About The Medical Reviewer
Dr. Waks received her undergraduate degree from Princeton University in 2006 and her MD degree from Harvard Medical School in 2011. She completed residency training in internal medicine at Brigham and Women’s Hospital, where she subsequently served an additional year as a Chief Resident in Internal Medicine. She completed fellowship training in medical oncology at Dana-Farber/Partners CancerCare, then joined the staff of the Breast Oncology Center at Dana-Farber Cancer Institute.
Why Is The Lump On My Armpit Painful
Lumps in the armpit, even painful lumps, are common. The majority of armpit lumps are not life- or limb-threatening. Usually, a painful lump in the armpit is due to a clogged pore, a swollen lymph node, or a cyst. These bumps may be pea-sized, inflamed, tender to the touch, and can cause pain when lifting the arm as well.
When To See Your Gp
You should see your GP if you develop any growth or swelling on your body. They can examine it and confirm what it is and what’s causing it.
If your GP is uncertain, they may recommend that you have an ultrasound scan or a biopsy. Surgery may be needed to remove certain types of lump.
You should also see your GP urgently if you have a lump that:
- is getting bigger
- grows back after it’s been removed
This is usually the type of lump that needs treatment or investigation due to infection or to rule out cancer.
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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 : This may contribute to some forms of lymphatic cancer.
Infectious Causes Of An Underarm Lump

An underarm lump caused by a bacterial infection can be associated with serious and potentially life-threatening complications if the infection is not treated promptly with antibiotics. Potential infectious causes of an underarm lump include:
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Bacterial infection, such as a streptococcal or staphylococcal infection
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Cat scratch fever
- Vaccination for various viral diseases, including measles, mumps and rubella
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What Is An Underarm Lump
An underarm lump generally refers to swelling or enlargement of one of the axillary lymph nodes located under the arm . Lymph nodes are very small clusters of immune cells that are an important part of the bodys lymphatic system, which is a part of the immune system. Your body relies on the lymphatic system to fight off germs, infections, and abnormal substances, such as cancer cells.
There are more than 600 lymph nodes throughout the body, but the ones most frequently enlarged or swollen are found in the neck, under the chin, under the arms, and in the groin. An enlarged lymph node under your arm can result from infection, malignancy, and autoimmune disorders.
Swollen lymph nodes are also known as lymphadenitis, lymphadenopathy, swollen nodes, or swollen glands. They can occur in any age group or population, but generally occur most often in children.
An underarm lump due to a viral infection often gets better on its own. However, some infections that are caused by bacteria or other pathogens need medical attention. An underarm lump can also be a sign of breast cancer. Seek prompt medical care if an underarm lump has been present for more than two weeks, is growing, or is red, tender, hard, or irregular in shape.
Questions For Diagnosing The Cause Of An Underarm Lump
To diagnose the underlying cause of a lump under your arm, your doctor or licensed health care practitioner will most likely ask you several questions related to your symptoms. Questions for diagnosing the cause of an underarm lump include:
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Are you breast-feeding?
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Are you experiencing any other symptoms, such as a sore throat or fever?
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Have you noticed any changes in your breast, such as a lump?
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How long have you had the lump?
- Is the lump red or painful?
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Lump On The Shoulder Back Chest Or Arm
A lump on the shoulder, back, chest or arm is most likely to be a lipoma or a cyst.
A lipoma is a soft, fatty lump that grows under the skin. It’s fairly common, harmless and can usually be left alone. When you press a lipoma, it should feel soft and doughy to touch. It can range from the size of a pea to a few centimetres across.
A cyst is a sac under the skin that contains fluid, usually pus. It can look a bit like a lipoma but is close to the surface of the skin .
Cysts can be soft or firm to the touch. Pressing on it you may get a sense of being able to squash it, and it then returning to its original shape once you remove your finger. A cyst may disappear without treatment or you may need to have it drained.
See your GP for advice if you have a lump on the shoulder, back, chest or arm.
Will My Armpit Lump Go Away On Its Own
Yes, most armpit lumps will dissipate with time, depending on the cause. Lumps from infection or blocked pores will disappear as the infection or bodily illness resolves. In the case of a skin infection, this may take a week or so. In the case of a swollen lymph node from a viral infection, it may take up to 10 days. If the lump is from using a deodorant or lotion that blocks pores , resolution may require switching products. Persistent armpit lumps, especially if they are hard and fixed in place, deserve medical attention.
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Can Shaving Cause Armpit Lumps
Yes, shaving can cause armpit lumps. This is most commonly caused by ingrown hairs or small cuts and abrasions in the skin of the armpit. As they heal and skin regrows, the hair may grow into the skin instead of outward. Hair follicles are often colonized by bacteria. If the hair grows into the skin, the bacteria will have no means of drainage from the skin and a bacterial infection may form, causing inflammation and pain.
Armpit Lumps In Women
Armpit lumps can occur in men and women of all ages. However, a lump under the arm could indicate breast cancer. Women should perform monthly breast self-exams and report any breast lumps to a doctor right away.
Note that breasts undergo hormonal changes during the menstrual cycle and may tend to feel more tender or lumpy during this time. This is considered to be completely normal. For the most accurate results, perform breast self-exams about one to three days after your period ends.
Another potential cause of armpit lumps in women, which tend to also occur near the breast and groin regions, is hidradenitis suppurativa. This chronic condition involves clogging and inflammation near apocrine glands of hair follicles in the skin, commonly causing painful boil-like lumps that fill with pus, leak, and possibly even become infected.
Risks for having this condition include tobacco smoking, family history, and obesity. Although the exact cause is not known, it is thought that possibly hormonal changes of puberty and/or the immune system responding too strongly to the hair follicles becoming clogged and irritated. Men can also have hidradenitis suppurativa, but it is much more common in women.
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If You Should See A Doctor Right Away
When the lump under your armpit is red, sore or has suddenly come up generally overnight that is likely a swollen lymph node. Its okay to go ahead and wait some time to check if the swelling and pain self-correct. Although it could remain swelled for several weeks, a swollen lymph node typically grows less and less painful in as much as several days.
Another difference between lymph nodes and lumps is that when the feeling of the lump is not sore or somewhat sore and it stays for numerous weeks, it would be smart to give us a call. This is the best way to prevent breast cancer from arising.
Its Cat Scratch Disease

Weirdly, cat scratch fever is a real thing. This funny-sounding condition is one of the possible culprits behind an armpit lump, according to MedlinePlus. About half of cats carry a bacterium called Bartonella henselae, which they can spread via a scratch. Once the bacteria enters your skin, you can develop an infection that causes the lymph nodes in your underarm to swell. The treatment? Wait it out, or if it persists, antibiotics.
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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.
Its An Inflamed Sweat Gland
Everyone knows about sweaty pits. When sweat-producing glands or hair follicles get clogged, bacteria can sweep in and produce a cyst that later bursts, infecting even more follicles. If the cycle repeats, it can develop into a chronic skin condition called hidradenitisthis hits up to three percent of people in the United States, explains Hopkins Medicine. This network of cysts may be itchy, painful, and even impact your quality of life. Although theres no cure for hidradenitis, your doctor can prescribe medication or other therapies like laser hair removal to improve your comfort.
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Does The Lump Resemble A Pimple
Cancer doesn’t grow nearly as quickly as an infection, nor does it typically cause skin redness. If the lump you have feels and acts like or a pimplethen thats probably what it is. If its a pimple, keep the area clean and dry and apply warm compresses if it doesnt start to abate in a couple of days, see your doctor for treatment. Your doctor will want to rule out a skin condition, such as .
Are Armpit Lumps Serious
The severity of your armpit lump is ultimately determined by the cause.
- Not serious: A small lump or swelling that clears up on its own is probably not serious.
- Moderately serious: A lump that is reddened, painful, and/or persistent should be examined by a medical provider.
- Serious: A lump that is large, reddened, painful, and continues to grow, especially if you also have a fever, should be examined by a medical provider.
What is causing your armpit lump?
- Laundry soaps and fabric softeners
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What Causes Armpit Lumps
As pointed above, most armpit lumps are harmless and should not stress you at all. They are, indeed, the result of an abnormally large tissue growth, usually hard to touch, but are in no way dangerous to your health. Actually, studies have shown that most of the times, people donât even notice these lumps in the armpits. Also, if they do notice them, the bumps go away by themselves, without any medical intervention at all. Here are the most common causes when it comes to armpit lumps.
- Infections that have an either bacterial or viral root
- Lipomas, which are completely harmless tissue growths, usually fat
- Allergic reactions to almost anything, ranging from food to hygiene products
- An adverse response to a particular vaccine
- Infections caused by fungi
- Fibrous tissue growth but that is non-cancerous and which is called fibroadenoma
- Response to breast cancer, seeing as, sometimes, carcinogenic cells, which are movable, can climb from the chest area to the armpits.
- Lymphoma, which is a form of cancer that attacks the lymphatic system
- Leukemia or a kind of cancer concentrating on blood and bone marrow
- Lupus or SLE, a disease that is auto-immune in nature and that affects your joints and internal organs.
Women, in particular, are always advised to get their armpit lumps checked out, as they might, indeed, be a sign of breast cancer. Prevention is always better than cure, so, ladies, going to the doctor or taking the test once a month may save you from the worst!
Serious Symptoms That Might Indicate A Life
An underarm lump that occurs with breast pain, a breast lump, or other changes in the breast may be a symptom of breast cancer or a breast infection. Seek prompt medical care if you think you have symptoms of breast cancer.
In some cases, an underarm lump may occur with symptoms that might indicate a serious or life-threatening condition that should be immediately evaluated in an emergency setting. Seek immediate medical care if you, or someone you are with, have these serious symptoms:
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Change in level of consciousness, confusion or alertness
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Hardened lymph node that may be growing
- Tender, warm and red lymph nodes
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When To See A Doctor
You should see a doctor for the following.
- Any unexplained lump in your armpit: Especially if you are a woman and have no other symptoms of illness
- Swelling that persists or worsens over several days: Especially if you also develop a fever or other symptoms of illness.
- 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 You Should Call Your Doctor

Theres no reason why you should suffer with a lump in your armpit, especially if youre feeling pain. And although your armpit lump is most likely a treatable skin issue like a cyst, occasionally it can be an indication of cancersuch as breast cancer, which can spread to lymph nodes in the armpit. A lump in the armpit is also one of the most common signs of Hodgkin lymphoma, a type of cancer that originates in white blood cells, according to the American Cancer Society the other lymph nodes that may swell include the ones in the neck or groin. If youre concerned for any reason or symptoms are getting worse or not going away, make an appointment with your doctorespecially if you notice any of these strange symptoms that can signal serious disease.
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Hard Lump In My Upper Arm
I’ve got a hard 1-4 inch lump in my upper arm about 3 inches below the armpit. It’s moveable and seems to be attached to something. My doctor said it could be scar tissue but I’m still worried. I’m a 38 year old male.
1 March 2021
Most lumps are harmless and can be a variety of things, from a simple cyst to, rarely, something more serious. They can be caused by infections, inflammation, disease or trauma. Its important to have all the information to make a diagnosis. So, for example, if there has been no injury near the area where your lump has developed, its unlikely to be scar tissue.
A lump like the one you describe could be:
Lymph gland
The location of your lump near the lymph glands in your armpit suggests that this could be a raised lymph gland, caused by an infection.
Epidermal cyst
These affect the epidermis layer of the skin and are made up of keratin and fat. They are generally found on the face, neck, shoulders, chest and upper body and can be triggered by acne or mild injuries to the skin. Look for a slowly developing cyst with a rounded appearance, often no larger than 5cms in size. Key characteristics of epidermal cysts:
- Usually not painful unless they’re burst or become infected
- Usually non-cancerous
- These cysts tend to disappear without treatment but if need be, can be treated with antibiotics, steroid injections or excision .
Pilar cyst
- They run in families
What Does A Cancer Lump In The Armpit Feel Like
A normal lymph node should have the shape of a lima bean. It should also be somewhat firm, but still have some give to it. A cancerous lymph node will often become rock hard. It will also lose the lima bean shape and become more rounded like a marble.
If a swollen lymph node is overly firm and is not shaped like a lima bean, it could potentially be cancerous. Likewise, if the lump is obviously not in the skin, and if it persists, gets larger, and is not accompanied by signs of an infection, it may be time to seek medical attention.
Remember: It is impossible to diagnose cancer by touch so if you are concerned or notice these symptoms, you should contact your doctor. While a lump in the armpit is usually not something to worry about, and the explanation for it is usually something mild and relatively harmless, it is better to be safe and have it checked out.
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Differences In Men And Women
Women should be extra aware of armpit lumps, as they may be an indicator of breast cancer.
While breast cancer can affect males as well , it is far more common in women.
Women should do monthly breast self-exams.
They should also see medical providers regularly for routine screenings and care.
Any new lumps, in the armpit or elsewhere, should be reported to a healthcare provider right away.
People who were born male should still report lumps to their doctor or healthcare provider, but the likelihood of those lumps being related to breast cancer are significantly lower.
Regular breast exams are important for women for the following reasons:
- Breasts can change throughout the menstrual cycle in response to hormones. At certain times of the cycle, especially before and during a period, breasts may feel tender, sensitive, or even feel more lumpy from water retention.
- The best practice is to perform self-exams at the same time every month, usually 1-3 days after a period has ended. This is the time in a cycle where there is the least amount of hormonal changes to the breasts.
- Routine breast cancer screenings are important for everyone, but even more so if there is any family history of breast cancer, or if your doctor has indicated that there are other risk factors. Screening guidelines can vary, but generally women should start getting regular mammogram screenings at age 40.