Swollen Jaw: Causes and When It's an Emergency

A swollen jaw usually means there’s an infection or injury nearby. Common causes include a tooth abscess, an infected wisdom tooth, swollen lymph nodes and salivary gland problems.

Most causes of a swollen jaw need to be treated by a dentist or doctor, not in an ER. However, if your jaw swells quickly or makes it hard to breathe or swallow, it’s an emergency.

If you’re having jaw pain without swelling, check out the causes of jaw pain on one side instead. For a swollen jaw, the 9 causes below are grouped by where you feel the swelling.

What Causes a Swollen Jaw on One Side?

Generally, the swelling will be on one side of your jaw, since it’s coming from one tooth, gland or group of lymph nodes.

• Next to a tooth or on the bone of your jaw: tooth abscess
• Behind your last bottom molar: infected or recently removed wisdom tooth
• Under your jaw: swollen lymph nodes or salivary gland
• In front of your ear: parotid gland (salivary gland; sometimes swollen from mumps)
• Low on the front of your neck: swollen thyroid
• Inside your bottom jaw, hard and painless: mandibular tori (benign bone growths)
• Large square jaw: enlargement of jaw muscles (clenching), not swelling
• Jaw swelling after trauma (fall or blow): bruise, break or dislocation

If one side of your face has been drooping for a long time rather than swelling, check out the causes of a lopsided smile.

Dental Causes of a Swollen Jaw

There are 3 dental causes of a swollen jaw: an infected tooth, an infected wisdom tooth or swelling from having a tooth removed.

1. Tooth Abscess

A tooth abscess is when pus builds up from a bacterial infection, at the end of a tooth root or in the gums next to the tooth.

Other symptoms of a tooth abscess:

• Pain (often throbbing and can move to ear/jaw/neck)
• Pain when biting on tooth
• Bad taste in mouth / pus leaking from bump on gum
• Fever & swollen glands in your neck

A tooth abscess will not go away on its own. A dentist will likely drain the pus and either clean under the gum, save the tooth with a root canal or extract it. If the abscess has spread or you have a fever or feel unwell, you may also need antibiotics.

2. Pericoronitis Around a Wisdom Tooth

Pericoronitis is when the flap of gum over a tooth that hasn’t erupted fully gets infected. It’s most commonly seen with lower wisdom teeth.

You’ll likely have pain and swelling at the back of your jaw, a bad taste and swollen glands. Many people also have trouble opening their mouth wide.

A dentist can clean under the gum flap and may prescribe antibiotics if the infection has spread. If the problem keeps coming back, you’ll likely need to have the wisdom tooth extracted.

3. Swelling After Tooth Removal

Swelling is a normal part of healing after having your wisdom teeth removed (or any other tooth). You’ll have the most swelling in the first few days, then it gradually goes down. Apply a cold compress to your cheek to help reduce the swelling.

It’s normal to eat soft foods while you heal, but call your dentist if:

• Your swelling gets worse after a few days
• You develop a fever or pus
• Your pain gets sharply worse after a few days (could be dry socket)

Other Causes of Jaw and Neck Swelling

Most of these causes are not dental related, so you’ll usually want to see your doctor.

4. Swollen Lymph Nodes

Lymph nodes are small glands that filter germs. Those under your jaw and in your neck swell with colds, mono, strep or tooth infections, then shrink.

See a doctor if a node has no clear cause, keeps growing or lasts two to four weeks. The same goes for one that feels hard, doesn’t move or comes with night sweats or weight loss.³

5. Tonsillitis and Strep Throat

Tonsillitis is usually viral and results in swollen tonsils, a sore throat and swollen lymph nodes under your jaw.

Strep throat is caused by bacteria and comes on suddenly with a sore throat, fever and red tonsils. Your doctor will likely do a strep test and prescribe antibiotics if needed.

6. Salivary Gland Problems

Your salivary glands are in front of your ears and under your jaw:

• Stone: A small salivary gland stone can block the flow of saliva, causing swelling that gets worse with meals.
• Infection (sialadenitis): The gland may become infected with a tender swelling. Sometimes pus will drain into the mouth, and you may have a fever.
• Mumps: This viral infection causes swelling in front of your ears.

7. Thyroid Nodules

Your thyroid gland is low in the front of your neck, below your jaw. Thyroid nodules are common. Most are not cancer, but you should see your doctor to check them with an exam, blood tests and an ultrasound.

8. Jaw Injury

A fall or blow to your face can bruise, break, or dislocate your jaw. Go to an emergency room right away if:

• Your teeth do not fit together anymore.
• You cannot open or close your mouth.
• Your lower lip or chin feel numb.

9. Oral Cancer

Swelling in your jaw can rarely be caused by oral cancer. About 1.2% of people are diagnosed with mouth or throat cancer in their lifetime.⁷

Warning signs include:

• A lump or thickening in your cheek or neck
• A sore in your mouth that doesn’t heal
• Problems chewing or moving your jaw

Can Jaw Swelling Cause Complications?

Yes, though rarely. Most swelling settles with treatment, but an untreated infection can spread:

• Ludwig’s angina: This infection often starts with an infected tooth root or an injury inside your mouth. The swelling spreads under your tongue and chin. It can lift your tongue and block your airway.
• Peritonsillar abscess: This is a pocket of pus next to one of your tonsils. It makes swallowing very painful.
• Sepsis: This is a life-threatening reaction to an infection that can damage your organs.

Learn the signs of a spreading tooth infection, and get emergency care if you have trouble breathing or swallowing.

How to Treat a Swollen Jaw

Treatment depends on what is causing your swelling. For example, if a tooth is infected you need to see a dentist. If you have strep throat, you need antibiotics.

To help reduce pain and swelling until you’re seen, you can:

• Put a cold pack (wrapped in a cloth) on your jaw.
• Take over-the-counter pain relievers as directed.
• Suck on sour candy and massage your salivary glands if you have a salivary stone.

Don’t try to pop or drain the swelling yourself or take leftover antibiotics. If you have an abscess, you need to see a dentist to get rid of the infection.

When to See a Dentist or Doctor

Most jaw swelling starts with a tooth, so see a dentist first for swelling near a tooth or after dental work.

See a doctor first for a neck lump, or for swelling under your jaw that comes with a sore throat.

Any lump, sore or swelling in your mouth that lasts more than two weeks needs a dental exam.⁸

Call 911 or Go to the ER

Swelling that affects your breathing or swallowing is an emergency.³ Call 911 right away if swelling comes with:

• Trouble breathing or speaking, or a muffled voice
• Trouble swallowing, or drooling
• Swelling under your tongue or chin that lifts your tongue
• Sudden swelling of your lips, tongue or throat, especially with hives

If you think you’re having a severe allergic reaction (anaphylaxis), use your epinephrine auto-injector right away if you carry one, even without hives. Then call 911 and wait for help, even if you start to feel better.

Go to the ER right away for:

• Swelling that spreads down your neck or up toward your eye
• A swollen or painful eye, vision changes or a lot of swelling inside your mouth
• Fast-growing swelling, confusion or feeling very ill
• Trouble opening your mouth along with facial swelling
• After an injury, a jaw that won’t close or teeth that no longer fit together

If one side of your face suddenly droops rather than swells, call 911 right away. A sudden droop is a sign of stroke.

Same-Day Care

See a dentist or doctor the same day for:

• Gum or tooth swelling with pus or throbbing pain
• Facial swelling that may be from a tooth infection, even without a toothache or fever
• Painful swelling around a wisdom tooth, or mild trouble opening your mouth without facial swelling
• Worsening swelling or a fever after dental surgery
• A painful, swollen salivary gland with a fever

With a fever and facial swelling, go to the ER if you can’t reach a dentist. Swelling with a fever but no clear dental cause needs medical care the same day.

Make an Appointment If You Notice

• A neck lump with no clear cause, or one that lasts two weeks without shrinking, grows, feels hard or doesn’t move
• Swelling under your jaw that flares at meals
• A lump low in the front of your neck
• Swelling that keeps coming back