What is it?
Lymph nodes are small immune stations that filter the fluid draining from your tissues. There are hundreds of them in the head and neck; the ones under the jaw and in the upper neck drain the area served by your teeth, gums, tongue and tonsils. When inflammation starts in that area the node grows and becomes tender. This is called reactive lymph node swelling.
A reactive gland is usually soft or moderately firm, shifts when you push it with a finger, hurts when touched and most of the time stays under two centimetres across. It appears within a few days of the source starting. The source may be decay that has reached the nerve of a tooth, an abscess at a root tip, inflammation around a partly erupted wisdom tooth, advanced gum disease or an upper respiratory infection.
The gland itself is not the illness, it is the response. Once the source is treated the gland shrinks, but that shrinking takes weeks rather than days, and a small remnant can still be felt for months. A gland that keeps growing, becomes hard, sticks to the surrounding tissue instead of moving and causes no pain calls for a different assessment.
Signs
You will not necessarily have all of these at once.
Why does it happen?
- 01
Infections from the teeth and gums
Decay reaching the nerve of a tooth, an abscess forming at a root tip or advanced gum disease can all make the glands under the jaw that drain that area swell. The gland is most often on the same side as the tooth involved.
- 02
Inflammation around a wisdom tooth
Bacteria collect under the flap of gum lying over a partly erupted wisdom tooth. This repeated inflammation is one of the common reasons for a one-sided gland under the jaw and a one-sided sore throat.
- 03
Throat and upper respiratory infections
Tonsillitis, pharyngitis and viral infections often make the glands in the neck swell. Here the swelling is usually on both sides, comes with a high temperature and a sore throat, and settles as the infection clears.
- 04
Mouth ulcers and skin infections
Surface problems such as a mouth ulcer, a sore spot under a denture, a cold sore on the lip or an infected hair follicle on the face can also stir up the glands in the same area. As the source settles, so does the gland.
How does it progress?
- 1
The reaction
In the days after the source infection begins, the gland grows, hurts when touched and the skin over it looks normal. At this stage what actually produces the symptoms is usually not the gland but the source.
- 2
Treating the source
Once the tooth or gum treatment has been carried out, the gland stops growing. The tenderness usually eases within a few days; the size of the gland does not change at the same pace.
- 3
Settling down
The gland usually shrinks within two to six weeks. A small, mobile remnant that you can still feel may stay longer, and on its own that does not mean the treatment has come to nothing.
- 4
A gland that does not settle
A gland that has not shrunk after three or four weeks, keeps growing, becomes hard or sticks to the surrounding tissue is no longer regarded as reactive. At that point the assessment moves outside dentistry.
How is it treated?
Treatment is aimed at the source, not at the gland itself. A swollen lymph node is not drained or removed. What the dentist does is look for the source: an examination and X-rays are used to assess decay, infection at a root tip, gum disease or inflammation around a wisdom tooth. If a source is found, root canal treatment, extraction, drainage of a collection of pus or gum treatment comes onto the agenda.
Not every swollen gland needs an antibiotic. That decision goes by the type of source and the overall picture rather than by the size of the gland; an antibiotic given without dealing with the source most often eases the symptoms only for a while. Writing down how big the gland was on the day it was first seen, and which side it was on, is what gives you the real information at the next check-up.
If no explanatory source can be found in the mouth or on the X-rays, or if the gland is not settling within the expected time, the dentist's role ends there. From that point on it belongs with an ear, nose and throat specialist or a doctor in general medicine; blood tests, an ultrasound scan and, where needed, sampling are decided by that doctor. What the dental clinic contributes is assessing and ruling out causes coming from the mouth, and passing on the findings in writing.
- If the gland grows quickly over a few days and the skin over it turns red and feels hot
- If the floor of your mouth is hardening, or swallowing or breathing is becoming difficult
- If a high temperature, shivering and feeling generally unwell have been added
- If a gland has lasted more than three weeks, is becoming hard, does not shift and causes no pain
How is it prevented?
- Have decay and bleeding gums treated without waiting for pain to appear.
- If the area around a partly erupted wisdom tooth swells again and again, do not put off having it assessed.
- Finish the root canal treatment you left halfway because the pain had stopped.
- Note the date you first noticed the gland and which side it is on; that is the information that helps most at the check-up.
Frequently asked questions
- Will a swollen gland go away on its own?
- If the source is a passing infection it usually shrinks over a few weeks. If the source is on the tooth or gum side and is left untreated, the gland can be expected to stay where it is. So the answer depends not on the gland itself but on what the source turns out to be.
- Is a painless gland more serious than a painful one?
- Pain on its own does not sort the picture into good or bad. That said, glands that appear quickly, hurt and shift under the finger are most often a response to inflammation. A painless gland that has been there a long time, has become hard and is stuck to the surrounding tissue calls for a separate assessment, and that assessment is not within dentistry.
- Shouldn't an ultrasound scan or a blood test be requested?
- That decision is not the dentist's to make. When an explanatory source is found in the mouth and the gland settles within the expected time, further tests are most often not needed. If no source can be found, or the gland is not settling, the decision to request them is left to the relevant doctor.
This content is for general information and does not replace an in-person examination. Symptoms overlap between conditions, and a diagnosis can only be made clinically.