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What Should You Do If You Find A Lump In Your Armpit?

An armpit lump is a swelling and painful lump that comes under the arm and can be caused due to various factors. Lumps occurring in armpits are called lymphadenopathy, axillary lymph enlargement, or axillary abscess.

Most armpit lumps eventually disappear without consulting a medical director, but it can take a few weeks. If an armpit lump continues for a few weeks, it may require treatment because if it is a cancerous lump, it may lead to an underlying health issue like cancer.

1. Lymph Nodes

Lymph Nodes: Histology


Lymph nodes are tissues that are present in the body and act on germs and cancerous tumor cells. Their main purpose is to identify external objects entering the body such as bacteria or viruses.

Basically, they play an important role in the immunological action of the body. In terms of size, these tissues can be anywhere up to two centimeters. 

2. Understanding the Causes Of An Armpit Lump

Though lymph nodes may not be visible to the naked eye, those in the neck and armpits tend to be visible more clearly when they bulge. Infections caused by viruses or bacteria can make your lymph nodes bulge out. 

The swollen lymph node is identifiable through touch and is often painless. Other symptoms that indicate the presence of armpit lumps are fever, flu, and irritation.

Most commonly armpit lumps are caused by lipomas, scratch diseases, allergic reactions, or the use of certain vaccinations.

3. How Does A Lump Appear?

A lump or swollen lymph nodes may possess a variety of characteristics:

  • A lump appears as soft and mushy or firm and hard.
  • Lumps may contain pus inside them.
  • There can be both painful and painless lumps.
  • Lumps with irregular contour or reddishness.
  • An armpit lump may be cancerous or non-cancerous.

Diagnosing becomes easier after identifying the type of lump formed in the body.

4. Causes of Armpit Lumps

Armpit Lumps: Causes And Treatment

The most common causes of a lump under the armpit are listed below. For you to know the exact cause of a newly discovered lump, it is necessary to observe the symptoms closely.

4.1. Benign Lump

Benign tumors do not cause cancer. They grow at only one location and do not invade other cells. The lump grows slowly and has a regular shape. As far as treatment is concerned, some lumps can be removed surgically, and for some, they might not need to be removed at all. 

Most tumors do not grow back after surgical removal. Although these tumors are benign, they can cause other health concerns, as they tend to suppress nearby organs or blood vessels. In the worst-case scenario, benign lumps may turn into malignant tumors. 

If an unexplained lump forms and the lump persists for more than a week, it’s better to consult a medical provider. Conditions like Dysplasia (abnormal tissue growth) and Hyperplasia (normal cells grow fast) require deeper analysis. Hence, close observation from your medical provider is necessary before surgically removing them.

4.1.1 Fibroadenoma/ Breast Mouse

Fibroadenoma Definition And Cancer Risk

One of the most common causes of armpit lumps is fibroadenoma. It is a condition of non-cancerous tumor growth in the breast area, which reaches the armpit and makes it identifiable. Breast lumps usually affect females between the ages of 14-40 years. Their lumps are rarely cancerous.

Women with complex fibroadenoma have an increased risk of getting breast cancer. So, it is advisable to consult a medical provider and carry out monthly breast self-exams for any new rubbery lumps.

A lump formed due to fibroadenoma does not require any special treatment. If it is large and grows continuously, then your doctor may advise you to go for further testing. 

4.1.2 Hidradenitis suppurativa/ Acne Inversa

Hidradenitis Suppurativa (HS) | Pathophysiology, Triggers, Signs & Symptoms, Diagnosis, Treatment

Armpit lumps occur due to the formation of lumps at places of skin folding, such as breasts, armpits, and groins. Obesity, leading to skin friction and accumulation of sweat, contributes to its causes. These lumps can be painful and last many years if not treated properly. It can usually occur in the early teens.

Unlike other conditions, this does not require any biopsy test but needs only a few pathological evaluations. Treatment depends on the stage of the disease spread. It begins with giving antibiotics, a few steroidal medications, and ultimately surgery. 

4.1.3 Systemic Lupus Erythematosus

Medical research and reviews from the Dana Farber Cancer Institute prove that an armpit lump also occurs due to autoimmune disorders. Systemic Lupus Erythematosus is one of the autoimmune disorders that leads to the formation of white lumps in various parts of the body, including armpits.

Though inflammation and tissue damage are the primary effects of this disease, it can also cause large masses of lumps, which are painful sometimes. The cure for this disorder is not yet proven.

4.2. Malignant Lump

Benign Tumor Vs Malignant Tumor ( Clear Comparison )

Conversely, malignant tumors are cancerous lumps. Malignant tumors form a mass when cancer cells multiply and attach to the breast tissue. This mass of cells invades the nearby tissues and spreads throughout the body. Thus, it requires immediate treatment. A similar mass formation could be the reason for the breast lump. 

Mass forming due to cancer can also cause a lump in the armpit and requires immediate medical attention. A mammogram is the simplest way of diagnosing breast cancer.

If caught early, chances of successful treatment are high. Once the cancer has spread, the treatment will be more crucial, including treatment options like chemotherapy, radiotherapy, or immunotherapy with surgery.

4.2.1 Breast Cancer

Armpit lumps can be caused by breast cancer too. These lumps are generally hard in touch, and pain-free. People often mistake the sides of the breast to be the armpits, so any lump felt beneath the arm should be checked by a physician first.

Hence, it is good to carry out a physical examination regularly to check for breast cancer, as it can help detect early breast cancer.

4.2.2 Lymphoma

What Is Lymphoma?

Lymphoma is a cancer of the lymphatic system, which is a major part of the body’s immune system to fight against infections.

Typically, most armpit lumps of lymphoma are categorized as Hodgkin lymphoma, which means that it occurs in the upper part of the body.

In this case, lumps in the armpit form due to swelling of lymphocytes, most commonly known as white blood cells. 

4.2.3 Leukemia

It is also a cancer that originates through lymphocytes or white blood cells. But leukemia begins in the bone marrow and grows through the bloodstream, whereas lymphoma forms at the lymph node.

When leukemia spreads to the skin, it can cause a lump in the armpit due to swollen lymph nodes or clusters of rashes from skin irritation. Painful lumps and easy bruising are common symptoms.

 However, it is a rare indication that your lump is leukemic cancer. Most cases of leukemia do not form a solid mass, so they are hard to identify, even in an X-ray.

4.3. Hair Follicle Issues

4.3.1 Skin cysts or abscesses

Cysts or abscesses are fluid-filled sacs that can form anywhere in the body, including the armpit, possibly due to the presence of hair follicles.

They may vary in size and shape. These can be soft to the touch and may stay up to any duration. Cysts can also form due to irritation, sweat, friction, and ingrown hair follicles.

4.3.2 Folliculitis

Folliculitis, Causes, Signs and Symptoms, Diagnosis and Treatment.

The formation of pus-filled bumps in the presence of staphylococci bacteria is called folliculitis. Scarring due to harsh shaving can also lead to folliculitis. Using antibiotics for prolonged periods may also lead to allergic reactions resulting in folliculitis.

Hair growing or curling inwards due to excessive shaving can be a possible cause of a lump in the armpit. Any inflammation of the hair follicles by yeast, insect bites, fungus, or viruses forms carbuncles under the arms.

4.4. Viral Infections

Mononucleosis is a viral infection caused by a herpes virus, that shows the symptoms of swollen lymph nodes and spleen enlargement. It is a contagious condition and transmits from one person to another through blood transfusion, organ transplant, coughing, sexual contact, or sharing food and water. 

Regular exercise suggested by your doctor and the use of antibiotics and nonsteroidal anti-inflammatory can help ease the discomfort and inflammation but does not cure it completely.

Sometimes, bleeding from the ruptured spleen can be life-threatening. There is no clinically approved vaccine as a preventive measure for this condition.

4.5. Fungal Infections

Though fungal infections do not directly cause any armpit lumps, they can indirectly contribute to an armpit lump. Infections like ringworm can affect the skin’s surface, leading to inflammation.

Other symptoms may include swelling and tenderness. The swollen skin may be identified as an unusual lump due to its feel, although it does not seem like a solid mass.

It is also important to understand that an armpit lump can have many causes, including infection, injury, cysts, or underlying health issues like cancer.

It is necessary to seek medical attention before the infection becomes too severe. Healthcare may suggest a few blood tests and antifungal medications if the lump is due to a fungal infection.

4.6. Bacterial Infections

Bacterial infections are the most common cause of an armpit lump. Bacterial infection leads to an armpit lump that forms axillary abscesses. An abscess is a fluid-filled sac and dead tissues. Infection enters the lymphatic system through the skin.

When bacteria travel towards the lymph nodes in the armpit, they activate a signal to the immune system. The immune system response causes a swollen lymph node.

This infection affects the skin’s surface and spreads inside if not treated, as the starting point of entry is the skin. This results in a lump in the armpit.

A newly formed lump in your armpit requires consultation by a healthcare provider. The healthcare provider may suggest you check your complete blood count and prescribe a few antibiotics accordingly.

4.7. Allergic Reactions

Armpit lumps can also be a temporary swelling of the lymph node. Allergic reactions activate our immune system, leading to an increase in cell activity.

This reaction leads to swollen lymph nodes in the armpit as a response to the allergen. The swollen nodes appear to be like a lump. 

4.8. Contact Dermatitis

As the name suggests, this condition happens when the skin comes in contact with certain plants, chemicals, or metals.  

Contact dermatitis causes skin swelling, redness, and the formation of lumps. An insect bite also results in an allergy. If an allergen comes into contact with the skin in the armpit area, it leads to a lump in the armpit.

4.9. Irritant Contact Dermatitis

Irritant contact dermatitis occurs when the skin is exposed to irritant substances, which include harsh chemicals in soaps and detergents. Though ICD does not cause any allergic reaction, it can still cause redness, itching, and lumps.

In case of prolonged irritation, the swelling becomes more, which leads to the formation of lumps on the skin. These lumps may feel soft and painful, accompanied by skin cysts.

4.10. Vaccination

Some people can get an armpit lump after taking a vaccine. The armpit lump often appears in the area where you received the vaccine shot. Some reactions are common when you get a vaccination, which includes redness, swelling of lymph nodes, and sometimes the formation of a small lump.

These reactions are short-term and become normal within a few days. Vaccination also leads to swelling of neighboring lymph nodes, which look like an armpit lump. It is the nature of the immune system to react to the vaccine.

5. Conclusion

Finally, most lumps with swollen glands result from numerous factors, including infections from bacteria and viruses, allergies, skin conditions, cysts, and, in rare cases, various types of cancer. In any case, early detection of these armpit lumps and subsequent treatment is better to maintain health.

Regular self-exams and clinical examinations by healthcare providers are essential for monitoring changes in your armpit and breast health. Understanding your risk factors, including medical history, can help guide your approach to breast health and screening.

Discuss your risk profile with your medical provider, especially an internal medicine practitioner, for better diagnosis and to stop a new lump in your armpit or anywhere in your body.

Last Updated on December 20, 2023 by