Common Causes of Lumps Under the Armpit
Some individuals may notice the presence of lumps or bumps under their armpits, which can arise for a variety of reasons. Below, we outline the most significant causes in detail:
Lymph Node Enlargement
Lymph node enlargement, or lymphadenopathy, typically occurs as a response to viral or bacterial infections. This bodily reaction often manifests as lumps under the armpit due to the body’s efforts to combat the infection. We will discuss the infections responsible for lymph node enlargement in more detail:
Bacterial Infections
Certain bacterial infections can affect the lymph nodes located in the armpit region. The following table provides an overview of some of these infections:
| Type of Bacterial Infection | Description | Key Symptoms |
| Cellulitis | A skin infection that arises when bacteria penetrate the skin layers, typically affecting the middle layer. Bacteria may enter deeper layers following injuries or cuts. | Enlargement of nearby lymph nodes, for example, an arm infection might cause swelling of the lymph nodes in the armpit. |
| Lyme Disease | This condition is transmitted through the saliva of certain types of ticks, which can bite humans. | Lymph node swelling is often an early symptom, typically appearing 3 to 30 days post tick bite. |
Other bacterial infections, such as Chlamydia, Syphilis, and Tuberculosis, may also result in lymph node swelling.
Viral Infections
Viral infections can lead to conditions like upper respiratory tract infections, ear infections, and various other illnesses. Some of these include:
- Chickenpox
- Human Immunodeficiency Virus (HIV)
- Mumps
- Measles
- Rubella
Fungal Infections
Candidiasis, commonly referred to as a yeast infection, can cause small lumps to form under the armpit.
Single-Celled Parasites
Some parasites, particularly Toxoplasma gondii, can result in swollen lymph nodes and provoke flu-like symptoms.
Fibroadenomas
A fibroadenoma is a benign tumor that appears as a firm, rubbery lump, which can be mobile beneath the skin but does not shift significantly from the breast area. These tumors vary in size, although most remain constant, while some may shrink or grow. Hormones often influence these tumors, causing size changes during the menstrual cycle and pregnancy. Women may find that fibroadenomas feel softer prior to their menstrual periods; while typically painless, they can occasionally cause discomfort.
Autoimmune Disorders
Certain autoimmune conditions, where the immune system attacks healthy body tissues, may also cause lumps to appear under the armpit. Some notable disorders include:
- Rheumatoid Arthritis
- Juvenile Rheumatoid Arthritis
- Systemic Lupus Erythematosus
Sweat Gland Inflammation
Hidradenitis occurs due to infection and inflammation of hair follicles and sweat glands in the armpit. Symptoms commonly associated with hidradenitis include:
- Severe itching
- Recurring infections
- Formation of small tunnels under the skin
- Scarring
- Feeling of pain
Contact Dermatitis
Contact dermatitis may result in the emergence of one or more lumps under the armpit. Some common causes include:
- Soaps and fragrances
- Clothing detergents and fabric softeners
- Use of antiperspirants and deodorants
Medication Use
Certain medications may induce lymph node swelling under the armpit as a result of an allergic reaction. Vaccines can also lead to temporary side effects, including swelling of the lymph nodes in this area, as seen with vaccinations for diseases like measles, mumps, and rubella.
Cancer
The presence of a lump in the armpit area may be associated with various types of cancer, detailed as follows:
Breast Cancer
Breast cancer can present as a lump in the armpit, indicating the disease’s advance to the nearby lymph nodes. This occurrence can transpire before noticeable lumps form in the breast tissue.
Lymphoma
Lymphoma impacts the lymphatic system, which is essential for defending the body against infections. It may affect all components of the lymphatic system, including lymph nodes, spleen, thymus, and bone marrow.
Leukemia
Leukemia is a form of cancer that affects the blood and bone marrow, leading to uncontrolled growth of bone marrow cells.
Other Causes
The appearance of lumps under the armpit can also be attributed to several other factors:
Abscesses or Boils
Abscesses may form in the armpit area as a result of bacterial infections, often stemming from staphylococcal or streptococcal bacteria entering the body through tiny cuts from shaving.
Insect Bites
Insect bites, particularly mosquito bites, can cause a red swollen area to appear under the armpit, typically accompanied by intense itching.
Cysts
Cysts are usually formed due to injury, skin irritation from shaving, or ingrown hairs, often resulting in small fluid-filled sacs beneath the skin.
Blocked Milk Ducts
Blocked milk ducts can lead to milk accumulation, resulting in pressure and discomfort in the breast and armpit area.
Lipomas
Lipomas are among the most common benign tumors that develop just beneath the skin; they consist of fatty tissue and are generally harmless.
When to See a Doctor
Noticing a new lump can understandably provoke concern; however, it is important to recognize that not all lumps are harmful or painful. Medical evaluation, alongside additional testing as advised by a physician, can help determine the nature of the lump. Warning signs that may necessitate a doctor’s visit include:
- Gradual increase in lump size
- Lump persistence
- Lack of pain in the area of the lump
Article Summary
Lumps or swellings under the armpit typically result from abnormal tissue growth, and while most of these lumps are benign, some may be linked to serious health issues. A medical professional should evaluate any new lumps that arise.
Video on Armpit Lumps
Watch the video to view images of cancerous lumps under the armpit and learn how to manage them: