Causes of Swollen Lymph Nodes Under the Arm: What You Need to Know
Understanding Axillary Lymph Node Enlargement
Swollen lymph nodes under the arm, also known as axillary lymphadenopathy, can be a sign of various underlying health conditions. While it's often linked to minor infections, persistent or unexplained swelling may indicate more serious medical issues. Recognizing the potential causes is essential for timely diagnosis and appropriate treatment.
Common Causes of Axillary Lymph Node Swelling
Lymph nodes act as filters in your body's immune system, trapping bacteria, viruses, and even cancer cells. When they detect harmful agents, they can become enlarged. Below are some of the most frequent reasons for swollen lymph nodes in the armpit area.
1. Localized Infections
One of the most common causes is a localized skin infection, such as folliculitis or an abscess near the armpit. Bacterial infections like staphylococcus or streptococcus can trigger inflammation in nearby lymph nodes. These infections typically cause tender, warm, and slightly movable swollen nodes that usually resolve with proper treatment, such as antibiotics or drainage.
2. Mastitis and Breast Infections
Mastitis, particularly common in breastfeeding women, occurs when breast tissue becomes inflamed—often due to a blocked milk duct or bacterial infection. This condition frequently leads to swollen lymph nodes under the arm on the affected side. Symptoms may include breast pain, redness, fever, and flu-like discomfort. Prompt medical care can prevent complications.
3. Blood and Immune System Disorders
Certain systemic diseases, including leukemia and lymphoma, can manifest as enlarged axillary lymph nodes. These cancers affect the lymphatic system or bone marrow, leading to painless, firm, and sometimes rapidly growing lymph nodes. If swelling persists without signs of infection, further diagnostic tests such as blood work or biopsy may be necessary.
4. Tuberculosis of the Lymph Nodes (Lymphadenitis)
In regions with limited healthcare access, mycobacterium tuberculosis can spread to the lymph nodes, causing a condition called scrofula or tuberculous lymphadenitis. This often results in chronic swelling, possible skin breakdown, and systemic symptoms like night sweats and weight loss. Early detection and long-term antibiotic therapy are crucial for recovery.
5. Metastatic Cancer and Lymph Node Involvement
Cancer spread (metastasis) is a serious concern when axillary lymph nodes are enlarged. Breast cancer is especially known to metastasize early to the underarm lymph nodes. However, other malignancies such as lung cancer, melanoma, or abdominal tumors may also spread through the lymphatic system. In these cases, the nodes tend to be hard, fixed in place, and non-tender.
When to Seek Medical Attention
While occasional swelling due to minor infections is normal, you should consult a healthcare provider if:
- The lump persists for more than two weeks
- It continues to grow or feels hard and immovable
- You experience unexplained weight loss, fever, or night sweats
- There are changes in the overlying skin, such as redness or ulceration
Diagnosis and Next Steps
Doctors may use physical exams, imaging (like ultrasound or MRI), blood tests, or a biopsy to determine the root cause. Early evaluation improves outcomes, especially when serious conditions like cancer or chronic infections are involved.
Staying informed about your body and seeking prompt medical advice can make a significant difference in managing axillary lymph node swelling effectively.