and edema, especially around the face, lips, and throat

Edema may be described as pitting or non-pitting, based on how the swelling reacts when you press on it. Knowing whether edema is pitting or non-pitting can help your health care team know what might be causing it and how best to treat it.

  • Pitting edema is often caused by too much water related to medications or conditions related to the heart, kidney, or liver. If you press a finger onto the area of edema and there is an indent (or a “pit”) left when you remove your finger, it’s pitting edema.
  • Non-pitting edema is most commonly caused by conditions that affect the thyroid or lymph system. Non-pitting edema is usually harder to treat than pitting edema because the trapped fluids contain more salt and proteins.

The information here focuses on peripheral edema, but there are other types of edema, including:

  • Lymphedema – a build-up of lymph fluid in certain areas of the body. It can develop after surgery or radiation that removes or damages lymph nodes. (See Lymphedema.)
  • Ascites  fluid in the abdomen (belly). It’s most commonly seen in cancers and disorders that affect the liver. (See Ascites.)
  • Pulmonary edema a build-up of fluid in the lungs. It’s most commonly caused by heart failure, severe infection, and sepsis.
  • Cerebral edema – too much fluid in the brain. In people with cancer, brain tumors are the most common cause of cerebral edema.
  • Anasarca a build-up of fluid all over the body.

What are symptoms of edema?

Sometimes edema is referred to as swelling. Swelling is the most common symptom of edema and develops when too much fluid causes a part of the body to look bigger and puffier.

Other symptoms include:

  • Fast weight gain
  • Feeling fullness, tightness, soreness, or discomfort in the swollen area
  • Clothing and jewelry feeling tighter than normal
  • Shiny or stretched skin
  • Difficulty moving or bending the affected area
  • Difficulty breathing, especially when lying down

Call 911 or go to the emergency department if you have:

  • Sudden or severe swelling, especially around the face or eyes
  • Difficulty breathing, especially when laying down
  • Chest pain or discomfort

These are signs of a possible allergic reaction or fluid in the lungs and require immediate medical attention.

Treatment for edema

It’s important to talk to your health care team if you have new or worse swelling. Edema that isn’t managed can lead to other problems such as infection and organ damage.

Some of the most common treatments for edema include:

  • Diuretics. If you have edema, you might also get medicines called diuretics (water pills) to help your body get rid of more fluid by making you pee more than usual.
  • Low-sodium diet. Your cancer care team might also suggest limiting sodium (salt) in your diet. Sodium makes your body hold onto more fluid.
  • Elevation. Gravity can make swelling worse. Propping the swollen area up can help reduce fluid buildup. 
  • Compression. Compression sleeves and stockings can be used for peripheral edema by helping move extra fluid back towards the center of the body.

When to talk to your doctor or cancer care team

If you have edema, talk to your doctor or cancer care team if you:

  • Have swelling, redness, or warmth in only one arm or leg
  • Gain several pounds in less than one week
  • Can’t pee for a day or more
  • Can’t eat for a day or more

Ask them what other symptoms you should call them for. Ask them who to call and when, including when the office or clinic is closed.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

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Last Revised: April 9, 2024

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