Causes of Swollen Armpit Lymph Nodes

Lymph nodes of the armpit are known as the axillary lymph nodes. They are usually not palpable (felt by touch) but may sometimes become swollen, hard and/or painful. This can arise from a host of possible causes ranging from minor injuries to infections and even cancer. Apart from the armpit itself, disorders or diseases of surrounding organs may also cause axillary lymph node swelling.

Anatomy of the Axilla (Armpit)

Lymph nodes are small, round or oval glands that are found all over the body and form part of the lymphatic system,. They are an integral part of the immune system. It helps the body to fight against infections while removing interstitial (tissue) fluid and returning it to the blood stream. The lymph nodes act as filters to trap and destroy bacteria, viruses and other harmful substances that enter the body.

Normally the lymph nodes are not palpable but may enlarge as a result of some disorder or disease. The lymph nodes of the axilla (armpit), inguinal region (groin), and neck tend to enlarge more frequently than other areas. Localized lymphadenopathy, where the lymph nodes of a single area are affected, may also be accompanied by lymph node swelling elsewhere. If this occurs, then it is considered as generalized lymphadenopathy and the cause of the swelling may likely be a systemic factor.

The central area of the armpit is surrounded by four walls :

  • an outer (lateral) wall formed by the arm.
  • inner (medial) wall formed by the chest (thorax).
  • front (anterior) wall made up by the pectoralis major muscle.
  • back (posterior) wall made up by the subscapularis, teres major and latissimus dorsi muscle

There are five groups of lymph nodes in the axilla associated with each area – the central, lateral, medial, anterior and posterior groups of lymph nodes.

Hard, Firm or Painful Lymph Nodes

Lymph nodes that are swollen due to infections tend to be firm and painful. Enlarged lymph nodes due to cancer are usually firm or hard in consistency, fixed (not freely mobile), usually not painful, and may be matted (stuck to each other). They may also increase in size over time.

In some cases the lymph nodes may be felt, without the presence of any disease, but are usually small (less than 1 cm in size), soft and painless lumps.

Cysts and abscesses under the skin in the armpit may produce lumps which could be mistaken for enlarged lymph nodes.

Causes of Enlarged Axillary (Armpit) Lymph Nodes

Local Causes

One or more lymph nodes in one or both axilla (armpit) may become swollen commonly due to :

  • Injury to the armpit, arm or hand.
  • Localized infection in the armpit or of the arm, hand or breast, which drains into the axillary lymph nodes.
  • Cat scratch disease is an illness which is caused by the scratch or bite of an infected cat. Cats act as carriers of the bacterium Bartonella henselae which causes cat scratch disease although cats do not suffer from the disease themselves. There may be generalized symptoms of fever, headache, loss of appetite and fatigue along with lymph node swellings, especially of the head, neck and axilla. Cat scratch disease normally resolves on its own without any specific treatment. However the infection may be more debilitating in persons who are immunocompromised like in  HIV/AIDS patients or those on chemotherapy for cancer.
  • Tumor in or near the lymph node.
  • Lymphoma.
  • Breast cancer may cause swollen axillary lymph nodes since the lymph vessels of the breast drain into the lymph nodes of the armpit. These nodes become enlarged when cancer cells spread beyond the breast tissue. The condition of the axillary lymph nodes is very important for staging of breast cancer which can help to determine the prognosis and clinical course of the disease, as well as indicate the best treatment option. Axillary lymph node status may be taken as the single most important factor which helps to determine the prognosis and  survival rate of patients with breast cancer.
  • Melanoma is one of the most dangerous types of skin cancer. It may metastasize (spread) to the nearby lymph nodes.
  • Brucellosis is also known as Undulant fever, Malta fever and Mediterranean fever. This disease is caused by the different strains of the Brucella bacteria which may infect animals such as goats, cows, pigs and dogs. It is spread to humans coming in contact with infected animals, eating or drinking unpasteurized dairy products. Flu-like symptoms may be present such as fever, headache, backache, joint pain, chills, fatigue and poor appetite. Muscle pain and swollen lymph nodes (including axillary lymph nodes) may be associated with this disease. Brucellosis may present as an acute infection or it may become chronic and can persist for years.
  • Perfumes, deodorants and certain cosmetic procedures like hair removal from the armpit may also cause an allergy or inflammation in the area with or without enlargement of the surrounding lymph nodes. Contact dermatitis, folliculitis or an armpit fungus may also develop on the skin of the axilla and cause swollen armpit lymph nodes.

Systemic Causes

Systemic causes of lymph node enlargement may be involved in causing swelling of the axillary lymph nodes before more generalized lymph node involvement becomes apparent.

These causes of axillary lymph node enlargement may include :


  • Infectious mononucleosis (Epstein-Barr virus) which produces symptoms of fever, sore throat and fatigue as well as enlarged lymph nodes.
  • Cytomegalovirus (CMV) – similar symptoms as mononucleosis.
  • Chicken pox (varicella).
  • Herpes zoster (shingles).
  • Measles.
  • Rubella (German measles).
  • Mumps.


  • Cat scratch disease.
  • Lymphadenitis – infection of the lymph nodes, which may be result as a complication of certain bacterial infections.
  • Ascending lymphangitis.
  • Tuberculosis.


  • Sporotrichosis is a chronic skin infection caused by a certain type of fungus found in vegetations such as rose bushes and briars. Small, painless, red lumps appear following an injury, usually on the hands or arms, and may go on to involve the lymph nodes.

Side effects of vaccinations

  • MMR (measles, mumps, rubella) vaccination.
  • Typhoid vaccination.
  • Small pox vaccination.


  • Hodgkin’s lymphoma is cancer of the lymph tissue present in the lymph nodes, spleen, liver, bone marrow and other sites. It initially starts in a single lymph node , spreads to nearby lymph nodes and then to other organs such as the spleen, liver and bone marrow. Painless lymph node swelling of the axilla, neck or groin may be accompanied by fever, chills, night sweats, fatigue, weight loss, itching and various other symptoms.
  • Non-Hodgkin’s lymphoma.
  • Leukemia.
  • Breast cancer.
  • Lung cancer.
  • Melanoma.

Other causes

  • Allergic reaction to sulfur (sulphur) drugs, penicillin or iodine.

Please note that any information or feedback on this website is not intended to replace a consultation with a health care professional and will not constitute a medical diagnosis. By using this website and the comment service you agree to abide by the comment terms and conditions as outlined on this page

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  • Honey Fe

    My axillary lymph nodes in my right armpit is swollen and its really painful, I’ve started feeling it last december but it just goes away after 2 days and it went back again last february, it became bigger and very painful yet after 3 days it was okay and now this is the third time it came back and its really paining me, I’ve experienced the pain for 3 days now, what do you think is the diagnosis? Will this be lead to breast cancer? I just have 6 month old baby and Im still breastfeeding until now during the night. please help.

  • Hi Donna. Yes, the lymph nodes can enlarge with cancer but this is not the only cause. Sometimes a mild inflammation may cause enlargement temporarily and even certain medication, vaccines and autoimmune diseases can have the same effect. Hopefully you have been consulting with a gynecologist regularly due to the concern of breast cancer. Speak to your GP first. It may be nothing major to worry about. Do not interfere with the area as your GP advises as you could causing irritation tissue in the area which you may be mistaking for lymph node enlargement.

  • JussMee

    what??? Have you all gone mad? Why are you writing a web page asking them for a medical diagnosis??? Get some insight, then CALL YOUR FRIGGING DOCTOR LOL!

  • Erin

    Hello, Am a a 30 year old women and currently have swollen lymph nodes in arm pits. I am concerned bc I was originally supposed to have a mammogram but bc I am breastfeeding they told me to do the ultrasound. The radiologist saw the scans from a different location but spoke with the technician and they said it all looks good but my lymph nodes are swollen. I wouldn’t be so worried but my sister was just recently diagnosed with breast cancer and my aunt died last week from breast cancer. They did tell me to follow up with my doc but there was no concern. Should I pursue this further? I am concerned bc of the slight pain in my armpit and the family history.

  • Hi Erin. Yes, it would be advisable that you monitor it closely but swollen armpit lymph nodes can be due to a host of causes. Breast cancer is not the most common cause. However, given your family history it is understandable that you are concerned and you should have regular examinations. It may not be necessary to investigate it further just yet but speak to your gynecologist about your concerns so that you can be monitored in the long term.

  • jemaimah elnar

    I am 28 years old now, I remember my right arm having lymph nodes when I was 15 years old. So I already bringing this more than 10 years now. Is this cancer???

  • Beckie Cann

    I suffer Gulf War Illness (GWI), a subset of Chronic Fatigue Syndrome (CFS). GWI is caused by vaccines, aggravated by battlefield exposures. Second leading cause of CFS is vaccines. Top leading cause of CFS is viral infection of unknown etiology which never improves. Your description is the closest I have ever read as to what happened to me overnight — 26 years. Fibro is almost always a symptom of CFS or the Big Picture. And it’s almost impossible to land disability with a Fibro claim, since many victims can take Lyrica and go on back to work. So I never tried. I also thought it was impossible to acquire disability on claim of chronic Epstein-Barr virus. So I never tried. I DID file my claim for CMV or cytomegalovirus, a green African monkey virus acquired through all vaccines cultured on monkey kidney tissue. Anyone who has ever received childhood vaccines has been exposed to CMV: Lying dormant in their deep tissues until an incurable virus comes along to reactivate live viruses in all vaccines, plus Infectious Mono, which becomes Epstein-Barr virus. None are curable. Most can be pushed into remission with the right treatment. CMV is the lone exception. I’ve suffered through 26 years of chronically active CMV. In me thus far, CFS or GWI have reactivated EBV to become chronic EBV; CMV to become chronic CMV; polio, and mumps. I have been fighting reactivated polio for the past 6 years. I lost one of my major leg muscles and all of my major muscles in both arms. I am otherwise unable to aerobically exercise. So I perform my own fashion of Physical Therapy to build up surviving muscles around those that died: I can’t bear the thought of bedfast and housebound due to reactivating and shedding viruses. CFS is not genetic, does not run in families, does not lead to cancer. Toxic factors of system-wide infection tear down the body’s natural ability to fight cancer. Hard as it might be, I would put cancer on the back burner until you see a CFS physician, who can better answer your very valid questions. A CFS physician, not an Infectious Diseases or any other medical specialty, will be the only type of doc who can write letters of disability to accompany lab test results to SSA for disability. In 2014, Social Security Administration wrote a regulation that really helps you come up with blood tests AND SYMPTOMS that SSA judge will recognize and approve for disability due to CFS. Social
    Security Ruling, SSR 14–1p; Titles II and XVI: Evaluating Claims Involving Chronic Fatigue Syndrome (CFS). More than half of your disability claim for CFS is based on symptoms of 1.) fatigue, your very first, most persistent symptom; 2.) sleep disorders; 3.) co-morbid infections of all kinds, including dental, respiratory, viral, bacterial, fungal, and microbial (parasites); 4.) fevers, chills, and / or subnormal oral temperatures that accompany cold sweats with weakness to the point of collapse; 5.) Sore throat or vocal cords so raw that you cannot speak without coughing; 6.) subnormal body temperature and inability to tolerate cold or heat; etc. The best legal / medical description of CFS – plus signs and symptoms that must persist for 6 months before the diagnosis of “Fatigue” can develop into a diagnosis of “Chronic Fatigue Syndrome” – is on CDC / NIH Office of Women’s Health webpage for Chronic Fatigue Syndrome. Please notice on that webpage that mental illness – such as Somatoform Disorder, depression, anxiety – and Fibro are “separate” medical issues that should be “diagnosed separately”. One reason is because mood-altering drugs will make you much, much sicker; “brain fog” develops into comatose. Another is because once you receive appropriate treatment for CFS, most symptoms that cannot be confirmed by blood test go away or modify to become a symptom of CFS that you can identify. Best example is “depression” and “anxiety”. Auto-immune disease Hashimoto’s thyroiditis causes depression and anxiety. Patients who suffer hypothyroiditis as a major part of CFS should also be screened for Hashimoto’s. Most patients recover from mental symptoms once they receive adequate treatment for all types of hypothyroiditis.

    If you will think back, your very first symptom was “unusual” fatigue, feeling like you were coming down with a viral infection. It might have accompanied dizziness so bad that you developed chronic nausea; disorientation to the point you couldn’t drive or walk down stairs without pitching forward; symptoms of hypotension or changing blood pressure as you rise from seated. Perhaps you even thought you caught something “going around” but recovered only moderately. But your absolute top level of functionality is less than 50% of how you felt at 36 years old. Your disability judge WILL approve you for CFS if you see the right type of doc. I highly recommend that you go outside your health insurance plan to see a CFS doctor – usually listed as Anti-aging medicine, or hormones, or Longevity and Fatigue, or Fibro & Fatigue. Several are listed as thyroid specialists who “balance hormones”. That’s what anti-aging docs do, too. But CFS docs treat EVERYthing simultaneously – multi-faceted treatment for a broad-spectrum “syndrome”: set of diseases, signs, symptoms. I currently suffer 20 different diagnoses, signs and symptoms. Endocrinologists and rheumatologists are useless narcissists. Fibro & Fatigue Centers of America are sprinkled across the nation. F&F accepts insurance or will provide you with itemized statements so that you can file your own insurance claims for reimbursement. F&F Centers also have in-house labs with Quest Diagnostics, who also accepts insurance. Sounds like you suffer hyper-coagulation defect, specifically in Caucasians, as our mutation for survival. English and Welsh fought with narrow, razor-sharp swords, and would have died by them. Except that our immune systems detected “invasion”, and laid down a layer of fibrin protein (not a clot) at the site of sword injury. In CFS, system-wide infection(s) triggered your immune system. And it cannot be turned off. Inside every vessel, fibrin protein continues building up, attempting to protect your immune system from all infections you are fighting. That explains the acne, abscesses, swelling in feet. I fight my own over-active immune system with a daily dose of guaifenisen or generic Mucinex, plus injections into my belly fat with heparin sodium. I also inject with B12 to help with memory and fatigue, bypassing the blood-brain barrier. B12 is a vitamin, which is hard to sufficiently accumulate through diet, and which does not survive gastric acids. With CFS, your digestive tract usually does not absorb as well as it did before you got sick. Hope my research of 26 years helps you and everyone else who is “underdiagnosed” with Fibro.

  • Hi Beckie. Thank you for sharing your experience. It will undoubtedly be helpful to other readers

  • Ariana

    Omgosh! You are so knowledgeable! Thank you! The essence of what you wrote really resonates with me. I’ve had serious issues with fatigue since i was a young teen, but I never knew how to communicate what i was going through, and I certainly didn’t understand why I was so fatigued all the time – to the point of nausea or similar descriptions your wrote. Very familiar to me. It seemed to come and go throughout my life, but I’d say it was there more often than not. I’m sure it was mistaken for laziness, but that really wasn’t true. But you can’t tell other people that. They call it as they see it. No sense in defending myself against something that’s going to count against me anyway. Gotta conserve that energy, Lol. It has always seemed I had digestive issues also. I’ve seen similar things in family members that has had me thinking it has to be relevant in ways that our doctors are not recognizing. There seems to be almost no acknowledgment of how our digestive tracts reflect the status of our health in any way. I think that goes completely against common sense. I appreciate your mention of that. For me, it lends credibility to all you say. Interesting comment, full of information that I will be sure to re-read. Thank you for taking the time to raise my awareness. I’m sorry you’re so ill! I wish you well. You’re a soldier!

  • Jack Leong

    Hi I’m a 15 year old male, i have an underarm lump, just asking is it possible for an underarm lump to spread, if so is that anything bad

  • Hi Jack. It really depends on what the cause of this lump is. Often a lump in the armpit is due to an enlarged lymph node. This is not uncommon when there is an infection. However, another possibility is that a hair follicle in the armpit has become blocked and infected. Whether this will spread or not is difficult to say. You will need a doctor to examine the area and make an exact diagnosis.