Merck Manual

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Quick Facts



The Manual's Editorial Staff

Last full review/revision Sep 2019
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What is lymphedema?

Lymph is fluid that oozes out of your tiniest blood vessels. The fluid goes between your cells and brings nourishment and carries away damaged cells, cancer cells, and germs. Lymph then travels through tiny tubes called lymphatic vessels. The vessels carry lymph from your tissues to collection points called lymph nodes.

Edema means "swelling."

Lymphedema is swelling of an arm or leg because lymph flow is blocked.

  • Lymphedema usually results from having lymphatic vessels or lymph nodes removed or damaged (such as during surgery or radiation for cancer)

  • It can rarely result from a birth defect

  • Lymphedema has no cure, but special massages along with pressure stockings and bandages can help with the swelling

  • Doctors and nurses avoid drawing blood, taking blood pressure, or starting an IV in an arm or leg with lymphedema

What causes lymphedema?

Lymphedema results when part of your lymphatic system is blocked. Then, lymph builds up in your tissues, causing swelling. There are two types of causes.

Rarely, children are born without enough lymph vessels.

Usually, your lymph vessels are normal, but something happens that blocks them, such as:

In developing countries, a certain kind of worm infection called lymphatic filariasis causes lymphedema. Rarely, a cancer blocks your lymphatic vessels.

What are the symptoms of lymphedema?

One arm or leg swells up and looks puffy but has a normal color. It may feel tight, but it doesn't hurt. After you've had lymphedema for a while, the skin where the lymphedema is may be a darker brown color than your normal skin.

How can doctors tell if I have lymphedema?

Doctors can tell you have lymphedema by doing a physical exam. Usually, the cause is obvious, like surgery you've had. If doctors aren't sure why you have lymphedema, they may do imaging tests, such as CT scan or MRI, to locate a blockage in your lymphatic system.

How do doctors treat lymphedema?

Lymphedema has no cure. The following may help lessen your swelling:

  • Elevating the swollen limb to help the fluid drain (for example, keeping your foot up on a stool)

  • Special massages to help drain fluid

  • Arm or leg movements from your doctor to help move the fluid

  • Pressure bandages or stockings to wear on the swollen arm or leg

  • Rarely, surgery to remove the swollen tissues under the skin and to help lymph drain

It's important to avoid injuring an arm or leg with lymphedema. Also, if you have an arm with lymphedema, don't have your blood pressure taken on that arm or have blood drawn or an IV started. That could make your lymphedema worse.

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