Swollen lymph nodes in the armpit may indicate an infection, injury, or disease that requires medical attention. However, it’s usually not a sign of cancer.

Read on to learn what it means to have swollen lymph nodes in your armpit.

Lymph nodes are critical parts of the immune system. They filter foreign substances from the body and store white blood cells called lymphocytes. Lymphocytes fight disease and infections.

You have hundreds of small bean-shaped lymph nodes throughout the body, including in your:

  • neck
  • armpit
  • chest
  • abdomen
  • groin

A lymph node in the armpit that’s only slightly enlarged may be difficult to see, but you may be able to feel it with your fingers. A serious infection or other condition may cause one or more nodes to swell enough that you can see a lump under your skin.

Keep in mind that the armpit contains many nodes, so swelling could occur in the front, center, or back of the armpit, as well as along part of the upper arm near the armpit.

In addition to being swollen, an affected lymph node may also be sore or tender to the touch.

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CT scan showing swollen lymph nodes in armpit.
Ahn, R. W., Mootz, A. R., Brewington, C. C., & Abbara, S.
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Swollen lymph nodes in the armpit due to infection.
Casa nayafana/Shuuterstock
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Enlarged lymph nodes in the armpit due to tuberculosis.
Zay Nyi Nyi/Shutterstock

To check for a swollen lymph node in the armpit, lift your arm slightly and gently place your fingers into your armpit. Press your fingers against the center of the armpit and then around the front and back of the armpit along the chest wall. Do the same on the other side.

Lymph nodes exist in pairs on each side of the body, and typically only one node in a pair will be swollen. By comparing both sides, it may be a little easier to tell if one is enlarged.

If lymph nodes are swollen in more than one part of the body, the condition is known as generalized lymphadenopathy, which suggests a systemic illness. Localized lymphadenopathy refers to swollen lymph node(s) in one location.

The location of swollen lymph nodes usually suggests the cause of the problem. A swollen lymph node in the neck, for example, is often a sign of an upper respiratory infection.

When lymph nodes in the armpit become swollen, your body may be fighting a viral infection, or any of several other conditions. The potential causes of a swollen lymph node in the armpit can include:

Viral infection

Common viruses can trigger swelling in one or more lymph nodes in the armpit. They can include:

More serious viral infections that may cause lymph node enlargement include herpes, rubella, and HIV.

These viruses may also cause lymph nodes in the neck to become enlarged, too. In many cases, rest, fluids, and time are all that you can do while your immune system fights off the virus. For certain viral infections, like HIV, antiviral medications may be necessary.

Bacterial infection

Some common bacterial infections on the arm or surrounding chest wall, including staphylococcus and streptococcus, can lead to an enlarged lymph node in the armpit and elsewhere in the body. Antibiotics and rest are usually enough to overcome a bacterial infection.

Immune system disorder

Flare-ups of autoimmune disorders, like lupus and rheumatoid arthritis, can cause temporary enlargement of the lymph nodes in an armpit. Treatments vary, depending on the cause, but anti-inflammatory medications, pain relievers, and in serious cases, immunosuppressant drugs may be necessary.


Certain types of cancer directly involve the lymphatic system. Lymphoma actually originates in the lymph glands. Leukemia, a cancer of the blood cells, can cause inflammation and swelling of the lymph nodes.

Cancers that form in other organs or tissue may spread to the lymphatic system. Breast cancer, for example, can cause swelling of the lymph nodes in the armpit.

An enlarged lymph node near a cancerous tumor is often suspected of also being cancerous. Cancer treatments vary and may include chemotherapy, radiation therapy, surgery, and other approaches.


In rare cases, certain medications can cause lymph nodes to swell. Among them are:

  • ACE inhibitors, beta blockers, and vasodilators to treat high blood pressure
  • anticonvulsant drugs, including phenytoin and primidone
  • anti-malarial drugs, including quinidine
  • uric acid reducers, like allopurinol

Switching medications or adjusting doses may be enough to reduce side effects like lymph node enlargement.

As your body starts to successfully fight off the infection, the swelling in your lymph nodes should start to diminish.

With a typical bacterial infection, for example, a course of antibiotics should start to relieve lymph node swelling and other symptoms within a few days. A stubborn viral infection could take longer.

If your other symptoms are subsiding, but your lymph nodes remain swollen, tell a health professional. You may need additional treatment or a follow-up exam to see if there are other reasons your lymph nodes are still enlarged.

Because swollen lymph nodes are more often signs of an infection, rather than cancer, you may be inclined to dismiss swelling as a temporary symptom that’ll subside as you get over your infection. In many cases, that’s exactly what will happen.

If you’re unsure whether to seek a medical evaluation for swollen lymph nodes, these signs may be reasons to see a medical professional:

  • One or more lymph nodes are swollen for no obvious reason.
  • The swelling has lasted or gotten worse over a period of 2 or more weeks.
  • The affected node feels hard and immovable when you press on it.
  • The swollen lymph nodes aren’t painful.
  • You have swollen lymph nodes in separate areas, like the armpit and groin.
  • You have other symptoms, like:

Swollen lymph nodes typically get better once your illness has been treated or goes away on its own. To support your immune system as it responds to the infection or illness, you can rest and drink plenty of fluids. If you are prescribed medication, be sure to take it according to the prescribing doctor’s instructions.

If you feel discomfort or pain due to your swollen lymph node, you can try applying a warm compress to ease discomfort. Over-the-counter (OTC) pain medication, such as acetaminophen (Tylenol), may also help reduce pain.

If your pain gets worse or does not resolve, you may need to consult a doctor for additional treatment or testing.

Most of the time, a swollen lymph node means your body’s immune system is doing its job in responding to an infection or other health problem. That also means you’re dealing with an illness or injury that may require treatment.

If you’re battling a cold, for instance, and you notice slight swelling of a lymph node in your armpit, pay attention to it for a few days and see if the swelling goes down when you start feeling better.

Unexplained swelling or the presence of other serious symptoms should prompt a visit with a health professional for a more complete evaluation.