Armpit lump

Definition

An armpit lump is swelling of one or more lymph nodes under the arm.

Considerations

An armpit lump in a woman should be checked by a health care provider immediately, as it may be a sign of breast cancer.

Causes

Lumps in the armpit may have many causes. Lymph nodes are filters that can catch germs or cancerous tumor cells. When they do, lymph nodes increase in size and are easily felt.

Cysts and infections of the skin of the armpit may be caused by shaving or use of antiperspirants (not deodorants). This is most often seen in teens just beginning to shave.

Abscesses under the skin may also produce large, painful lumps in the armpit.

Other causes of armpit lumps may include:

• AIDS
• Arm or breast infection
• Cat scratch disease
• Cancers such as lymphoma or breast cancer
• Chickenpox
• Infectious mononucleosis
• Lipomas (harmless fatty growths)
• Normal breast tissue (breast tissue extends into the armpit area)
• Use of certain medicines or vaccinations
• Shingles (herpes zoster)

Home Care

Home care depends on the reason for the lump. Check with your health care provider to determine the cause.

When to Contact a Medical Professional

Call your doctor or nurse if you have any unexplained armpit lumps. Do not try to diagnose lumps without professional help.

What to Expect at Your Office Visit

Your doctor or nurse will examine you and ask questions about your medical history and symptom, such as:

• When did you first notice the lump?
• Is it getting better, worse, or staying the same?
• Are you breastfeeding?
• Have you noticed any factors that make it worse?
• What other symptoms are also present?
• Is the lump painful?

The physical examination may include gently pressing the nodes with the fingertips.

Testing depends on what is found during the physical examination.