Inflammation of the lymph nodes is known as lymphadenitis. The condition usually is an indication of a bacterial infection but can also be due to virus or fungal infection. Additionally, this inflammation may be either generalized involving a number of lymph nodes; or limited to a few nodes in the area of a localized infection. The swollen glands are usually found near the site of an infection, tumor, or inflammation.
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. 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. Due to filtering functions, the lymph nodes are likely to be exposed to infectious agents. Once an infection is established, active migration of white blood cells towards affected lymph node(s) take place, resulting in the swelling of the nodes which are painful to touch.
The most common sign of lymphdenitis is enlarged or swollen lymph node(s) which can be accompanied by fever, loss of appetite, chills, weakness, rapid pulse and heavy perspiration. Abscesses may also be formed, specially when the cause is bacterial infection. Other symptoms will depend on the underlying cause of infection.