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Swollen lymph nodes, or enlarged lymph glands, can be caused due to various reasons. Lymph glands, also referred to as lymph nodes, form a part the lymphatic system, which aid the body’s immune system and protect the body against infection. Hence, when the lymph glands get swollen, it could signify an infection.
Lymph nodes occur all over the body, although they bunch together in groups in certain parts of the body, such as the neck, the armpits and the groin. These are joined together by channels, which form a network, through which is carried a fluid called lymph, which finally is drained into the bloodstream. Lymph actually contains lymphocytes, or white blood cells and chyle. Enlarged lymph nodes usually occur in the groin, the armpits, in the neck, and under the chin.
The symptoms of swollen lymph nodes depend upon both the location and cause of the enlargement.
Patients may experience symptoms of an upper respiratory infection (runny nose, sore throat, fever) and feel slightly tender nodes under the skin around the ears, under the chin, or on the upper part of the neck.
Sometimes there may be a skin infection or redness and one may feel an enlarged node in the vicinity tracking toward the heart.
Swelling of a lymph node located deep inside the body may have different consequences from swelling of those just under the skin. The blockage in the flow of lymph from swelling in a deeper node may cause a swelling of a limb or, for example, swelling of lymph nodes in the lung could cause a chronic cough, even though you would not be able to feel a swollen node in that location.
Some infections (mononucleosis or "mono," HIV, and fungal or parasitic infections) may cause generalized swelling of lymph nodes throughout the body.
Some immune disorders, such as lupus or rheumatoid arthritis, may also cause generalized lymph node swelling.
Rarely, a person may have a node or group of nodes that grows rapidly and becomes hard and can not be easily moved around under the skin.
A lymph node is a small, round or bean-shaped cluster of cells covered by a capsule of connective tissue. The cells are a combination of lymphocytes — which produce protein particles that capture invaders, such as viruses — and macrophages, which break down the captured material. Lymphocytes and macrophages filter your lymphatic fluid as it travels through your body and protect you by destroying invaders.
Lymph nodes are located in groups, and each group drains a specific area of your body. You may be more likely to notice swelling in certain areas, such as in the lymph nodes in your neck, under your chin, in your armpits and in your groin. The site of the swollen lymph nodes may help identify the underlying cause.
The most common cause of swollen lymph nodes is an infection, particularly a viral infection, such as the common cold. However, there are other types of infection, including parasitic and bacterial, and other possible causes of swollen lymph nodes. They include:
Strep throat
Measles
Ear infections
Infected (abscessed) tooth
Mononucleosis
Skin or wound infections, such as cellulitis or erysipelas
Human immunodeficiency virus (HIV) — the virus that causes AIDS
Tuberculosis
Certain sexually transmitted diseases, such as syphilis
Toxoplasmosis — a parasitic infection resulting from contact with the feces of an infected cat or eating undercooked meat
Cat scratch fever — a bacterial infection from a cat scratch or bite
Lupus — a chronic inflammatory disease that can target your joints, skin, kidneys, blood cells, heart and lungs
Rheumatoid arthritis — a chronic inflammatory disease that targets the tissue that lines your joints (synovium)
Lymphoma — cancer that originates in your lymphatic system
Leukemia — cancer of your body's blood-forming tissue, including your bone marrow and lymphatic system
Other cancers that have spread (metastasized) to lymph nodes
Other possible, but rare causes include certain medications, such as the anti-seizure medication phenytoin (Dilantin), and preventive medications for malaria.