Swollen Lymph Nodes in the Armpit: Causes, Symptoms, and When to Seek Care

Understanding the causes, symptoms, and diagnostic clues of swollen lymph nodes in your armpit for better health awareness.

By Sneha Tete, Integrated MA, Certified Relationship Coach

Created on Sep 25, 2025

Understanding the causes, symptoms, and diagnostic clues of swollen lymph nodes in your armpit for better health awareness.

Swollen Lymph Nodes in the Armpit: Understanding the Signs, Causes, and Care

Swollen lymph nodes in the armpit, medically called axillary lymphadenopathy, are a common clinical sign that can arise in response to various triggers, including infections, immune system conditions, or even cancers. While this symptom is often benign and temporary, sometimes it signals a more serious underlying issue. Recognizing the possible causes and knowing when to seek medical attention is important for your health and overall peace of mind.

What Are Lymph Nodes and Why Do They Swell?

Lymph nodes are small, bean-shaped glands that act as filters in your immune system. They trap and destroy bacteria, viruses, and other unwanted substances. The armpit—or axillary—region contains clusters of these lymph nodes. When you notice swelling in your armpit, it means that these lymph nodes have become enlarged due to increased activity or inflammation in response to a problem nearby or affecting your immune system.

Common Causes of Swollen Lymph Nodes in the Armpit

Enlarged axillary lymph nodes often reflect a local or systemic health condition. The most frequent causes include:

Viral infections (such as the flu, common cold, mononucleosis, herpes, rubella, HIV)
Bacterial infections (commonly due to skin infections, Staphylococcus, Streptococcus, or more serious bacteria)
Immune system disorders (including lupus, rheumatoid arthritis, sarcoidosis)
Cancer (breast cancer, lymphoma, melanoma, leukemia)
Local skin or sweat gland inflammation (such as hidradenitis suppurativa or infected hair follicles)
Vaccine reactions
Autoimmune diseases
Other rare infections (like tuberculosis)

Overview Table: Key Causes of Axillary Lymph Node Swelling

Category	Examples	Typical Features
Viral infections	Flu, common cold, herpes, mononucleosis, HIV	Multiple nodes, often with fever, fatigue
Bacterial infections	Cellulitis, boils, abscess, Staph/Strep	Warmth, redness, pain over node; may have pus
Immune disorders	Lupus, rheumatoid arthritis, sarcoidosis	Multiple areas affected, joint/muscle pain
Cancer	Breast cancer, lymphoma, melanoma	Usually firm, fixed, painless lump
Sweat gland inflammation	Hidradenitis suppurativa, folliculitis	Hard, tender, red lump; skin changes
Vaccine or medication reaction	Recent immunization (flu, COVID-19, etc.)	Transient, mild swelling without other symptoms

Symptoms: What Do Swollen Lymph Nodes in the Armpit Feel and Look Like?

When a lymph node in the armpit swells, you might notice one or more of the following:

A firm or rubbery lump under the skin in your armpit (may be movable or fixed)
Pain or tenderness—although not all swollen nodes are painful
Redness or warmth over the lump, especially if an infection is present
Size variation: Swollen nodes may range from pea-sized to as large as a grape
Multiple lumps: Sometimes, more than one node is enlarged
Other systemic symptoms, such as fever, night sweats, unexplained weight loss, or fatigue (particularly with infections or systemic illnesses)

The appearance and associated symptoms often offer clues about the cause and urgency of the problem.

Pictures of Swollen Lymph Nodes in the Armpit

While images are helpful for understanding how lymph node swelling may appear, it’s important to note that lumps in the armpit can vary greatly, from subtly raised bumps to obvious enlargements with skin changes. Visuals may show:

Discrete, round lumps beneath the skin
Reddened, inflamed skin if infection or abscess is present
Clusters of lumps or isolated swellings
Visible drainage or pus in the case of boils or abscesses

How Is the Cause Diagnosed?

A healthcare provider will evaluate swollen lymph nodes in the armpit through several steps:

Medical history: Recent infections, injuries, surgeries, vaccinations, cancer, or immune disorders
Physical exam: Assessing location, size, tenderness, and firmness of the nodes
Laboratory tests: Blood tests to screen for infections or systemic conditions
Imaging: Ultrasound, X-ray, or CT scans to examine deeper nodes or surrounding tissues
Biopsy: Sometimes required to rule out cancer or determine the specific cause

Prompt diagnosis is important, especially when signs suggest a more serious problem.

When Should You Seek Medical Attention?

In most cases, lymph node swelling resolves as the body recovers from a minor infection. However, consult a doctor promptly if you notice:

Swollen lymph node persists for more than two weeks
The lump continues to increase in size
The node is very hard, fixed, or painless (may indicate cancer)
You have unexplained fever, night sweats, or weight loss
The area is red, hot, or draining pus
You have a history of cancer
There is difficulty moving your arm or new neurological symptoms

Treatment Options for Swollen Armpit Lymph Nodes

Treatment depends on the cause. Some common interventions include:

Viral infections: Rest, fluids, and time; severe viral illnesses like HIV require specific antiviral medication
Bacterial infections: Antibiotics, pain relievers, and sometimes minor surgery to drain abscesses
Immune disorders: Anti-inflammatory medications, immunosuppressants, supportive therapy
Cancer: Oncology consultation, surgery, chemotherapy, radiation therapy, or targeted treatment as appropriate
Sweat gland conditions (e.g., hidradenitis suppurativa): Antibiotics, warm compresses, corticosteroids, and sometimes surgical intervention
Benign/reactive swelling: Observation, as nodes often return to normal size when the triggering cause resolves

Always follow your healthcare provider’s guidance for the best outcomes. Self-treatment is not recommended for unexplained armpit swelling.

Risk Factors and Prevention

Some people are more prone to developing swollen armpit lymph nodes, including:

Individuals with frequent skin infections or trauma in the armpit or upper arm
People with autoimmune diseases or compromised immune function
Those undergoing cancer treatment or with a past history of cancer
Anyone with recent vaccinations or exposure to new medications

Prevention focuses on:

Practicing good hygiene
Protecting skin from infection and injury
Seeking timely care for infections
Managing chronic health conditions as advised by your doctor

Potential Complications

If left untreated, swollen lymph nodes due to infection may lead to:

Abscess formation: Localized collection of pus
Spread of infection: To deeper layers or bloodstream (sepsis)
Tissue damage: Persistent inflammation can scar the area
Missed cancer diagnosis: Delaying evaluation in rare but serious cases

Frequently Asked Questions (FAQ)

What do swollen lymph nodes in the armpit feel like?

They usually present as a soft, firm, or rubbery lump. It may be tender to touch, moveable or, rarely, fixed and hard if cancerous.

How long do swollen armpit lymph nodes take to heal?

Most cases caused by mild infections resolve within 1–3 weeks. Nodes enlarged due to more serious conditions may persist longer and require specific treatment.

Can a swollen lymph node in the armpit be cancer?

Yes, but this is much less common than infections. Cancer-associated nodes are often hard, fixed, painless, and grow progressively. Early medical assessment is important for diagnosis.

Should I worry if one armpit node is swollen and the other is not?

Unilateral swelling is more often due to local infection or inflammation. However, if the swelling does not resolve or worsens, see your healthcare provider.

Is it normal to have swollen lymph nodes after a vaccine?

Yes, temporary swelling is a common reaction after certain vaccinations, such as COVID-19 or flu shots, and usually resolves in a few days to weeks.

Key Takeaways

Swollen armpit lymph nodes are usually caused by infection, inflammation, immune response, or, less commonly, cancer
Accompanying symptoms and persistent, hard, or painless nodes require prompt medical attention
Most cases resolve with rest or targeted treatment for the underlying cause
Never ignore or self-treat persistent or enlarging lumps in the armpit

If you notice an abnormal lump or swelling in your armpit, monitor for other symptoms, take note of any recent illnesses or procedures, and reach out to a medical professional when in doubt. Early diagnosis and proper care can make a significant difference in your health and wellbeing.

References

Author

Sneha TeteBeauty & Lifestyle Writer

Sneha is a relationships and lifestyle writer with a strong foundation in applied linguistics and certified training in relationship coaching. She brings over five years of writing experience to thebridalbox, crafting thoughtful, research-driven content that empowers readers to build healthier relationships, boost emotional well-being, and embrace holistic living.

Read full bio of Sneha Tete