A swollen lymph node under the jaw can be caused by a tooth, most often an abscess, an infected wisdom tooth or inflamed gums, because the nodes beneath the jaw filter fluid draining from the teeth, gums and tongue. It is also commonly caused by a cold, sore throat or other minor infection. Most reactive lymph nodes typically settle within about 2 weeks once the cause clears. A node that persists, keeps growing or comes with other warning signs needs checking.
Key Takeaways
- The submandibular and submental lymph nodes under the jaw and chin drain the teeth, gums, tongue and floor of the mouth.
- Dental causes include a tooth abscess, pericoronitis around a wisdom tooth, gum infection, mouth ulcers and healing after an extraction.
- Non-dental causes include colds, flu, throat infections, salivary gland problems and skin infections on the face or scalp.
- A reactive node usually settles within about 2 weeks once the infection or irritation resolves.
- A node that is hard, fixed, painless and growing, or that lasts more than 2 to 3 weeks without a clear cause, should be checked by a GP or dentist.
- Spreading facial swelling, fever, or difficulty swallowing or breathing needs urgent care at an emergency department.
Why a Tooth Can Make a Lymph Node Swell
Lymph nodes are small filters along the lymphatic system. When bacteria or inflammation are present nearby, the immune cells inside a node multiply, and the node becomes enlarged and often tender. This is called a reactive node, and it is a sign the body is responding to something rather than a problem in itself.
Under the jaw sit the submandibular nodes, and under the chin sit the submental nodes. Between them they drain most of the teeth, the gums, the tongue, the lips and the floor of the mouth. That is why a problem tooth often shows up as a tender lump on the same side, just inside the lower border of the jaw.
Dental Causes of a Swollen Node Under the Jaw
Tooth abscess
An abscess forms when bacteria reach the nerve of a tooth through decay, a crack or old trauma, or when infection collects in the gum. Typical signs include a throbbing toothache, pain on biting, a pimple on the gum or a bad taste. The nearby node often swells as well.
Pericoronitis around a wisdom tooth
A partly erupted lower wisdom tooth can trap food and bacteria under a flap of gum. The gum becomes sore and swollen, it may be hard to open the mouth fully, and the node under the jaw on that side is commonly tender. Our article on pericoronitis covers this in more detail.
Gum infection
Active gum disease or a localised gum infection can be enough to make a node react, particularly when the gums are bleeding and inflamed.
Mouth ulcers and minor injuries
A large ulcer, a bitten cheek or a burn from hot food can cause a mild, temporary node reaction that settles as the area heals.
After an extraction or dental treatment
Some node swelling after a tooth is removed is a normal part of healing. Swelling that increases after the first few days, especially with worsening pain or a bad taste, should be reviewed.
Non-Dental Causes Worth Knowing
- Colds, flu and throat infections. These are the most common reasons for swollen nodes in the neck, often on both sides.
- Salivary gland problems. The submandibular salivary gland sits close to the nodes. A blocked duct, often from a small stone, can cause swelling that gets worse around meals, and infection of the gland is called sialadenitis.
- Skin infections. Infected pimples, cuts or insect bites on the face or scalp can make nearby nodes react.
- Other conditions. Less commonly, persistent node swelling can be linked to other infections or medical conditions, which is why a node that does not settle needs checking.
Lymph Node, Salivary Gland or Abscess: How They Differ
| Feature | Reactive lymph node | Salivary gland swelling | Dental abscess |
|---|---|---|---|
| Location | Small, round lump under the jaw or chin | Larger swelling under the jaw, deeper and more diffuse | Gum, face or jaw near the affected tooth |
| Feel | Tender, rubbery, moves under the fingers | Firm, may feel tight or full | Tender, may feel warm, sometimes a gum pimple |
| Pattern | Follows an infection, settles as it clears | Often worse when eating or thinking about food | Toothache, pain on biting, bad taste |
| Usual next step | Treat the cause, recheck if not settling in 2 to 3 weeks | GP or dentist assessment, hydration, sometimes imaging | Dental treatment to remove the source of infection |
These patterns overlap, and the table is a guide rather than a way to diagnose yourself. An examination is the only reliable way to tell them apart.
Red Flags: When to See Someone Promptly
A simple rule: if the node is tender and you have a sore tooth or gum, start with a dentist. If there is no obvious cause and it is not settling, start with your GP.
See a GP or dentist promptly if a node:
- feels hard, is fixed in place and is not tender
- keeps growing over time
- lasts more than 2 to 3 weeks without a clear cause
- comes with night sweats, unexplained weight loss or ongoing tiredness
- appears alongside a mouth ulcer or patch that has not healed within 2 to 3 weeks
These signs do not mean something serious is present, but they do need checking. A non-healing ulcer or lump in the mouth is one reason oral cancer screening is part of a routine dental examination.
Go to an emergency department if you have
- facial or neck swelling that is spreading quickly
- fever with a dental infection and feeling unwell
- difficulty swallowing, breathing or opening your mouth
- swelling that pushes up under the tongue or closes an eye
These can be signs of a spreading infection that needs urgent hospital care, as explained in our article on facial swelling from a spreading dental infection.
What the Dentist Checks
When patients I see mention a lump under the jaw, the examination usually covers:
- The node itself. Size, tenderness, how firm it is and whether it moves.
- The teeth on that side. Tapping, biting and cold tests to look for an inflamed or infected nerve.
- Gums and wisdom teeth. Pocketing, bleeding, pus or a swollen flap of gum.
- Soft tissues. The tongue, floor of the mouth, cheeks and salivary gland openings, looking for ulcers, stones or patches.
- X-rays. To find decay, an infection at the root tip or an impacted tooth that cannot be seen directly.
If a dental cause is found, treating it, often with a root canal, drainage, cleaning around a wisdom tooth or an extraction, usually allows the node to settle. Antibiotics are not always needed, and on their own they do not remove the source. They are mainly used when infection is spreading or you are unwell. If no dental cause is found, the team at Lumi Dental will suggest seeing your GP for further assessment.
Common Questions
Can a tooth infection cause a swollen lymph node?
Yes, a tooth infection is a common cause of a swollen lymph node under the jaw. The node usually sits on the same side as the infected tooth and settles once the infection is treated.
How long does a swollen lymph node from a tooth last?
A reactive node typically settles within about 2 weeks once the dental cause is treated. If it lasts more than 2 to 3 weeks after treatment, it should be reviewed.
Can a swollen lymph node cause a fever?
The node itself does not cause a fever, but the infection behind it can. A fever with dental swelling and feeling unwell should be assessed the same day.
Should I see a dentist or a GP for a lump under my jaw?
See a dentist if you also have a sore tooth, swollen gum or wisdom tooth pain. See a GP if there is no dental symptom, you have cold or throat symptoms, or the lump is not settling.
Is a painless swollen lymph node worse than a painful one?
A painless node is not automatically serious, but one that is hard, fixed and growing needs checking. Tender nodes are more often linked to infection, which is usually easier to explain.
Get a Lump Under the Jaw Checked in Melrose Park
If you have a tender node and a sore tooth or gum, the team at Lumi Dental in Melrose Park can examine the area, take x-rays where needed and explain the likely cause. For pain or swelling that needs attention soon, book with our emergency dentist in Melrose Park. For a routine check, see our general dentist and our current deals, with a written quote provided before any treatment.
