Lymphadenopathy refers to the enlargement of one or more lymph nodes, the bean-shaped glands found in the neck, armpits, chest, groin, and abdomen. Lymphadenopathy may occur in just one part of the body, in which case it is referred to as “localized” or it may be present in two or more body areas, in which case it is referred to as “generalized.” The condition most commonly affects nodes in the neck (cervical lymph nodes).
Substances present in the interstitial place including infectious microorganisms, antigens, and cancer cells enter the lymphatic vessels to form lymphatic fluid. This fluid is filtered by the lymph nodes, which removes these materials as the fluid flows towards the central venous circulation. This filtering process presents antigens to lymphocytes present inside the nodes. The response lymphocytes have to this antigen presentation involves cellular proliferation, which can lead to node enlargement. This is referred to as reactive lymphadenopathy.
Microorganisms can infect nodes directly and cause a condition called lymphadenitis, which describes lymphadenopathy accompanied by pain and other signs of inflammation such as redness and tenderness. Lymphadenopathy can also be caused by cancer cells lodging in the nodes and proliferating, making the nodes grow larger.
Infection is the most common cause of lymphadenopathy. The lymphatic system is a component of the immune system, which is designed to fight infection. As cells and fluid accumulate in the lymph nodes when infection is present and cause them to enlarge, the location of the lymph nodes can be used to help establish the cause of infection. For example, if a patient has a scalp infection, the lymph nodes at the back of the neck may be enlarged. If infection is present in the mouth or teeth, lymph nodes around the jaw area may be enlarged. However, lymphadenopathy may occur throughout the body, which is common in the case of some viral infections such as chickenpox. Lymphadenopathy that occurs in response to a viral infection usually resolves within one to two weeks.
More serious causes of lymphadenopathy include some cancers, which may originate in the lymph nodes or spread to them from other areas of the body. Lymphadenopathy as a result of cancer is uncommon, with one study showing that of more than 2500 patients who presented with lymphadenopathy, cancer was the cause in only 1%.
It is normal to be able to feel lymph nodes as small lumps under the skin, but if infection or another problem is present, the nodes may be enlarged and cause pain, tenderness, redness, and warmth. Depending on the cause of the condition, other symptoms may be present, including:
- Body aches
- Loss of appetite
- Respiratory symptoms such as cough or congestion
Lymphadenopathy is often harmless and resolves independently, without the need for treatment. If treatment is used, it is targeted at the cause of the lymphadenopathy, rather than the adenopathy itself.