Press "Enter" to skip to content

What Does a Lump Under Your Armpit Mean? Causes, Diagnosis, Treatment

Most lumps under the armpit are not dangerous. However, some bumps may signal a serious underlying condition, such as breast cancer or an infection.

An armpit lump or a swelling under the armpit (axilla) may result due to various reasons. 

Most causes of armpit lumps or bumps are not dangerous. However, you must consult a doctor for a definitive diagnosis. This is because some armpit lumps may be caused by serious underlying conditions.

A lump under the armpit is typically due to an enlarged lymph node (also called lymph glands or simply glands), which are spherical to oval structures present at various sites, such as the armpits, neck, chest, abdomen, and groin.

  • They are a part of the lymphatic system that plays a crucial role in the immune system.
  • Lymph nodes help fight infections by acting as filters that remove disease-causing organisms (including bacteria and viruses) from the lymph fluid that passes through them.
  • Hundreds of lymph nodes are present in different parts of the body, and they contain clusters of immune cells (lymphocytes) that help keep you healthy.
    • There are about 20 to 30 lymph nodes present in the armpit region.

Lymph nodes are generally too small to be felt under the skin. Swollen lymph nodes (called lymphadenopathy) in the armpit (axillary lymph nodes) can cause a lump that generally occurs due to an infection or allergy.

Other causes of a lump under the armpit

  • Infections, such as viral, fungal, and bacterial infections of the throat, respiratory organs, and breast, such as: 
    • Epstein–Barr virus infection,
    • cat scratch disease,
    • herpes,
    • human immunodeficiency virus infection,
    • tuberculosis, or
    • infectious mononucleosis or mono.
  • Autoimmune diseases, such as:
    • rheumatoid arthritis,
    • scleroderma,
    • psoriasis,
    • systemic lupus erythematosus,
    • dermatomyositis, and
    • Sjogren’s syndrome.
  • Cancers, such as:
    • leukemia,
    • lymphoma,
    • Kaposi sarcoma,
    • breast cancer,
    • lung cancer, and
    • skin cancer (melanoma).
  • Hidradenitis suppurativa (painful and swollen glands)
    • Typically seen in obese children that occur due to recurrent infections or abscesses of lymph nodes in the armpit.
  • Granulomatous diseases, such as sarcoidosis and silicone-induced granulomatous lymphadenitis
  • Post-vaccination lymphadenopathy, such as after bacille Calmette–Guérin vaccine
  • Lipoma (a lump of fatty tissue accumulated under the skin)
  • Folliculitis, which is a common skin problem where the hair follicles are infected by fungi or bacteria 
  • Sebaceous cyst
  • Fibroadenoma
  • Allergic reactions
  • Reaction to medications, such as:
    • allopurinol,
    • penicillin,
    • phenytoin,
    • hydralazine, and
    • sulfonamides
  • Diabetes mastopathy

How is a lump under the armpit diagnosed?

To know the cause of a lump or bump under the armpit, the doctor will do the following:

  • Take detailed medical history including:
    • The duration of the lump present
    • Associated symptoms (such as pain or fever)
    • Discharge from the lump, if any
    • Your current medications
    • Any underlying health conditions you may have, such as diabetes or human immunodeficiency virus infection
    • History of recent vaccination
    • History of cancer you or your family have
  • Do a thorough physical examination to know
    • The exact site of the lump
    • The size of the lump
    • Whether the lump is movable
    • Whether there is any discharge or redness
    • The condition of the skin
    • The number of enlarged lumps
    • Whether there are other lumps present
    • Any other relevant examination
  • Advise certain medical tests, such as:
    • Blood tests
    • Urine tests
    • Fine-needle aspiration cytology to examine the fluid from the lump
    • Imaging studies such as X-ray, computed tomography, and magnetic resonance imaging scans
    • Biopsy

How can I get rid of the lump under my armpit?

The treatment of an armpit lump or bump depends on its cause. You must contact your doctor for a definitive diagnosis and treatment.

  • In case of infections, the doctor may prescribe antibiotics, antiviral, or antifungal medications.
  • If the lump is caused by allergies, such as allergies toward a deodorant, your doctor may advise you to avoid the substance causing the allergy.
  • They may prescribe medications to manage symptoms, such as pain and swelling. 
  • Autoimmune diseases may be managed with appropriate medications.

Most lumps go away on their own or with appropriate medical treatment. Surgery may be required in some cases. Cancerous lumps may be treated with chemotherapy, radiotherapy, or surgery, or a combination of these.


Rosacea, Acne, Shingles, Covid-19 Rashes: Common Adult Skin Diseases
See Slideshow

Medically Reviewed on 10/20/2021


Kanwar VS. What is axillary lymphadenopathy? Medscape.

National Cancer Institute. Lymph node.

Weerakkody Y. Bilateral axillary lymphadenopathy (differential). Reference article, (accessed on 12 Oct 2021)

Be First to Comment

Leave a Reply

Your email address will not be published.