Lymph nodes are part of the immune system of the body and are located in different regions throughout the body. Lymph nodes purify lymph (a fluid that flows through lymphatic system) as they flow through lymph nodes, by filtering viruses, bacteria and other foreign substances. The residue thus obtained is destroyed by lymphocytes which are special white blood cells. Lymph nodes may be as small as a pin head or may be as large as a bean. They are found isolated and in groups. Most of the lymph nodes cannot be felt and they are neither tender nor painful. Lymph nodes in the groin, neck and arms can be felt.
Lymph nodes in a certain locations become swollen, when a tumor or infection or injury occurs in the nearby area. Groin, neck and underarms are the common areas for swollen lymph nodes. When Lymph nodes in two or more areas swell, it is known as generalized lymphadenopathy. Viral illness like measles and mumps, bacterial illness like strep throat, side effects of certain medicines, cancers like leukemia, AIDs, sexually transmitted diseases like syphilis etc are the causes for generalized lymphadenopathy. Cancers that originate in the lymph nodes such as leukemia and cancers that are originate on other organs and that spread to lymph nodes can also be the cause for the swelling of lymph nodes. Swollen lymph nodes need not always be a symptom of an underlying disease. For example small swelling less than 1 cm thickness found under the jaw and similar swelling less than 2 cms thickness found in children and young adults may be normal.
Treatment
Treatment for swollen lymph nodes is based on the cause for the formation of swollen lymph nodes. Swollen lymph nodes caused by viral illness go by its own as the illness disappears. Swollen lymph nodes caused by bacterial infection can be treated with antibiotics. If the swelling did not decrease or vanish within a period of one month, it has to be brought to the notice of your physician. In children the lymph nodes may remain swollen for a long time even after the illness causing it has subsided.