What to Do About Swollen Lymph Nodes Under the Arm
Swollen lymph nodes under the arm, also known as axillary lymphadenopathy, can be caused by a wide range of factors — from minor infections to more serious underlying conditions. Because the causes vary significantly, proper diagnosis is essential before any treatment plan can be established. It's important not to jump to conclusions, but equally crucial not to ignore persistent swelling.
Common Causes of Axillary Lymph Node Enlargement
Lymph nodes act as filters in the body's immune system, trapping bacteria, viruses, and even cancer cells. When they become enlarged under the arm, it often indicates that the body is responding to an infection or inflammation nearby.
Benign (Non-Cancerous) Causes
One of the most frequent non-serious causes is acute mastitis, particularly in breastfeeding women. This condition occurs when breast tissue becomes infected, leading to pain, redness, and swollen lymph nodes in the armpit. In such cases, prompt antibiotic treatment usually resolves both the infection and the lymph node swelling.
Other benign triggers include skin infections on the arm or chest, routine vaccinations (such as those for typhoid or certain COVID-19 vaccines), or even minor injuries that introduce bacteria into the skin. These typically resolve on their own or with basic medical care.
Serious Conditions That May Cause Swelling
While many cases are harmless, swollen axillary lymph nodes can sometimes signal something more concerning — especially breast cancer. Cancer cells can spread to the lymph nodes under the arm, causing them to enlarge. This makes swollen lymph nodes a potential early warning sign, particularly if they're hard, painless, and don't move easily under the skin.
In rare cases, other malignancies like lymphoma or metastatic cancers from other parts of the body may also present with armpit lymph node swelling. That's why unexplained, persistent enlargement lasting more than two weeks warrants a thorough medical evaluation.
How Is the Condition Diagnosed?
A healthcare provider will typically begin with a physical exam and detailed medical history. Imaging tests such as ultrasound or mammography may be used, and in some cases, a fine-needle aspiration or biopsy might be necessary to analyze the lymph node tissue.
Treatment Options Based on the Underlying Cause
If the swelling is due to an infection, antibiotics or anti-inflammatory medications are usually effective. However, if breast cancer is confirmed, a comprehensive treatment strategy is required.
Standard treatments for cancer-related lymph node involvement include:
- Surgical removal of the tumor and affected lymph nodes (lymphadenectomy)
- Radiation therapy to target remaining cancer cells
- Chemotherapy to shrink tumors and prevent recurrence
- Targeted therapies or hormone treatments, depending on the cancer type
Early detection greatly improves outcomes, so individuals noticing new lumps or persistent swelling under the arm should seek medical advice without delay.
When to See a Doctor
You should consult a healthcare professional if the swelling:
- Persists for more than two weeks
- Is accompanied by fever, night sweats, or unexplained weight loss
- Feels hard, fixed in place, or rapidly growing
- Occurs alongside changes in the breast, such as dimpling, nipple discharge, or skin texture changes
Understanding the root cause behind swollen lymph nodes under the arm is key to effective treatment. While many causes are minor and temporary, recognizing warning signs of serious illness allows for timely intervention and better health outcomes.