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Swollen Lymph Nodes

(Swollen Glands; Lymphadenopathy)


The Manual's Editorial Staff

Reviewed/Revised Apr 2023
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What are swollen lymph nodes?

Lymph nodes are part of your lymphatic system Overview of the Lymphatic System The lymphatic system is a network of lymphatic vessels and lymph nodes that carry fluid called lymph. The lymphatic system is part of your immune system, which helps defend against infection... read more , which helps fight infection and cancer. Lymph nodes are pea-sized collection points that filter out germs and cells from lymph fluid. Lymph nodes are located throughout your body, but many are clustered in your neck, under your arms, and in your groin. They swell when your body has an infection or cancer.

  • The cause of the swelling is usually a nearby skin or tissue infection or a harmless virus that goes away on its own

  • Sometimes the cause is a more serious infection or cancer

  • Swollen lymph nodes may hurt, or they may be painless

  • Sometimes your doctor may do tests for certain infections or cancers

  • If the swelling in your lymph nodes doesn't go away in 3 or 4 weeks, doctors may do a biopsy (taking out part of the tissue to look at under a microscope)

People call swollen lymph nodes "swollen glands," but lymph nodes aren't really glands.

What causes swollen lymph nodes?

There are many causes of swollen lymph nodes. The most common causes are:

  • An infection in tissues near the swollen lymph nodes

  • Bodywide infection

More dangerous causes of swollen lymph nodes are:

Normally, your body's immune defenses kill any live germs that get into your lymph nodes. But sometimes a few germs survive and cause an infection. An infected lymph node hurts, and the skin over it turns red.

Cancer cells often break off from a cancer and travel through lymph vessels to nearby lymph nodes. For example, breast cancer often spreads to the lymph nodes in the armpit that's on the same side as the cancer. Sometimes your immune defenses kill the cancer cells. But sometimes the cancer cells grow in your lymph nodes. Cancer usually makes lymph nodes very hard and stuck together.

However, probably less than 1% of people with swollen lymph nodes have cancer.

When should I see a doctor?

Not every person with swollen lymph nodes needs to go to a doctor right away.

See your doctor right away if a lymph node is:

  • Very painful

  • Draining pus (thick, white or yellow fluid)

Call your doctor if you have any of these other warning signs:

The doctor will decide how quickly you need to be seen based on the warning signs and other symptoms.

If you have no warning signs and you feel well, you can wait a week to see if the node returns to normal before calling your doctor.

What will happen when I see the doctor?

How do doctors treat swollen lymph nodes?

Doctors treat the cause of your swollen lymph nodes.

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