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.

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

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

  • neck
  • armpit
  • chest
  • abdomen
  • groin

Lymph nodes are typically 1 to 2 centimeters (cm) in size and lie deeper beneath the skin, making them hard to feel. Sometimes, you may be able to feel them if you’re very lean or if they become inflamed, such as due to infection.

Keep reading to learn more about how swollen armpit lymph nodes feel and look, and how to check for them.

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. Swelling may 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.

To check for a swollen lymph node in the armpit, lift your arm up slightly and place your fingers into your armpit.

Then, press your fingers against the center of the armpit and move them around the front and back of the armpit, along the chest wall. Do the same on the other side.

Lymph nodes exist in pairs, with one node on each side of the body. Typically, only one node in a pair is swollen. Comparing both sides may make it easier to tell if one is enlarged.

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

The United Kingdom’s National Health Service (NHS) recommends checking your lymph nodes once per month.

The location of swollen lymph nodes may suggest the cause of the problem. For example, a swollen lymph node in the neck is often a sign of an upper respiratory infection.

The potential causes of a swollen lymph node in the armpit may include the following:

Viral infection

Common viruses can trigger swelling in one or more lymph nodes in the armpit, including:

These viruses may also cause lymph nodes in the neck to become enlarged.

In many cases, rest, fluids, and time are all that you can do while your immune system fights off the virus. For more severe viral infections like HIV, antiviral medications may be necessary.

Bacterial infection

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 conditions like lupus, sarcoidosis, and rheumatoid arthritis may cause temporary lymph node swelling in the armpit.

Treatments vary, depending on the cause, but anti-inflammatory medications, pain relievers, and in serious cases, immunosuppressant drugs may be necessary.

Cancer

Certain types of cancer directly involve the lymphatic system. For instance, lymphoma actually originates in the lymph glands, while leukemia may cause inflammation and swelling of the lymph nodes.

Cancers that form in other organs or tissues may spread to the lymphatic system and other organs. This is known as metastatic cancer. For example, breast cancer 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.

Medications

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

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

The duration of swollen lymph nodes will depend on the underlying cause.

Swollen lymph nodes associated with an infection like the common cold may take 1 to 2 weeks to reduce in size.

With a typical bacterial infection, 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, consider speaking with a healthcare professional. They may wish to monitor your lymph nodes for 3 to 4 weeks to see if they get better on their own.

Swollen lymph nodes that last less than 2 weeks or remain the same size for more than 1 year are considered benign (noncancerous). A healthcare professional will usually perform several tests to confirm this.

Consider speaking with a doctor if you experience any of the following:

  • One or more lymph nodes are swollen for no obvious reason.
  • The swelling has lasted or worsened over a period of 1 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 the underlying cause is treated.

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 relievers, 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.

A cancerous lymph node in the armpit may feel hard when you touch it, and it will likely not move. On the other hand, a noncancerous lymph node may feel soft and rubbery and will move slightly.

Only a healthcare professional can determine the difference between a swollen lymph node and a lump or tumor using diagnostic tools, such as ultrasound and biopsy.

Yes, deodorant may cause swollen armpit lymph nodes if you have an allergy to the deodorant, or if you apply deodorant over an open wound and it becomes infected.

A swollen lymph node is usually a sign that your body’s immune system is responding to an infection or other health problem. This also means you may have an illness or injury that could require treatment.

If you’re managing 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.

If you experience unexplained swelling or the presence of other symptoms, speak with a healthcare professional. They could perform a more complete evaluation and, if necessary, develop an appropriate treatment plan.