Armpit Lumps Symptoms, Causes & Common Questions

Understand your armpit lumps symptoms, including 10 causes & common questions.

Coronavirus: Check your symptoms

Use Buoy Assistant to figure out if you should seek care for COVID-19.


  1. Symptoms
  2. Causes
  3. 10 Possible Armpit Lumps Conditions
  4. Treatments and Relief
  5. Real-Life Stories
  6. FAQs
  7. Questions Your Doctor May Ask
  8. Statistics
  9. Related Articles
  10. References

Armpit Lumps Symptoms

It's not uncommon to discover a lump under your arm. Women are especially likely to discover them while shaving or during other self-care routines. These unexplained armpit lumps shouldn't be ignored; however, there is often a normal and treatable cause behind them.

Lymph nodes are responsible for retaining and destroying any invading bacteria or other organisms. These nodes can sometimes become swollen from filtering harmful cells, commonly in the groin, neck, and armpits.

An armpit lump may also be called axillary lymphadenopathy or axillary lymphadenitis, which are related to inflammation or infection of the lymph nodes in the armpit. Axillary lymphangitis is related to inflammation or infection of the lymphatic vessels in the armpit.

Common characteristics of armpit lumps

A lump or swelling in or near the armpit may be described as:

  • Almost any size
  • Sore or painless
  • Reddened or of normal skin color
  • Soft or firm
  • Mobile: This means the lump can be moved around, which is less concerning.
  • Fixed: If the lump seems to be in stuck one spot and seems different from surrounding tissue, you should consult your physician.

Common accompanying symptoms of armpit lumps

In addition to the lump itself, you may also experience the following associated with an infection:

Duration of symptoms

The lump may resolve on its own after a few days, but most lumps will only grow larger or more infected if ignored.

Who is most often affected?

People who are most likely to experience armpit lumps include the following.

  • Women: Lumps may be caused by underarm shaving, breastfeeding, or breast cancer.
  • Anyone with an infection: Such as a systemic illness or a localized infection in the arm or breast
  • Anyone with the Epstein-Barr virus (EBV): This may contribute to some forms of lymphatic cancer [1].

Is an armpit lump serious?

The causes of armpit lumps vary in severity.

  • Not serious: A lump caused by a minor event, such as an insect bite or ingrown hair, is rarely serious as long as it is properly treated.
  • Moderately serious: Signs of infection or abscesses, such as painful, reddened lumps, may require antibiotics or even surgery to cure.
  • Serious: An isolated lump can be a sign of breast or lymphatic cancer and should be seen by a medical provider as soon as possible.

Armpit Lumps Causes

Many conditions can cause the symptom of armpit lumps [2]. The following details may help you better understand your symptoms; however, if your condition persists, you should see a physician for a proper diagnosis.

Inflammatory causes

Inflammatory causes of armpit lumps are likely due to an infection. If the lump itself is not infected, the infection — likely a systemic or body-wide infection — can cause lymph node swelling as the body attempts to fight the invading germs.

  • Bacterial infections: These can cause painful, reddened swellings called abscesses or boils. Bacteria that commonly affect the lungs and other areas include staphylococcus or streptococcus, as well as Mycobacterium and Bartonella.
  • Viral infections: These can also cause upper respiratory and ear infections, as well as many other illnesses.
  • Fungal infections: Candida, commonly called "yeast," can cause clusters of small swellings under the arm.
  • Single-celled parasitic organisms: Toxoplasma gondii can cause flu-like symptoms and lymph node swelling.
  • Autoimmune illnesses: These cause inflammation throughout the body that provokes swelling in the lymph nodes.
  • Inflammation of sweat glands under the arm: This can cause painful, reddened clusters of large and small bumps in and under the skin, and may also be related to infected hair follicles, infected ingrown hairs, or infected insect bites.

Contact allergies

Contact allergies can cause armpit swelling as one or more lumps.

  • Antiperspirants and deodorants
  • Soaps
  • Perfumes
  • Laundry soaps and fabric softeners

Medication-related causes

Certain medications can cause a kind of allergic reaction that includes swollen lymph nodes under the arm. Vaccines work by actually giving you a very mild form of the disease they are protecting against. This mild disease can be enough to cause temporary swelling of the lymph nodes under your arm.

Rare and unusual causes

Rare and unusual causes of armpit lumps include [3]:

  • Normal breast tissue: Occasionally, normal breast tissue can extend into the armpit and cause a lump or bulge.
  • Lipoma: This is a benign fatty tumor often found under the arm.
  • Lymphoma: This is cancer of the lymph nodes.
  • Breast cancer: An armpit lump can be a sign of breast cancer in anyone, not just women.

10 Possible Armpit Lumps Conditions

The list below shows results from the use of our quiz by Buoy users who experienced armpit lumps. This list does not constitute medical advice and may not accurately represent what you have.

Skin cyst

A cyst is a small sac or lump, filled with fluid, air, fat, or other material, that begins to grow somewhere in the body for no apparent reason. A skin cyst is one that forms just beneath the skin.

It's believed that skin cysts form around trapped keratin cells – the cells that form the relatively tough outer layer of the skin.

These cysts are not contagious.

Anyone can get a skin cyst, but they are most common in those who are over age 18, have acne, or have injured the skin.

Symptoms include the appearance of a small, rounded lump under the skin. Cysts are normally painless unless infected, when they will be reddened and sore and contain pus.

Diagnosis is made through physical examination. A small cyst can be left alone, though if it is unsightly or large enough to interfere with movement it can be removed in a simple procedure done in a doctor's office. An infected cyst must be treated so that the infection does not spread.

Rarity: Common

Top Symptoms: skin-colored armpit bump, marble sized armpit lump, small armpit lump

Symptoms that always occur with skin cyst: skin-colored armpit bump

Urgency: Wait and watch

Enlarged lymph nodes in the armpit

Enlarged lymph nodes occur when the node becomes larger as it fills with inflammatory cells. This often is a result of an infection but can occur without a known cause.

Rarity: Common

Top Symptoms: armpit lump, movable armpit lump

Symptoms that always occur with enlarged lymph nodes in the armpit: armpit lump

Symptoms that never occur with enlarged lymph nodes in the armpit: fever, unintentional weight loss, hard lump in the armpit

Urgency: Phone call or in-person visit


Lipoma is a word that translates as "fatty tumor," but a lipoma is not cancer. It is simply a growth of fat between the muscle layer and the skin above it.

The exact cause is not known. The condition does run in families and is associated with other unusual syndromes such as adiposis dolorosa, which is similar. Lipomas most often appear after age 40.

Symptoms include a soft, easily moveable lump beneath the skin, about two inches across. A lipoma is painless unless its growth is irritating the nerves around it. They are most often found on the back, neck, and abdomen, and sometimes the arms and upper legs.

It is a good idea to have any new or unusual growth checked by a medical provider, just to make certain it is benign.

Diagnosis is made through physical examination, biopsy, and imaging such as ultrasound or CT scan.

Most of the time, treatment is not necessary unless the lipoma is unsightly or is interfering with other structures. It can be removed through surgery or liposuction.

Rarity: Uncommon

Top Symptoms: skin-colored groin bump, marble sized groin lump, small groin lump

Symptoms that always occur with lipoma: skin-colored groin bump

Urgency: Wait and watch

Skin abscess

A skin abscess is a large pocket of pus that has formed just beneath the skin. It is caused by bacteria getting under the skin, usually through a small cut or scratch, and beginning to multiply. The body fights the invasion with white blood cells, which kill some of the infected tissue but form pus within the cavity that remains.

Symptoms include a large, red, swollen, painful lump of pus anywhere on the body beneath the skin. There may be fever, chills, and body aches from the infection.

If not treated, there is the risk of an abscess enlarging, spreading, and causing serious illness.

Diagnosis is made through physical examination.

A small abscess may heal on its own, through the body's immune system. But some will need to be drained or lanced in a medical provider's office so that the pus can be cleaned out. Antibiotics are usually prescribed.

Keeping the skin clean, and using only clean clothes and towels, will help to make sure that the abscess does not recur.

Rarity: Common

Top Symptoms: rash with bumps or blisters, red rash, red skin bump larger than 1/2 cm in diameter, pus-filled rash, rash

Symptoms that always occur with skin abscess: rash with bumps or blisters

Urgency: Primary care doctor

Boil (furuncle)

A furuncle, also called a boil, is infection of a hair follicle. The infection forms under the skin at the root of the hair and may occur anywhere on the body.

The infection is caused by bacteria, most often Staphylococcus aureus or "staph." Irritation caused by clothes or anything else rubbing the skin can cause the skin to break down and allow bacteria to enter.

Staph bacteria are found everywhere. Frequent and thorough handwashing, and otherwise maintaining cleanliness, will help to prevent its spread.

Most susceptible are those with a weakened immune system; diabetes; and other skin infections.

Symptoms include a single bump under the skin that is swollen, painful, and red, and contains pus.

It is important to treat the boil, since infection can spread into the bloodstream and travel throughout the body.

Diagnosis is made through physical examination and sometimes fluid sample from the boil.

Treatment may involve incision and drainage of the infection, followed by creams to apply to the site of the boil and/or a course of antibiotic medicine.

Rarity: Uncommon

Top Symptoms: pink or red facial bump, small facial lump, painful facial bump, marble sized facial lump, constant skin changes

Symptoms that always occur with boil (furuncle): pink or red facial bump

Symptoms that never occur with boil (furuncle): fever

Urgency: Self-treatment

Armpit Lumps Symptom Checker

Take a quiz to find out what might be causing your armpit lumps


Pimples are also called comedones, spots, blemishes, or "zits." Medically, they are small skin eruptions filled with oil, dead skin cells, and bacteria.

Pimples often first start appearing at puberty, when hormones increase the production of oil in the skin and sometimes clog the pores.

Most susceptible are teenagers from about ages 13 to 17.

Symptoms include blocked pores that may appear flat and black on the surface, because the oil darkens when exposed to the air; blocked pores that appear white on the surface because they have closed over with dead skin cells; or swollen, yellow-white, pus-filled blisters surrounded by reddened skin.

Outbreaks of pimples on the skin can interfere with quality of life, making the person self-conscious about their appearance and causing pain and discomfort in the skin. A medical provider can help to manage the condition, sometimes through referral to a dermatologist.

Diagnosis is made through physical examination.

Treatment involves improving diet; keeping the skin, hair, washcloths, and towels very clean; and using over-the-counter acne remedies.

Rarity: Common

Top Symptoms: pink or red facial bump, small facial lump, painful facial bump, marble sized facial lump

Symptoms that always occur with pimple: pink or red facial bump

Urgency: Self-treatment

Severe skin abscess in the armpit

A skin abscess is an infection of the deeper skin that's typically due to bacteria seen on the skin. Recently, infections are more frequently caused by Staph. Aureus (puts the "staph" in "staph infections"). If the infection begins to spread, urgent treatment is required.

Rarity: Rare

Top Symptoms: fatigue, fever, painful armpit lump, pink or red armpit bump, marble sized armpit lump

Symptoms that always occur with severe skin abscess in the armpit: pink or red armpit bump, red bump

Urgency: Hospital emergency room


Warts, also called common warts or verrucae, are small, rough, rounded growths on the top layer of the skin. They may appear alone or in clusters. Common warts are caused by the human papillomavirus (HPV) and are contagious through direct contact. They may spread from one place on the body to another simply through touch.


Read more

Hodgkin's lymphoma

Hodgkin lymphoma, formerly known as Hodgkin's lymphoma or Hodgkin's disease, is cancer of the lymphatic system. It is believed to be caused by a mutation in one of the body's immune system cells, called a B cell.

Most susceptible are those under age 30 or over age 55, with a family history of the disease, as well as anyone with a history of any illness caused by the Epstein-Barr virus.

Symptoms include swelling of lymph nodes in groin, armpits, and neck; lowered tolerance to drinking alcohol, including pain in lymph nodes afterwards; unintended weight loss; fever; chills; night sweats; and itching.

There are good treatments available for Hodgkin lymphoma, so it is important to see a medical provider about these symptoms as soon as possible.

Diagnosis is made through physical examination; blood tests; imaging such as x-ray, CT scan, or PET scan; and sometimes lymph node biopsy and/or bone marrow sample.

Treatment involves a combination of chemotherapy and radiation therapy. Bone marrow transplant, also called stem cell transplant, can be done in some cases.

Rarity: Rare

Top Symptoms: fatigue, loss of appetite, abdominal pain (stomach ache), shortness of breath, fever

Symptoms that never occur with hodgkin's lymphoma: pulsing armpit mass, armpit lump that comes and goes, shrinking armpit lump, pink or red armpit bump, black or brown armpit bump, yellow or white armpit bump, bleeding armpit bump

Urgency: Primary care doctor

Breast cancer

There are several types of breast cancer, depending on the part of the breast where it starts. The most common types are ductal carcinoma in situ (DCIS), invasive ductal carcinoma and invasive lobular carcinoma.

Women over age 50 with a family history of the disease, and/or certain genetic factors, are most at risk, but anyone can get breast cancer at any age. It is rare in men but does occur.

Symptoms include a lump, thickening, or pain anywhere in the breast or armpit; red, flaky, or irritated breast or nipple skin; nipple discharge; and any area of irregular skin or misshapenness.

Many harmless conditions can cause similar signs, so it is important to see a medical provider about any of these symptoms.

Diagnosis is made through physical examination; imaging such as ultrasound, mammogram, or MRI; and sometimes biopsy.

Treatment involves a combination of surgery, radiation therapy, and chemotherapy.

The best prevention is a combination of screening mammograms as recommended by the medical provider, and monthly self-examination.

Rarity: Uncommon

Top Symptoms: breast pain, armpit lump, breast mass or retraction, breast lump, nipple discharge

Urgency: Primary care doctor

Armpit Lumps Treatments and Relief

Treatments for armpit lumps can begin at home if your symptoms are not severe. You may need to consult your physician if symptoms persist, however.

At-home treatments

Treatments for armpit lumps can begin at home, including the following.

  • Pain medication: For a sore, reddened lump that you suspect is a localized infection, use hot compresses and over-the-counter, non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin).
  • Hygiene: Keep the underarm area very clean and dry and be gentle while shaving. This will help to avoid infections and ingrown hairs.

When to see a doctor

You should consult your physician to discuss the following.

  • Examinations: You should point out any unexplained armpit lumps, especially ones that have persisted for more than a week or so.
  • Treatments: These should be given for any lumps that appear to be infected or for any systemic illness that appeared around the same time as the lump.

When it is an emergency

The presence of the following symptoms in addition to an armpit lump constitutes an emergency.

  • You have started a new medication: Seek care if a widespread skin rash, fever, and swollen lymph nodes occur.
  • You have an abscess and additional symptoms: Such as high fever, chills, shaking, sweating, and rapid breathing and heart rate

Real-life Stories

Once your story is reviewed and approved by our editors, it will live on Buoy as a helpful resource for anyone who may be dealing with something similar. If you want to learn more, try Buoy Assistant.

FAQs About Armpit Lumps

Are cancerous armpit lumps painful?

A lump that is caused by cancer may or may not be painful [4]. Pain is not an indication of whether or not any particular lump is concerning. Most often, a cancerous lump will be hard and painless; but again, this is not always the case. Any suspicious lumps should be examined by your physician.

Are cancerous armpit lumps hard and immovable?

In most cases, yes, and in most cases, it will be painless. A benign lump is most often soft and moveable since it only contains fluid and fat, but harmless scar tissue can form lumps, too, and those will seem hard. The only way to know for certain is to have your physician examine any suspicious lumps.

What causes a soft armpit lump?

A lipoma is a small lump or bulge that is primarily made up of fat. This makes it soft, rubbery, and easily moveable. These are rarely cancerous and usually not painful. Another common soft lump is a cyst, a small sac filled with fluid, pus, or even gas. These are also soft and moveable, rarely painful, and almost never cancerous [5].

What causes a sore or painful armpit lump?

A hair follicle, sweat gland, or small cut in the armpit can become infected and form an abscess, which is a reddened, painful lump. Some women have breast tissue that extends up into the armpit and, as with the rest of the breast, this tissue can also become somewhat tender and lumpy just before menstruation.

Does breastfeeding cause lumps to form in the armpit?

Some women have breast tissue that reaches into the armpit, and this tissue will also become engorged and somewhat lumpy during breastfeeding. Mastitis, which is an infection of breast tissue in a nursing mother, can cause the lymph nodes in the armpit to swell in the same way any other illness does [6,7].

Questions Your Doctor May Ask About Armpit Lumps

To diagnose this condition, your doctor would likely ask the following questions:

  • What color is the bump?
  • Any fever today or during the last week?
  • Do you have a rash?
  • Do you feel pain when you touch the bump?

If you've answered yes to one or more of these questions

Armpit Lumps Symptom Checker

Take a quiz to find out what might be causing your armpit lumps

Armpit Lumps Symptom Checker Statistics

People who have experienced armpit lumps have also experienced:

  • 10% Painful Armpit Lump
  • 6% Armpit Pain
  • 4% Armpit Lump

People who have experienced armpit lumps were most often matched with:

  • 100% Enlarged Lymph Nodes In The Armpit

People who have experienced armpit lumps had symptoms persist for:

  • 43% Less than a week
  • 21% Over a month
  • 13% Less than a day

Source: Aggregated and anonymized results from Buoy Assistant (a.k.a. the quiz).

Armpit Lumps Symptom Checker

Take a quiz to find out what might be causing your armpit lumps


  1. Epstein-barr virus and infectious mononucleosis. Centers for Disease Control and Prevention. Updated May 8, 2018. CDC Link
  2. Vorvick LJ. Armpit lump. U.S. National Library of Medicine: MedlinePlus. Updated August 26, 2017. MedlinePlus Link
  3. Vorvick LJ. Armpit lump. Penn State Hershey. Updated August 26, 2017. Penn State Hershey Link
  4. Breast cancer symptoms: What you need to know. American Cancer Society. Published September 27, 2018. American Cancer Society Link
  5. Miller JM, Morrell N, Quinn RH. Lipoma. American Academy of Orthopaedic Surgeons: OrthoInfo. Updated August 2018. OrthoInfo Link
  6. Mastitis. American Cancer Society. Updated September 20, 2017. American Cancer Society Link
  7. Marshall SA, Husney A, Romito K, eds. Mastitis while breastfeeding. University of Michigan: Michigan Medicine. Updated November 21, 2017. U of M Health Link

No ads, doctor reviewed. Let's crack your symptom code together - like us on Facebook to follow along.