A lymph node is a small, round or bean-shaped cluster of cells covered by a capsule of connective t...
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. Other possible causes of swollen lymph nodes include:
Infected (abscessed) tooth
Skin or wound infections, such as cellulitis
Human immunodeficiency virus (HIV) — the virus that causes AIDS