Causes of Swollen Lymph Nodes in the Armpit: What You Need to Know
Swollen lymph nodes under the arm, also known as axillary lymphadenopathy, are a common condition that can stem from a variety of underlying causes. These small, bean-shaped glands play a crucial role in the body's immune defense by filtering harmful substances and helping fight infections. When they become enlarged, it often signals that the body is responding to an internal or localized issue.
Common Causes of Axillary Lymph Node Enlargement
Understanding the potential reasons behind swollen armpit lymph nodes is essential for timely diagnosis and appropriate treatment. While most cases are benign and resolve on their own, some may indicate more serious health concerns.
1. Infections and Localized Inflammation
One of the most frequent causes of swollen lymph nodes in the armpit is infection or inflammation in nearby tissues. Conditions such as breast infections (mastitis), skin infections like folliculitis, or even minor cuts and abrasions in the arm or upper torso can trigger an immune response. The lymph nodes react by swelling as they work to filter out bacteria and other pathogens. This type of swelling is typically accompanied by symptoms such as redness, tenderness, warmth in the skin, and sometimes fever.
In individuals who shave their underarms regularly, ingrown hairs or infected hair follicles can also lead to localized irritation and subsequent lymph node enlargement. Maintaining proper hygiene and avoiding aggressive hair removal techniques may help reduce the risk.
2. Hormonal Changes and Benign Breast Conditions
Non-cancerous breast conditions, such as fibrocystic breast changes or hormonal fluctuations during the menstrual cycle, can cause breast tissue discomfort and, in some cases, lead to mild lymph node swelling. Many women experience cyclical breast tenderness and lumpiness, particularly before menstruation, which may be associated with reactive lymph nodes in the axilla.
While these changes are usually harmless, persistent discomfort can be managed with over-the-counter pain relievers, supportive bras, and lifestyle adjustments such as reducing caffeine intake. If symptoms worsen or do not follow a predictable pattern, medical evaluation is recommended.
3. Malignant Conditions and Cancer Metastasis
Although less common, swollen armpit lymph nodes can be a sign of a more serious condition, including certain types of cancer. Breast cancer is one of the primary concerns, as cancer cells often spread to the axillary lymph nodes first. Similarly, cancers such as lymphoma, melanoma, or even thyroid cancer can metastasize to this region.
In these cases, the lymph nodes tend to be hard, fixed in place, and usually painless. Other warning signs may include unexplained weight loss, night sweats, fatigue, or changes in breast appearance such as dimpling or nipple discharge.
Diagnosis and When to Seek Medical Attention
If you notice persistent swelling in your armpit—especially if it lasts longer than two weeks, increases in size, or occurs without a clear cause—it's important to consult a healthcare provider. Early detection significantly improves outcomes, particularly when cancer is involved.
A diagnostic ultrasound (B-mode ultrasound) is commonly used to evaluate the structure, size, and blood flow within the lymph nodes. This non-invasive imaging technique helps differentiate between benign inflammatory changes and potentially malignant growths. In some cases, further tests such as fine-needle aspiration, biopsy, or blood work may be necessary to confirm a diagnosis.
Final Thoughts
While swollen lymph nodes in the armpit are often a temporary and harmless response to infection or inflammation, they should never be ignored—especially if they persist or are accompanied by other concerning symptoms. Staying informed and proactive about your health allows for earlier intervention and better overall outcomes. Always seek professional medical advice if you're uncertain about any physical changes in your body.