Lymph nodes are small, bean-shaped structures that filter lymph fluid as part of the immune system. They trap harmful substances like bacteria, viruses, and damaged cells, including cancer cells, preventing their circulation. When lymph nodes encounter these foreign invaders, they can swell as immune cells multiply to fight off an infection or illness. While finding a swollen lymph node can be a source of concern, they are most often a sign of a common, non-serious condition.
Common Causes of Swollen Lymph Nodes
Most swollen lymph nodes result from common infections. Viral illnesses like the common cold, flu, mononucleosis, and strep throat are frequent culprits, causing nodes to enlarge as the immune system responds to pathogens. Bacterial infections, skin infections, or even dental abscesses can also lead to localized swelling in the nodes closest to the affected area. These nodes often feel tender or painful to the touch.
Inflammatory conditions also contribute to lymph node swelling. Autoimmune diseases such as rheumatoid arthritis or lupus can cause generalized lymphadenopathy, where nodes in multiple areas of the body may become enlarged. In these cases, the nodes typically remain soft and movable, reflecting their role in managing systemic inflammation rather than a localized threat. Allergies, though less common, can also trigger a temporary immune response that results in swollen lymph nodes.
Characteristics That Might Suggest Cancer
While most swollen lymph nodes are benign, certain characteristics suggest cancer. Cancerous nodes often feel hard, firm, or rubbery, and they may be fixed or matted together, meaning they do not move easily under the skin. Unlike benign nodes, which are often painful, cancerous nodes are frequently painless.
Size and duration are important indicators. Nodes persistently enlarged for several weeks, or growing beyond 1-2 centimeters, are concerning. Swelling in the supraclavicular area (above the collarbone) is also more concerning, even if small. Systemic symptoms like unexplained weight loss, drenching night sweats, or persistent fevers can accompany certain cancers like lymphoma.
When to Seek Medical Attention
Seek medical attention if a swollen lymph node shows concerning features. You should consult a healthcare professional if a node remains enlarged for more than two to four weeks or continues to grow in size. Nodes that feel hard, fixed, or are painless should also prompt an evaluation, as these characteristics can be more suggestive of malignancy.
A doctor’s visit is also warranted if the swollen lymph node is accompanied by other unexplained symptoms. These include persistent fever, drenching night sweats, unexplained weight loss, or prolonged fatigue. Furthermore, if there is no obvious infection or injury in the area drained by the swollen node, or if swelling occurs in less common locations such as above the collarbone or in the armpit without a clear local cause, medical assessment is recommended. Medical advice is important for accurate assessment and diagnosis.
Medical Evaluation and Diagnosis
When a swollen lymph node requires medical attention, a healthcare professional conducts a thorough evaluation. This begins with a physical examination to assess the node’s size, tenderness, texture, and mobility. They will also inquire about your medical history, including recent illnesses, symptoms, travel, medications, and family history.
Diagnostic steps may involve blood tests to detect infection, inflammation, or other markers. Imaging studies, such as an ultrasound, CT scan, or MRI, might be ordered to provide a more detailed view of the lymph nodes and surrounding tissues, helping to identify any abnormal growths or patterns. A definitive diagnosis often requires a lymph node biopsy, where a tissue sample is removed for microscopic examination. This helps identify the cause of swelling, confirming if it is benign or malignant.