Definition of Lymphadenitis:

Lymphadenitis is an infection of the lymph nodes (also called lymph glands). It is a common complication of certain bacterial infections.

Causes, incidence, and risk factors:

The lymph system is a network of lymph nodes, lymph ducts, lymph vessels, and organs that produce and move a fluid called lymph from tissues to the bloodstream. For more information on this part of the body, see lymph system.

The lymph glands, or nodes, are small structures that filter the lymph fluid. There are many white blood cells in the lymph nodes to help fight infection.

Lymphadenitis occurs when the glands become enlarged by swelling (inflammation), usually in response to bacteria, viruses, or fungi. The swollen glands are usually found near the site of an infection, tumor, or inflammation.

Lymphadenitis may occur after skin infections or other infections caused by bacteria such as streptococcus or staphylococcus. Sometimes it is caused by rare infections such as tuberculosis or cat scratch disease (Bartonella).