Mouth ulcers, also known as canker sores or aphthous ulcers, are small but painful lesions inside the mouth.
These lesions may make eating, drinking, and talking uncomfortable. They are not contagious and usually heal within a few days to a week.
Mouth ulcers may develop after an accidental injury to the soft tissue lining in the mouth. However, other mouth ulcers may appear naturally.
In addition, people with a known family history of canker sores are more susceptible to developing mouth ulcers.
Mouth ulcers are self-healing. If the sore increases in size and becomes more painful, you may need immediate medical attention. If an ulcer does not go away on its own, it might be a sign of mouth cancer.1
Mouth ulcers are mostly round or oval and can affect the mouth, lips, or cheeks.2 They can be white, yellow, grey, or red and may appear swollen.
A mouth ulcer may start as a single ulcer and stay in the same state until it goes away. However, they can multiply in the mouth, but most mouth ulcers are harmless.
Mouth ulcers can sometimes be confused with cold sores. Cold sores are small blisters that appear on the lips or around the mouth. They start with a tingling and burning sensation.
However, canker sores may not be painful until they are triggered by certain foods such as citrus or acidic fruits and vegetables.
Mouth ulcers are typically under 5mm wide, and some may join together to form one large one.
Some types of mouth ulcers appear on the soft tissues of the mouth, such as:
The exact cause of mouth ulcer sores is unknown, and it can differ from person to person. However, a single mouth ulcer can result from minor injuries to the mouth’s soft tissues.
Some causes of mouth injuries include:
Some mouth ulcers are triggered by something else, and are typically recurring.
These are some triggers that might cause mouth ulcers to keep coming back:
Mouth ulcers can also be a sign of other medical conditions, including:
Symptoms of mouth ulcers vary. However, the primary sign that indicates a mouth ulcer is a red or white sore in the mouth. The sore might become painful, especially when eating or drinking.
Canker sores may also lead to swelling of the skin around them, especially when they are on the lining of the cheeks.
In addition, since most foods and drinks can make mouth sores painful, loss of appetite is common.
Because mouth ulcers usually disappear within a short time, you might not experience the symptoms discussed above. However, the symptoms may worsen during times of stress, sickness, or severe exhaustion.
Sometimes, mouth ulcers will be accompanied by mild fever symptoms. If this happens, further medical assistance is necessary.
See a doctor or dentist if you experience any of the following:
A mouth ulcer is diagnosed through a simple visual exam. However, further tests may be needed if you have other worrisome symptoms.
If your oral health expert is unable to identify the origin of your mouth ulcers, or if the ulcers do not respond to standard treatments, you may need a biopsy of the ulcer and some surrounding tissue.
A biopsy is a process that involves the removal of a tissue sample for examination and diagnosis.
The cause of the mouth ulcer will significantly determine the type of treatment you need.
In some cases, it might be as easy as smoothening a sharp tooth. In other cases, your dentist may recommend advanced treatment.
Mouth ulcer treatments include:
Just like any other medication, mouth ulcer medications have side effects.
Common side effects may include:
Although it is uncommon, canker sore medications can also induce life-threatening allergic reactions.
Trouble breathing, hives, and swelling of the face or neck are all symptoms of allergic responses associated with these medications.
If you think you have an allergic reaction to your canker sore medication, you should immediately seek medical attention.
This is not an exhaustive list of side effects. The best way to learn more about the potential side effects of canker sore medications is to speak with your oral healthcare professional.
Here are some home remedies to help heal canker sores fast:4
Some mouth ulcers do not have a cure, and they tend to recur throughout a person’s life.
Luckily, there are a few things you can do to prevent mouth ulcers or reduce their recurrence.7 For example, consider improving your mouth hygiene as poor oral hygiene is a known cause of mouth infections.
Some types of prescription medications, such as antidepressants, can also cause mouth ulcers.8 If your prescribed medication is causing sores in your mouth, consult your doctor for other options.
Change your toothbrush or toothpaste if you notice that they are the triggers to your mouth ulcers.
For instance, if you are using a toothpaste containing sodium lauryl sulfate (SLS), you should change it to a better toothpaste. There is a denaturing effect of SLS on oral epithelium that is responsible for mouth ulcers.
Products that contain sodium fluoride and are approved by the American Dental Association (ADA) are the best options.9
Your toothbrush could also be too harsh on your mouth lining. Try using a soft bristle toothbrush to see if the sores subside.
“Signs and Symptoms of Oral Cavity and Oropharyngeal Cancer,” American Cancer Society
“Management of Aphthous Ulcers,”American Academy of Family Physicians, 1 July 2000
“Effects of oral rinsing with triclosan and sodium lauryl sulfate on dental plaque formation: a pilot study,” National Institute of Health (NIH)
“Mouth ulcers,” Department of Health, State Government of Victoria, Australia
“Canker sore,” Mayo Foundation for Medical Education and Research (MFMER)
“The Treatment of Chronic Recurrent Oral Aphthous Ulcers,” National Institute of Health (NIH), 3 October 2014
“Mouth ulcers,” Oral Health Foundation
“Ulceration of the oral mucosa induced by antidepressant medication: A case report,” National Center for Biotechnology Information (NCBI), 03 November 2009
“Should toothpastes foam? Sodium lauryl sulfate: A toothpaste detergent in focus,” National Institute of Health (NIH)