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Updated on December 30, 2022
8 min read

Mouth Sores

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Mouth sores are a common condition that many people experience at some point in their life. They affect your ability to do the following:

  • Eat
  • Drink
  • Practice dental hygiene
  • Talk

Mouth sores, including canker sores (also called aphthous ulcers), are typically harmless and last just a week or two.1 However, mouth sores should not be ignored as they may indicate oral cancer or a viral infection, such as herpes simplex virus (HSV).2

What Do Mouth Sores Look Like?

Aphthous ulcers are round or oval, with a white or yellow center and a red border. They may develop on any of your mouth's soft tissues, including your:

You may also have mouth sores and inflammation in your esophagus, the tube that connects your mouth to your stomach. A tingling or burning sensation may occur a day or two before the sores develop.

8 Types of Mouth Sores (With Pictures)

Here are the different types of mouth sores:

1. Canker Sores

Medical Images of Cold Sores

image 2
Image source: NHS

Canker sores, also called aphthous ulcers, develop within the oral cavity.3 They appear as small ulcers with a white, yellow, or gray center and a flat red border. 

Severe canker sores may sometimes have a large diameter and a raised edge.

A canker sore typically starts as a red lump or patch. Before additional symptoms emerge, it may cause a tingling or burning sensation. 

Canker sores are painful. Fortunately, most heal on their own within 7 to 10 days.

There is limited research on the exact cause of canker sores. However, scientists have linked the condition to genetics. Other triggers include:

  • Fatigue
  • Stress
  • Mouth tissue trauma
  • Certain foods (citrus and acidic)

2. Cold Sores

Medical Images of Cold Sores

image 1
Image source: NHS

Cold sores are painful, fluid-filled blisters that form in clusters (often called fever blisters). These sores typically appear on the border of the lips, called the vermilion border.

Herpes simplex virus (HSV) produces infectious cold sores. HSV is spread by contact. For example, it is possible to contract HSV by kissing someone with a cold sore. Some people can feel ill for up to a week. But the majority of people with herpes do not become ill.

Once infected with herpes, the virus remains dormant in the body. Unfortunately, the virus reactivates in some people, causing cold sores to develop on the lips or other areas regularly.4

Several factors, including wind, sun, fever, or stress, can trigger a ‘flare-up.’ Cold sores often heal within a week. 

3. Candidiasis

image 16
Image source: CDC

Candidiasis, also known as oral thrush or moniliasis, is a yeast infection.5 It causes creamy white and red spots on the mouth's surfaces. 

This condition may be painful. It can also cause foul breath and trouble eating and swallowing.

Candidiasis is most common in the very young, the elderly, and people with a weakened immune system (such as patients with diabetes or AIDS). It is also common among denture wearers. 

4. Leukoplakia

Medical Images of Leukoplakia

Image source: NHS

Leukoplakia is a condition in which a white or gray patch develops on the mouth’s interior. It is caused by abnormal cell growth in the mouth lining. It typically appears under the tongue or on the inside of your cheeks. 

Leukoplakia differs from other causes of white spots, such as thrush or lichen planus, in that it may progress to oral cancer.

Patches of leukoplakia appear gradually and heal over time.

Common causes of these mouth sores include:6 

  • Smoking or chewing tobacco
  • Certain foods
  • Cheek biting
  • Irregular dental restorations
  • Damaged teeth 

Sometimes, it is impossible to pinpoint the cause of the sores.

Leukoplakia is usually of no concern, although it does have the potential of becoming cancerous.

5. Erythroplakia

Medical Images of Erythroplakia

image 17
Image source: ScienceDirect

Erythroplakia is a red, velvety lesion that may appear anywhere in the mouth. It is most often found on the gum tissue behind the back teeth or the floor of the mouth.7

The cause is unclear, although it is most likely linked to smoking tobacco and alcohol consumption. Chronic inflammation and poor diet can also play a role. 

Erythroplakia is less common than leukoplakia. However, biopsies reveal that most of these sores are precancerous or malignant.

6. Oral Cancer

image 18
Image source: University of Utah

White or red lesions, lumps, or ulcers in the mouth may all be signs of mouth cancer. It often starts small and painless, but it rapidly grows and spreads. 

Most oral cancers are detected during routine medical checkups. The sores from oral cancer may appear on the lips, tongue, gum, or the roof of your mouth.

Contributing factors to oral cancer include smoking cigarettes, smokeless tobacco, and alcoholic beverages. According to experts, 90 percent of all oral cancer cases are due to the use of tobacco products.8

7. Celiac Disease

Medical Images of Erythroplakia

image 3
Image source: Beyond Celiac

Celiac disease is a digestive disorder that affects the small intestine. It occurs when gluten, a protein found in wheat and other grains, damages the lining of your small intestine.

This can cause inflammation and damage to the villi (finger-like projections) on the surface of the small intestine. The villi absorb nutrients from food as it passes through the intestines. 

Mouth sores are one of the most common symptoms of celiac disease. The symptoms can improve by adopting a gluten-free diet.

8. Hand, Foot, and Mouth Disease

image 19
Image source: CDC

Hand, foot, and mouth disease (HFMD) is a viral illness that's common under 5 years old. It usually starts with a fever and rashes on the hands and feet. HFMD can also affect the mouth and tongue, causing mouth sores.

The virus that causes HFMD spreads easily between people who come into close contact with each other. These viruses include:

  • Coxsackievirus A16
  • Coxsackievirus A6
  • Enterovirus 71 (EV-A71)

Mild symptoms of HFMD usually resolve within 7 to 10 days.

What Causes Mouth Sores?

You can develop mouth sores from viral, fungal, and bacterial infections or oral cancer.

Other risk factors include:

  • Irritation to the mouth tissues (for example, if dentures don't fit perfectly and cause friction with the mouth tissues)
  • Injury or trauma from external objects, such as orthodontic wires or sharp edges of broken tooth
  • Sensitivity to some ingredients found in toothpaste and mouthwashes
  • Medications or reactions to specific therapies, such as cancer treatment
  • Systemic disorders, such as oral lichen planus or inflammatory bowel disease
  • Tobacco use 
  • Exposure to irritants
  • Burns from hot foods or drinks
  • Acidic fruits
  • Spicy foods and drinks
  • Stress or lack of sleep
  • Tongue or cheek bites
  • Allergic response to certain foods or environmental elements
  • Nutritional deficiencies
  • Celiac disease

Other Symptoms of Mouth Sores

Mouth sores usually produce redness and pain, particularly while eating and drinking. They may also make the area surrounding the sore feel hot or tingly. 

It may be difficult to eat, drink, swallow, speak, or breathe, depending on the sores' size, intensity, and location. Blisters may also form on the sores.

Other symptoms associated with mouth sores, depending on the cause, may include:

  • Joint pains
  • Fever
  • Diarrhea
  • Painful blisters
  • A frequent outbreak of the sores
  • Swollen lymph nodes
  • Fatigue
  • Bleeding gums

How to Treat Mouth Sores

Most mouth ulcers will go away without treatment. However, if your mouth ulcers are frequent and painful, there are various things you can do to manage the condition. 

Either way, going to a healthcare provider or dentist will be the best decision to rule out any underlying issues.

Professional Mouth Sore Treatments

When you see your doctor for mouth sores, they may prescribe a pain reliever, anti-inflammatory medicine, or steroid gel. 

If your mouth sores are caused by a viral, bacterial, or fungal infection, your doctor may prescribe antivirals, antibiotics, or antifungals to treat the disease.

Some mouth sores may be treated with a low-powered laser, which provides instant pain relief and often prevents sores from recurring.

Chemically burning the sore with a tiny stick coated in silver nitrate may alleviate pain in a similar way, although it is not as effective as a laser.

Your doctor will order a biopsy for further examination if mouth cancer is suspected. If oral cancer is detected, he or she will prepare a treatment plan for you which may include surgery or chemotherapy.

Home Remedies for Mouth Sores

Here are some home treatments for mouth ulcers:

  • Gargle salt water and baking soda
  • Place milk of magnesia on the sores
  • Apply ice
  • Take over-the-counter medications if the sores are accompanied by pain
  • Use mouth rinses containing a steroid for pain management
  • Use topical pastes
  • Take nutritional supplements such as Vitamin B-6, B-12, folic acid, and zinc
  • Consider natural remedies such as myrrh, chamomile tea, and licorice root
  • Avoid acidic foods and drinks
  • Abstain from tobacco use
  • Avoid alcohol
  • Use a soft-bristled toothbrush
  • Use toothpaste without sodium lauryl sulfate (SLS)

When to See a Doctor

If your mouth sores occur frequently, you may not know when it's the right time to see a doctor. 

Seek immediate medical attention if you notice any of the following:

  • Non-painful sores in one or more areas of the mouth
  • Unusually large sores
  • Rapidly spreading sores
  • Sores that are taking too long to heal (longer than three weeks)
  • A fever accompanying the mouth sores
  • The mouth sores developed after starting a new medication
  • Bacterial infections
  • Extreme difficulty eating or drinking

How to Prevent Mouth Sores

Here are some tips for preventing mouth sores:

  • Practice good oral hygiene by brushing and flossing regularly
  • Avoid alcohol consumption
  • Use a toothbrush with soft bristles to prevent irritation 
  • See your dentist for regular dental checkups
  • Avoid spicy, salty, and acidic foods
  • Talk to your healthcare provider to find out if you have nutrient deficiencies that cause mouth sores


Mouth sores are usually harmless but can become serious if left untreated. Many factors, including poor oral hygiene, trauma, and certain diseases, can cause them. If your mouth sores don't disappear within a few weeks, seek professional help immediately.

Last updated on December 30, 2022
9 Sources Cited
Last updated on December 30, 2022
All NewMouth content is medically reviewed and fact-checked by a licensed dentist or orthodontist to ensure the information is factual, current, and relevant.

We have strict sourcing guidelines and only cite from current scientific research, such as scholarly articles, dentistry textbooks, government agencies, and medical journals. This also includes information provided by the American Dental Association (ADA), the American Association of Orthodontics (AAO), and the American Academy of Pediatrics (AAP).
  1. Canker sore.” Mayo Foundation for Medical Education and Research (MFMER).
  2. Herpes - oral.” National Institute of Health (NIH).
  3. Canker sore.” U.S National Library of Medicine (NLM).
  4. Wald A, Corey L. "Persistence in the population: epidemiology, transmission." Cambridge University Press, 2007.
  5. Fungal Diseases: Candidiasis.” Center for Disease Control and Prevention (CDC).
  6. “Leukoplakia.” Mayo Foundation for Medical Education and Research (MFMER).
  7. Bedi, R, Scully, C. "Manson's Tropical Infectious Diseases (Twenty-third Edition)." Elsevier Ltd, 2014.
  8. Tobacco and Cancer” Center for Disease Control and Prevention (CDC).
  9. Mohammed F, Fairozekhan, AT. "Oral Leukoplakia." StatPearls Publishing, 2022.
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