Lymph nodes are small, bean-shaped structures crucial to the immune system. They act as filters, trapping foreign substances like viruses, bacteria, and abnormal cells. Allergies, an immune system response to typically harmless substances, can cause these nodes to swell.
Allergic Reactions and Lymph Node Swelling
When the body encounters an allergen, such as pollen or pet dander, the immune system may overreact, identifying the harmless substance as a threat. This triggers the release of chemicals like histamine and the activation of various immune cells. Lymph nodes serve as central stations where immune cells gather and multiply to combat these perceived invaders. This rapid increase in immune cell activity and proliferation within the nodes causes them to enlarge and become noticeable.
Typically, the affected lymph nodes are located near the site of the allergic reaction. For instance, seasonal allergies affecting the nasal passages might cause swelling in the lymph nodes of the neck or under the jaw. Similarly, skin reactions from allergies could lead to localized swelling in nearby lymph nodes. This enlargement is generally temporary and tends to subside once the allergen is removed or the allergic reaction is brought under control.
Common Causes of Lymph Node Swelling
While allergies can sometimes cause lymph nodes to swell, infections are a more frequent reason for this occurrence. Viral infections, such as the common cold, flu, or mononucleosis, are common culprits that prompt lymph nodes to enlarge as they fight off pathogens. Bacterial infections, including strep throat, ear infections, or skin infections, can also lead to noticeable swelling.
Inflammation stemming from various conditions, not necessarily infections, can also result in lymph node enlargement. Less commonly, autoimmune diseases, where the immune system mistakenly attacks the body’s own tissues, or certain types of cancer, can be underlying causes of persistent lymph node swelling.
When to Seek Medical Attention
While lymph nodes swollen due to allergies usually resolve on their own, certain characteristics warrant medical evaluation. It is advisable to consult a healthcare professional if the swollen lymph nodes have no clear cause or continue to enlarge. Swelling that persists for more than two to four weeks should also be assessed by a doctor.
Other concerning signs include lymph nodes that feel very hard, are fixed in place, or grow rapidly. If the swelling is accompanied by symptoms such as unexplained fever, night sweats, significant weight loss, or persistent fatigue, medical attention is recommended. Redness, tenderness, or warmth around the lymph nodes could indicate an infection.