What are lymph nodes?
If you have ever touched the sides of your throat, you will have felt two harder little lumps just under the jawbones. These are the most commonly felt lymph nodes, but there are over 500 lymph nodes in your body, set apart diffusely. They can be found in the armpits, the throat, the stomach, and near the genitalia. Their function is to produce lymphocytes, which are the first line of defence that your body has against bacterial and viral infections. They basically act as filters that filtrate your blood and pump them full of antibodies and phages that attack foreign bodies and unwanted microbes that may be coursing through your blood.
Swelling or infection?
Because of the function of lymph nodes, they tend to swell when they are working, which can be very scary, but is quite normal. If there is even a very slight infection in your body, your lymph nodes will swell up and start to produce antibodies and lymphocytes. This swelling should go down very soon, and should not be sore or tender. Most instances of lymph node swelling go away on their own very soon, and last for just a few hours or days. If your lymph nodes are tender and you have some kind of pain or discharge around them, then we are dealing with an all-out infection, and this can be troublesome. Lymphadenitis is the official term for the inflammation of the lymph nodes, and it indicates that the body is fighting off an infection, either locally or somewhere else in the body. Many very scary diseases, like leukaemia, AIDS and various cancers are characterised in their early stages as just a chronic swelling of the lymph nodes, but more often than not some very mild bacterial, viral or fungal infection is at the heart of the swelling. It is of vital importance that you go to a doctor if your lymph nodes are swollen, just to be safe.
Since bacteria are abundant in your mouth, it should be no surprise that many causes of lymphadenitis are oral. Periodontitis and infections in your gums and other soft tissues almost always trigger both of the lymph nodes in your neck to become swollen and quite palpable. When the doctor checks the gums and they look like they might be infected, one of the first things they do is to palpate your lymph nodes; if these too, are swollen, then the chances of periodontitis are almost 100%. Teeth that need to be root canaled will also cause the lymph node on the side of the tooth in question to become swollen.
What to do
If your lymph nodes are swollen and you have or have had periodontitis, or have a tooth that needs to be root canaled or was root canaled in the past, it is well worth taking a trip to the dentist to get the situation checked out. If the cause of the swelling is from your teeth than the situation is not very serious, but as these infections strain your immune system, they are an unnecessary expenditure and should be dealt with in order to return to normal health.