There are many different types of mouth sores than can develop around or in the mouth. Some are painful, some are unsightly, and some may be a sign of something more serious. If your mouth sore does not go away within 10 days, you should consult your dentist. If you suspect you have an infection, consult your dentist as soon as possible to eliminate complications.

Signs & Symptoms


Burning Mouth
Burning mouth syndrome is a painful burning sensation that occurs in the mouth, tongue, palate, gums, inside of cheeks and throat areas. It can persist for months or years.

Known as “thrush,” it is a fungal infection that occurs in the mouth or throat due to an overgrowth of yeast. Symptoms include: white spots inside the mouth or on the tongue, sore throat, difficulty swallowing, and cracking at the corners of the mouth (cheilosis).

Canker Sores
Canker sores often develop as small white or yellow center lesions with a red border. They develop in the mouth on the tongue, inside cheek areas, lips, gum line and throat area. They are not contagious. Canker sores may occur as one sore or several.

Cold sores
Cold sores, also called “fever blisters,” appear as clusters of red, raised blisters outside the mouth—typically around the lips — although they can develop under the nose or under the chin. They are highly contagious and can break open, which allows the fluid in the blisters to leak out and spread the infection. They typically scab over until they heal.

Leukoplakia is a white or gray area that develops on the tongue, inside of the cheek or on the floor of the mouth. Leukoplakia is typically not painful or contagious.

This is a bacterial infection that occurs when there is an interruption of salvia flow from the salivary gland to the mouth. The gland is firm and can be painful with swelling of the area. If the infection spreads, one may experience fever, chills and malaise.

Tooth Abscess
A tooth abscess occurs when there is a bacterial infection in the nerve of the tooth. Symptoms of a tooth abscess include severe toothache with pain, sensitivity to hot and cold beverages or food, fever, and swollen lymph nodes.



Burning Mouth
The cause is not clearly understood. Some common causes may be: nutritional deficiencies, dry mouth, oral thrush, diabetes, hormonal changes, certain medications, and anxiety or depression.

Thrush is caused by a fungus and typically develops when the immune system is weakened. Some medications, such as steroid or cancer therapies, may increase the risk of developing this infection. Antibiotics also increase the risk of developing infection because they can alter the normal balance of bacteria in the mouth.

Canker sore
In some cases, the exact cause of a canker sore is unknown, but trauma or injury to the mouth or oral soft tissues may be the culprit. Other possible causes are food sensitivities, spicy, salty or acidic foods, vitamin B deficiency, hormonal shifts and stress.

Cold sore
Cold sores are caused by the herpes simplex virus (HSV)-1 and are highly contagious. The initial infection with the virus can be accompanied by cold or flu-like symptoms and can cause painful oral lesions. There is no cure for the herpes virus. Reoccurrence can occur when an individual has a fever, menstruation, fatigue, stress or exposure to the sun.

These can result from irritations that occur from fillings, crowns or ill-fitting dentures. Other causes include tobacco use, HIV/AIDS and the Epstein-Barr virus. Sometimes, leukoplakia is associated with oral cancer, so it’s important to see your dentist, if you notice any of these patches developing. Your dentist may recommend a biopsy if the patch appears suspicious.

Sialadenitis a bacterial infection of a salivary gland and can be acute, chronic or recurrent. Pus may drain through the salivary gland into the mouth. These infections occur most often in the parotid gland.

Tooth Abscess
A tooth abscess occurs when bacteria invade the dental pulp, the nerve and blood vessels of the tooth. Bacteria enters the pulp and spreads to the root. The bacterial infection causes pain, bad breath and inflammation. The tight space, within which the inflammation occurs, forces pus into a pocket (abscess) at the tip of the root.


You dentist will carefully examine the inside of your mouth, tongue and glands. Although many of these sores and infections may be harmless, some are not, so it is important to talk to your dentist about the problems you are experiencing and feeling in your mouth.


Regular checkups will increase the likelihood that suspicious sores and infections in your mouth are found early. In between visits, get to know the signs, and what to do, if you find anything suspicious.


Burning Mouth Medications can be prescribed to alleviate underlying causes of burning mouth syndrome. You can take certain actions to reduce your symptoms by avoiding alcoholic beverages, tobacco use, acidic and spicy foods and beverages, and stress.

Candidiasis Thrush is treated with a prescription antifungal medication. It is most commonly seen in HIV/AIDS patients, after cancer therapy, organ transplant, diabetes and in denture-wearers.

Canker sores These usually heal without treatment one or two weeks after they break out. However, if they are painful, over-the-counter topical anesthetics and antimicrobial mouth rinses may provide temporary relief.


Leukoplakia Treatment begins with identifying the source of the irritation. Once the irritant is removed, which may mean smoothing a rough tooth surface, repairing a dental appliance or quitting tobacco use, the patches should disappear.

Sialadenitis Hydrating is the first step in treatment. Next, antibiotics are given to destroy the bacteria. If the infection does not improve, surgery may be needed to open and drain the salivary gland.

Tooth abscess A root canal can eliminate the infection and save the tooth. If the tooth cannot be saved, a dentist will extract the tooth and drain the abscess to eliminate the infection. An antibiotic will be prescribed to stop the bacterial infection.

Related Conditions

While most sores and infections can be treated and/or managed effectively, some are more serious and in rare instances could be a sign of oral cancer. Be on the lookout for a white or reddish patch inside the mouth, as well as a lump or thickening of the skin or mouth lining. Other symptoms include tongue pain, loose teeth, jaw pain, difficulty in chewing or swallowing, or even just a sore throat. Oral cancer can occur anywhere in the mouth, including the gums, lips, tongue, roof of the mouth, floor of the mouth and inside lining of the cheeks and the throat.

Other Info About Mouth Sores and Infections

Mouth sores got you feeling blue?


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    Colgate® Peroxyl® Mouth Sore Rinse is a patented oral debriding agent/wound cleanser for temporary use to cleanse canker sores and minor oral wounds or minor gum inflammation.