Lymph nodes are small, bean-shaped glands found throughout the body, forming a part of the immune system. A swollen lymph node is common and often indicates a harmless, temporary response to an underlying condition, rather than a serious issue.
The Role of Lymph Nodes in Your Body
Lymph nodes are distributed extensively throughout the body, acting as filters within the lymphatic system. They are small, typically ranging from a few millimeters to about 1-2 centimeters in size, and are connected by a network of lymphatic vessels. These nodes are particularly concentrated in areas such as the neck, armpits (axillae), and groin (inguinal region), where they can sometimes be felt just beneath the skin.
The primary function of lymph nodes involves filtering lymph fluid, which circulates through the body, collecting waste products and foreign materials. As lymph fluid passes through the nodes, specialized immune cells called lymphocytes trap and destroy harmful invaders like bacteria, viruses, and abnormal cells. When the body encounters an infection or other immune challenge, these nodes can become enlarged as immune cells multiply to fight off the threat.
Common Causes of Benign Swollen Lymph Nodes
Lymph nodes frequently swell in response to a variety of common, non-serious conditions, indicating that the immune system is actively working. Infections are among the most frequent culprits, causing the nodes to enlarge as they filter pathogens. For example, a common cold, strep throat, or an ear infection can lead to swollen lymph nodes in the neck. Skin infections, such as cellulitis or an abscess near a node, can also cause localized swelling, as can dental infections like an abscessed tooth.
Beyond infections, certain inflammatory conditions can also trigger benign lymph node enlargement. Conditions such as rheumatoid arthritis or lupus, which involve widespread inflammation in the body, may cause nodes to swell as part of the systemic immune response. Occasionally, reactions to vaccinations can lead to temporary swelling in nearby lymph nodes. Some medications might induce a benign reactive swelling in the lymph nodes as a side effect.
Distinguishing Benign from Concerning Swelling
A benign swollen lymph node feels soft or rubbery, is easily movable under the skin, and may be tender or painful when touched. This tenderness often indicates inflammation or an active immune response, and such nodes usually decrease in size once the underlying cause, like an infection, resolves. The size of a benign node can vary but often remains under 1 to 2 centimeters.
In contrast, certain features of a swollen lymph node might suggest a need for medical attention. Nodes that feel hard, are fixed to underlying tissues, or are painless and continue to grow, could be concerning. Swelling that persists for more than two to four weeks without an obvious cause, or that grows rapidly, also warrants professional evaluation. Additional symptoms such as unexplained weight loss, night sweats, or a persistent fever accompanying the swollen node should prompt consultation with a healthcare provider.
How Benign Lymph Nodes Are Evaluated
When a swollen lymph node is identified, a healthcare provider begins with a physical examination. During this examination, the doctor will feel the size, texture, mobility, and tenderness of the swollen node, and check other lymph node areas. The evaluation also involves taking a patient history, inquiring about recent infections, injuries, medications, or any other accompanying symptoms.
Based on the physical examination and patient history, the provider may order further diagnostic tests. Blood tests might be ordered to check for signs of infection, inflammation, or other conditions. Sometimes, imaging studies like an ultrasound may be used to visualize the node’s internal structure and surrounding tissues. Rarely, if there is persistent concern or atypical features, a biopsy of the lymph node might be performed to examine a tissue sample under a microscope to determine the exact cause of the swelling.