Recently, Dr. Sabrina Felson reviewed in WebMD one of the body’s other circulating systems, the lymphatic system. Lymph nodes are your immune system’s first line of defense, protecting you from things like bacteria or viruses that could make you sick.
The human body has hundreds of the small, round or bean-shaped glands. Most are spread out, but some are found in groups in a few major places including the neck, under the arm and in the chest, belly and groin. They might be felt in those areas as little bumps.
Lymph nodes are part of your lymphatic system. Along with your spleen, tonsils and adenoids, they help you fight off illness and infections.
Lymph nodes are connected to one another by lymph vessels (tubes that run through your body like veins). They carry lymph fluid — a clear, watery liquid that passes through the nodes. As the fluid flows through, cells called lymphocytes help protect you from harmful germs. There are two kinds of lymphocytes — B-lymphocytes (or B-cells) and T-lymphocytes (or T-cells).
• B-cells make antibodies that attach to germs and let your immune system know they need to be killed off.
• T-cells have a couple of jobs. Some destroy germs while others keep track of immune cells. They let your body know when to make more of certain kinds and less of others.
Lymph fluid also carries protein, waste, cellular debris (what’s left after a cell dies), bacteria, viruses and excess fat that are filtered by the lymphatic system before it’s dumped back into the bloodstream.
With an illness or an infection, your lymph nodes can swell. (This usually happens only in one area at a time.) It’s a sign that more lymphocytes are in action than usual, trying to kill off germs. Most often this is noticed in the glands in your neck.
Many things can make your lymph nodes swell. It might be something like a cold or the flu, an ear infection or an abscessed tooth. Much less often, it can be a sign of something more serious, like tuberculosis or cancer.
Nearly all children will get lymphadenopathy (swollen lymph nodes) at some time. That’s because enlarged glands often occur with viral or bacterial infections like colds, the flu or strep throat. Enlarged lymph nodes are often near the source of infection, so their location can help find out the cause.
For example, a baby with a scalp infection may have enlarged lymph nodes at the back of the neck. Swollen lymph nodes around the jaw may be a sign of an infection in the teeth or mouth. Lymphadenopathy also may affect lymph nodes throughout the body. This is common in some viral illnesses such as mono (infectious mononucleosis) or chickenpox.
If a lymph node is growing bigger, tender or inflamed or hard and seems fixed in place, call your health care provider. Most swollen nodes are in response to an infection but not all.