Canker Sores (Apthous Stomatitis)


Posted on: 09/07/2018


Most people have, at some time in their lives, developed canker sores or mouth ulcers. These are small, round, whitish or yellowish ulcers that occur in the soft tissues of the mouth such as the tongue, gums or the inside of the cheeks. These are harmless and often heal spontaneously although they can be painful and produce a tingling or burning sensation. They are not contagious or malignant but may need to be investigated if they persist for weeks at a time. Sometimes, such ulcers can be associated with HIV/AIDS or even cancer.


What Are Canker Sores?

CANKER SORESCanker sores, mouth ulcers or ‘aphthous ulcers’ are lesions or sores that occur in the soft tissues of the mouth.

This condition is referred to as ‘aphthous stomatitis’. Canker sores are identifiable by their typically round or ovoid shape consisting of a whitish or yellowish central area with a raised rim and a reddened ‘halo’.

More than one such ulcer can appear at a time and these are usually painful, causing discomfort while eating, speaking or brushing the teeth.

The outbreak generally remains confined to the mouth and does not spread. Mouth ulcers can occur in otherwise healthy individuals but some studies have shown that recurrent outbreaks can be an indication of more serious systemic disorders.


What Causes Them?

Canker sores or mouth ulcers often appear following some minor trauma to the soft tissues in the mouth. But they may also be a sign of other diseases. Some studies have linked mouth ulcers with changes in the oral microbiome.

  • Certain foods can trigger an outbreak of mouth ulcers and different individuals may be susceptible to different food triggers.
  • Wearing dental braces as this can scrape or cause minor cuts on the inner surfaces of the lips and cheeks.
  • Sharply biting the insides of the cheeks or the lips by accident. Injury can also be caused by vigorous brushing or dental treatment.
  • Heredity can also be a factor.
  • Hormonal shifts, for example during the menstrual cycle.
  • Nutritional deficiencies, in particular, deficiency of vitamin B-12, folic acid, zinc or iron.
  • Food allergies.
  • Using a toothpaste containing an ingredient known as sodium lauryl sulfate.
  • Frequently recurring outbreaks might point to systemic disorders such as Crohn’s disease or celiac disease.


What Do They Look and Feel Like?

CANKER SORES bacteriaApart from the ulcers themselves, the individual may otherwise be completely healthy. The typical signs of mouth ulcers are:

  • One or more clearly identifiable lesions or sores composed of a lighter colored central area rimmed by irritated tissue and a reddish halo.
  • Depending on the type, these may also manifest as groups of pinhead-sized individual sores.
  • A burning or sharply tingling sensation when exposed to salty, spicy or acidic foods. Rarely, these may be accompanied by – fever or swelling of the lymph nodes.


What Are The Different Types of Canker Sores?

There are four main types of canker sores or mouth ulcers.

  • Minor: These are the most common variety and typically appear as rounded or ovoid spots surrounded by a reddish boundary. These can occur individually or more than one at a time and are spontaneously resolved within a week or two. These ulcers usually range in size from an eighth to a quarter of an inch.
  • Major: These are generally larger than the minor variety and can be far more painful. These also take longer to heal, lasting up to six weeks at a time and leaving behind scars. Such ulcers can recur frequently. They can be irregularly shaped and can also appear at the back of the throat.
  • Herpetiform: Contrary to what the name suggests, there is no correlation with herpes. This type is not as common as the other two and usually appears in the form of numerous tiny pinhead-sized sores clustered together. These can be extremely painful. Although they usually heal within a week or two and do not cause any scarring, recurrence is usually so frequent that there may be no temporal gap between episodes. This type is found to occur more often in women than in men.
  • Recurrent Aphthous Stomatitis (RAS): This type is associated with an underlying medical condition such as celiac disease, inflammatory bowel disease, Behçet’s disease or Sweet’s syndrome. These can arise alongside similar lesions in other mucous membranes such as those in the genitals or the conjunctiva of the eye. RAS ulcers are sometimes referred to as ‘aphthous-like ulcers’ by sources that consider them to be distinct from the three types of aphthous stomatitis discussed above although there is no histopathological distinction.


Can There Be Any Complications?

In some cases, mouth ulcers are so painful that the patient is unable to eat. In extreme cases, this can lead to loss of weight and malnutrition. Unusually large sores, ones that persist for more than two weeks or reappear regularly should be shown to a doctor. The same goes for those that are accompanied by fever or lymph node swelling.


Diagnosing Canker Sores

CANKER SORES (APHTHOUS STOMATITIS)Mouth ulcers, especially those of the minor variety, are very common and most people experience them at least a few times in their lives. Therefore, most of us can easily identify one when it appears and may even have some sense of how long it might take to heal. We might also have identified patterns that trigger these sores.

For instance, some women find that at certain points in their menstrual cycles, they are more likely to develop mouth ulcers. Others may observe that these ulcers appear during periods of stress or anxiety. Yet others tend to attribute their ulcers to certain food triggers, disturbed digestion or medications.

In the event that the ulcer continues to cause pain for an abnormally long length of time, it might be necessary for a doctor to examine it. In some cases, the patient may have a family history of recurrent mouth ulcers or may, in fact, be suffering from a disease that also causes such repetitive ulceration in the mouth. To look into the latter possibility, blood tests and even a biopsy of the ulcerated tissue may be called for.


Treatment and prevention

Treatment is usually not necessary for canker sores. They heal on their own within 7-10 days. In major cases, medical attention may be needed.


  • Make sure that you do not consume any food that you are allergic or sensitive to, as canker sores could be caused due to allergies.
  • Make sure to follow proper oral hygiene. Brush your teeth twice a day, floss once a day and avoid using mouth rinses that contain sodium lauryl sulfate. Use a soft toothbrush to avoid irritation.
  • Reduce stress levels as the frequency and severity could cause canker sores.
  • Make sure to drink plenty of water.


  • Canker sores are also called aphthous ulcers or stomatitis.
  • In North America, 20-50% of the population has this condition.
  • They occur due to certain food intolerance, stress or trauma.


  • They appear on the cheeks, gums, lips, tongue, top or floor of the mouth.
  • The sores develop within 24-48 hours. They take up to 7-14 days to heal without scarring.


  • It is highest among people aged between 30-40 years in Japan, Southeast Asian, the Middle East and Southern Europe.


Dos and Don'ts

  • Apply ice or suck on an ice cube to relieve pain.
  • In case of braces, make sure that they fit properly so as to avoid any sharp edges that may irritate your mouth.
  • Brush teeth gently and regularly with a chemical-free toothpaste and a soft brush.
  • Consume rough foods such as chips, acidic beverages etc.
  • Chew inedible things.
  • Consume hot, hard or spicy foods as it can aggravate pain.




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