Lymphadenitis - INFLAMMATION or INFECTION of LYMPH nodes. Lymphadenitis characterizes systemic infections such as infectious mononucleosis and regional infections such as SEXUALLY TRANSMITTED DISEASES (STDS). It may affect any lymph nodes in the body though is most noticeable when it affects LYMPH NODE clusters near the surface of the SKIN, such as in the neck, axillae (underarms), and groin (inguinal).
The typical symptoms of lymphadenitis are palpable lymph nodes that may range in size from that of a small pea to that of a large marble. The swellings are often painful, and the skin above the area may be reddened (erythematous) and warm to the touch when infection of the lymph nodes themselves is the cause. Diagnosis may require lymph node biopsy when there are no clear signs of infection or when lymphadenitis continues beyond six weeks.
Lymphadenitis without signs of infection may indicate cancer, either affecting the lymph structures (LYMPHOMA) or in METASTASIS from any location in the body. Pathogens or cancer cells traveling through the lymph can initiate such a massive activation of phagocytic response that the resulting action of macrophages and lymphocytes overwhelms the lymph nodes with cellular debris faster than the lymph can carry it away.
See also LYMPH VESSELS; MONONUCLEAR PHAGOCYTE SYSTEM; MONONUCLEOSIS, INFECTIOUS; PHAGOCYTOSIS.
Resource: Facts On File Encyclopedia Of Health And Medicine
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