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What Causes a Swollen Mouth & When to Seek Care

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Last updated February 18, 2021

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Take a quiz to find out what's causing your swollen mouth.

Mouth swelling can happen in or around the mouth, such as the roof of the mouth, tongue, and lips. Causes range in severity, including temporary irritation from food or beverages to sudden swelling that may tighten the throat and restrict breathing. Read more below to learn about mouth swelling.

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Swollen mouth symptoms

The mouth is perhaps the most sensitive part of the body. If the mouth fails to detect you're eating something hazardous, this is potentially harmful. That's why your mouth responds right away with warning signals such as redness, pain, and swelling if it is touched by anything that might cause allergy or illness.

Common characteristics of a swollen mouth

If you're experiencing mouth swelling it can likely present with:

  • Swelling of the lips, tongue, and throat
  • Red, sore, blistered appearance on the inside of the mouth
  • A rounded lump anywhere inside the mouth: This lump may be painful or painless.
  • Difficulty speaking and with other mouth functions: Such as eating and swallowing due to dryness, pain, and swelling
  • Soreness and swelling of the roof of the mouth

Who is most often affected?

People who fit the following descriptions are more likely to experience a swollen mouth.

  • Anyone who smokes
  • Those not practicing good oral hygiene

Are swollen mouth symptoms serious?

The severity of mouth swelling depends on the cause.

  • Not serious: Temporary irritation from foods or beverages will heal quickly with a little care.
  • Moderately serious: See a physician for unexplained or persistent mouth swelling that causes pain or difficulty.
  • Serious: See a physician immediately for sudden swelling, throat tightening, and difficulty breathing.

What causes a swollen mouth?

Many conditions can cause the symptom of a swollen mouth. The following details may help you better understand your symptoms and when and if you need to see a physician.


Allergies will usually cause swelling in other parts of the body, too, as well as in the mouth, lips, tongue, and palate (the roof of the mouth). Allergies can be due to the following.

  • Foods
  • Medications
  • Products for your oral health
  • Skincare products or makeup
  • Plants that you have touched just before touching your mouth
  • Insect bites or stings on the lips or even the tongue

Traumatic causes

Traumatic causes of tooth swelling may include the following.

  • Dental treatment or surgery: These procedures may cause swelling right after.
  • Sports injury: A ball or another player may strike you in the mouth and result in swelling.
  • Another injury: A car accident can cause trauma to the mouth.

Infectious causes

Infections of the tissues of and around the mouth itself can result in swelling.

  • Bacterial infection: A bacterial infection can cause an abscess, which is a painful, infected lump inside the mouth.
  • Cold sores: A viral infection or "cold sore" can cause the roof of the mouth to swell at the same time the sore appears.
  • Spreading tooth infection: In rare cases, bacteria may spread from a tooth infection and get into the floor of the mouth. This infection can cause enough swelling to displace the tongue and push it back until it blocks the throat and, though rare, can cause difficulty breathing and a medical emergency.


Illnesses can lead to a swollen mouth, such as the following.

  • Viral illness: Some viral illnesses can cause swelling and itching of the roof of the mouth, along with a sore throat, swollen glands and tonsils, fatigue, and high fever.
  • Sinus infection: A sinus infection may cause swelling of the roof of the mouth as well as pain, pressure, fever, headache, and nasal congestion.
  • Blocked salivary gland: A blocked salivary gland can fill up with mucus and form a cyst. A cyst is a soft, painless swelling that will appear in the cheeks or on the floor of the mouth.


Redness, soreness, and swelling in the mouth can occur with repeated exposures to irritating substances such as the following.

  • Cigarette smoke
  • Chewing tobacco
  • Alcohol
  • Spicy foods
  • Rough, salty foods such as corn chips or jerky
  • Very hot beverages

Inflammatory causes

Inflammation of the mucosa, or tissues lining the mouth, can cause sores, redness, and swelling of the gums and mouth due to the following.

  • Radiation therapy to the head and neck
  • Chemotherapy
  • Oxygen therapy
  • Dehydration
  • Poor mouth hygiene
  • Alcohol and tobacco use
  • A very poor-quality, low-protein diet

Rare and unusual causes

More unusual causes of mouth swelling include the following.

  • Hereditary swelling: Some forms of swelling are hereditary and may involve the mouth and throat as well as other parts of the body (where the swelling is known as edema).
  • Tumors: These growths can cause swelling of the roof of the mouth if the tumor is above it or present as other types of mouth ulcers and lumps.

This list does not constitute medical advice and may not accurately represent what you have.

Oral herpes

Oral herpes infection or HSV-1 is caused by a virus called herpes simplex virus. It transmitted when a person with active sores has intimate or sexual contact, such as kissing or oral sex with another person. The first outbreak tends to be the most painful because people typically get a cluster of mouth sores and other symptoms such as fever, headache, sore throat, and swollen lymph nodes.

Rarity: Rare

Top Symptoms: fever, gum pain, painful mouth sore, gum swelling, gum redness

Symptoms that always occur with oral herpes: gum pain

Urgency: Self-treatment

Ludwig's angina

Ludwig angina is a bacterial infection of the floor of the mouth and occurs beneath the tongue.

You should visit an emergency room immediately. This requires immediate antibiotic treatment and, in some cases, surgery.


Gingivitis is the infection of the gums surrounding the teeth. It is caused by plaque and/or tartar that has built up on your teeth. Plaque is a sticky layer of gunk made by food particles, mucus, and bacteria. After a while, plaque hardens to become tartar (or calculus). Plaque and tartar at the bottom of the teeth causes the gums to become irritated and infected.

You should go to the nearest dentist in the next few weeks. There, the dentist or dental hygenist will clean your teeth, getting rid of that nasty plaque/tartar. Once cleaned, you should rinse your mouth twice-a-day with chlorhexidine 0.12% oral rinse (PerioGard) or half-strength hydrogen peroxide. Flossing and brushing your teeth are also essential.

Cold sore

A cold sore, also called a fever blister or herpes, is actually a collection of tiny, fluid-filled, crusted blisters.

Cold sores are caused by herpes simplex viruses HSV-1 and HSV-2. The sores are highly contagious through direct contact, such as kissing or oral sex, even when no sore is visible.

Most susceptible are young adults who are sexually active, though anyone can be infected. The virus can also survive on shared towels, eating utensils, etc.

Symptoms include a tingling or burning sensation around the lips, nose, or cheeks a day or so before the blisters appear. There may also be fever, sore throat, and other flu-like symptoms.

The herpes simplex virus cannot be cured, but cold sores can be managed under medical supervision to ease discomfort and help prevent transmission or complications.

Diagnosis is made through physical examination.

The blisters usually heal within two to four weeks, but the virus remains dormant within the body and can recur at any time. Antiviral creams or pills are sometimes used to help the healing process.

Canker sore

Canker sores are small, grayish-white sores in the mouth, often on the inside of the cheeks, lips, and on the tongue. No one really knows why canker sores happen, but it seems to be inherited and susceptible to vitamin deficiencies and allergies.

You can safely treat this condition on your own using Chlorhexidine mouth washes (Peridex or Periogard) or steroid medications (Orabase, Betnesol, or Ovar).


Angioedema is a condition which can cause swelling and puffiness of the face, mouth, tongue, hand or genitals. It is often related to an allergic reaction to food, medicines or insect bites.

Allergic reactions can be dangerous and therefore you should be brought to the nearest Emergency Room for evaluation and treatment. Call for an ambulance if you are experiencing any of the following symptoms: fainting, vomiting, trouble swallowing, tightness in throat or trouble breathing.

Rarity: Rare

Top Symptoms: nausea or vomiting, abdominal cramps (stomach cramps), diarrhea, swollen face, hand swelling

Urgency: Hospital emergency room


Anaphylaxis is the sudden onset of breathing or heart rate changes that are caused by a whole-body allergic reaction. This can be a deadly situation.

Call 911 immediately for an ambulance. If you have been prescribed an epinephrine pen, use it. Don't do this if you have never been prescribed one!

Allergic reaction (not life-threatening)

When the body encounters a harmful substance, it responds with inflammation and swelling that can be protective. In many individuals, the body responds this way to substances that are not normally harmful, like foods or pollen. This is the basis of allergic reaction, or Type 1 Hypersensitivity.

You should visit a physician right away to discuss the allergy and its severity, if you have not already been diagnosed. Your doctor may order an allergy screen to see what other substances produce the response. If you begin to feel tightness in the throat or difficulty breathing, get to an ER as soon as possible.

Rarity: Common

Top Symptoms: swollen face, swollen lips, lip numbness, hives, red swollen bumps or patches with a pale center, lip redness

Symptoms that never occur with allergic reaction (not life-threatening): shortness of breath, throat itching

Urgency: Primary care doctor

Acute salivary duct stone (sialolithiasis)

A salivary duct stone is the most common disorder of the salivary glands (where you make spit). They can range in size from tiny particles to stones that are several centimeters in length.

You can try treating this at home and going to the doctor if things don't work. You can stay well hydrated, apply warm compresses, and massage or "milk" the duct with the stone in it. Another tip would be to suck on lemon drops or other hard tart candy (called sialogogues, which promote salivary secretions) throughout the day. Pain is treated with NSAIDs like Ibuprofen. If things do not get better or you cannot find the stone, it's best to go to your doctor.

Swollen mouth treatments and relief

At-home treatments

You can try the following treatments at home.

  • Reduce or eliminate tobacco use: Take steps to stop smoking and to stop using any chewing tobacco products.
  • Cut down or discontinue drinking alcohol
  • Practice good oral hygiene: Floss regularly and brush your teeth and gums at least twice per day.
  • Protect your face: Use approved mouth guards and face masks when playing sports that require them.

When to see a doctor

You should consult your physician for any unexplained or troublesome lump or swelling, especially if you have pain, fever, or the feeling that the throat is constricted.

When it is an emergency

Seek immediate swollen mouth treatment in the emergency room or call 911 if you experience the following, which are symptoms of anaphylaxis, a severe allergic reaction that can be life-threatening.

  • You have a swollen mouth and face with difficulty breathing
  • Rapid heartbeat
  • A rash
  • A feeling of panic

Questions your doctor may ask about swollen mouth

  • What part of your mouth is swollen?
  • Do you have a rash?
  • Does your throat feel itchy or irritated?
  • Are your symptoms worse while eating?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

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The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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  1. Arava M, Pinto A, AAOM Web Writing Group. Oral hypersensitivity reactions. The American Academy of Oral Medicine. Updated December 31, 2007. AAOM Link
  2. Anaphylaxis. U.S. National Library of Medicine: MedlinePlus. Updated April 17, 2018. MedlinePlus Link
  3. Shweta, Prakash SK. Dental abscess: A microbiological review. Dent Res J (Isfahan). 2013;10(5):585-591. NCBI Link
  4. Hennessy BJ. Mouth sores and inflammation. Merck Manual Consumer Version. Updated September 2018. Merck Manual Consumer Version Link
  5. Oral cancer. Johns Hopkins Medicine. Hopkins Medicine Link