Lymphadenitis is the medical term for an infection in one or more lymph nodes. Lymph nodes are filled with white blood cells that help your body fight off infections. When lymph nodes become infected, it's usually because an infection started somewhere else in your body.
You have about 600 lymph nodes in your body, but normal lymph nodes may only be felt below your jaw, under your arms, and in your groin area.
A normal lymph node is small and firm. When lymph nodes become infected, they usually increase in size and may be felt in other areas of your body during a physical examination.
Infections that spread to lymph nodes are usually caused by bacteria, viruses, or fungi. It is important to learn how the infection spread into your lymph nodes so that the right treatment can be started.
Lymphadenitis can be one of two types:
Localized lymphadenitis. This is the most common type. Localized lymphadenitis involves one or just a few nodes that are close to the area where the infection started. For example, nodes enlarged because of a tonsil infection may be felt in the neck area.
Generalized lymphadenitis. This type of lymph node infection occurs in two or more lymph node groups and may be caused by an infection that spreads through the bloodstream or another illness that affects the whole body.
The main symptom of lymphadenitis is enlarged lymph nodes. A lymph node is considered enlarged if it is about one-half inch wide. Symptoms caused by an infected lymph node or group of nodes may include:
Nodes that increase in size suddenly
Nodes that are painful to touch
Nodes that are soft or matted together
Redness or red streaking of the skin over nodes
Nodes that are filled with pus (an abscess)
Fluid that drains from the nodes to the skin
Lymphadenitis may also cause symptoms related to the underlying infection, such as a sore throat, fever, night sweats, fatigue, or weight loss.
If you have lymphadenitis, the most important parts of your diagnosis are usually your history and the physical exam done by your doctor. You may be asked about symptoms you're feeling, such as chills and fever, any recent travel, any breaks in your skin, and recent contact with cats or other animals. Then, during the physical exam, your doctor will look for signs of infection near the enlarged lymph nodes.
These tests may be needed to help make the diagnosis:
Blood tests to look for infection
Taking a piece of the lymph node or fluid from inside the lymph node to study under a microscope
Placing fluid from the lymph node into a culture to see what type of germs grow
The exact type of treatment depends on what type of infection has spread into your lymph nodes. Once an infection has spread into some lymph nodes, it can spread quickly to others and to other parts of your body, so it's important to find the cause of the infection and start treatment quickly.
Treatment for lymphadenitis may include:
Antibiotics given by mouth or injection to fight an infection caused by bacteria
Medication to control pain and fever
Medication to reduce swelling
Surgery to drain a lymph node that has filled with pus
The best way to prevent lymphadenitis is to see your doctor at the first sign of any infection or if you notice a tender swelling that feels like a little lump just beneath your skin. Make sure to cleanse and use antiseptic on any scratches or breaks in your skin and always practice good hygiene.
Take all your medications exactly as prescribed and keep all your follow-up appointments; don't use any over-the-counter medications without first talking to your doctor. Cool compresses and elevating the affected part of your body may help relieve pain and swelling while your medications are doing their work.
In most cases lymphadenitis clears up quickly with proper treatment, but it may take more time for lymph node swelling to go away. Be sure to let your doctor know if your lymphadenitis symptoms come back.