How to recognise and treat Mouth Ulcers (getting rid of canker sores) | Doctor O’Donovan explains…
How to recognise and treat Mouth Ulcers (getting rid of canker sores) | Doctor O’Donovan explains…

Published on Nov 27, 2019 and last reviewed on Sep 02, 2022 – 5 min read


Canker sores or aphthous ulcers are common red and shallow ulcers seen in the oral mucosa. To know its causes, symptoms, triggers, diagnosis, and treatment, read the article.

Canker sores, otherwise called aphthous ulcers, are red, small, painful, and shallow lesions that appear on the mucous lining of the mouth and gums. Multiple such lesions in the mouth make eating and talking difficult and painful. Most of these lesions get better on their own in a couple of weeks. But, if you get these ulcers frequently and if they do not heal in time, then consult a dentist immediately.

It predominantly affects women, teenagers, and runs in families, and are not contagious. You should not confuse this with cold sores, which are blister-like lesions seen on the lips, the roof of the mouth, and sometimes on the gums and is caused by the herpes simplex virus.

The condition that causes multiple and recurrent episodes of oral ulcers in otherwise healthy individuals is called recurrent aphthous stomatitis (RAS). Such frequent episodes of oral ulcers can also be seen in systemic conditions like fever with adenitis or pharyngitis, Crohn’s disease, celiac disease, HIV or AIDS, and cyclic neutropenia.

img-source – the nemours foundation

The common characteristics of a canker sore are that it is round or oval, red in color with a white or yellow center. They commonly develop under the tongue, inside of your cheeks or lips, gums, and the roof of the mouth. Most of the time, the place feels tingly a day before the sore appears.

Depending on their shape and other features, there are many types of canker sores. The common ones include:

Minor canker sores – These are the most common type. They are –


Oval in shape.

Have a red edge.

Heal in a couple of weeks without a scar.

Major canker sores – These are less common. They are –

Larger in size and deeper.

Round with well-defined borders.

Extremely painful.

And take about 6 weeks to heal and leave a scar behind.

Herpetiform canker sores – These are uncommon, and should not be confused with herpetic lesions or cold sores, as these mouth ulcers are not caused by herpes virus infection. They are –

Pinpoint in size.

Occur in clusters of 10 to 100, which can merge and form a larger ulcer.

The edges are irregular.

Heal in 1 to 2 weeks without scarring.

Canker sores usually heal on its own in about one to two weeks. But in the following conditions, consult a doctor immediately:

If the sore is unusually large.

If new sores keep developing before the previous ones heal.

If you have excruciating pain.

If you have a high fever.

If the sores last for more than a couple of weeks.

If the sore extends to the corner of the mouth or lips.

Canker sores are believed to be caused by a combination of factors and triggers, but the exact cause is not known. Some of the common triggers include:

Mouth injury from brushing, sports, accident, and dental procedures.

Helicobacter pylori infection.

Lack of sleep.

Sodium lauryl sulfate present in mouthwashes and toothpaste.

The acidic content in food like oranges, strawberries, and pineapples.

Hormonal changes or imbalance.

Food items like chocolate and coffee.

Vitamin and mineral deficiencies like vitamin B12 deficiency or deficiency of zinc and iron.

Irritation caused by braces.


Or sometimes, mouth ulcers are a sign of some severe medical conditions like:

Celiac disease (gluten intolerance).


Autoimmune diseases.

Behcet’s disease (results in inflammation in the entire body).

There is no specific test to diagnose canker sores. Your dentist will be able to identify them with the help of a visual examination. In case the sore is not healing or you get such sores frequently, then the dentist might ask you to perform some tests to rule out the conditions that can cause similar symptoms.

Minor cancer sores do not need any treatment, as they usually clear out on their own in a week or so. Treatment might be needed for larger and more painful sores. The treatment options include:

1) Mouthwashes – To reduce severe pain and inflammation, mouthwashes containing Dexamethasone or lidocaine are prescribed.

2) Topical creams or gels – To relieve pain and speed the healing process, your dentist might give topical gel or cream to apply on the sore. These ointments usually contain Benzocaine, Fluocinonide, or Hydrogen peroxide.

3) Oral medicines – If the sore does not respond to topical creams, then oral medicines are prescribed. Oral steroids are very rarely prescribed and used only when all other treatment options have failed.

4) Cautery – Here, an electrical instrument or a chemical is used to burn the ulcer. The chemicals used are Debacterol and Silver nitrate.

5) Nutritional supplements – To treat deficiency of folic acid, vitamin B12, iron, or zinc.

If the ulcers are due to an underlying health condition, then the underlying condition has to be treated.

Rinsing the mouth with saltwater or 1 teaspoon of baking soda in half a cup of lukewarm water.

Avoid acidic or spicy foods.

Eat ice chips.

Brush your teeth gently.

Drink warm chamomile tea.

Avoid overly spicy or food that can tear or irritate your oral mucosa.

Eat healthily.

Brush using a soft bristle brush.

Cover the sharp edges of braces with orthodontic waxes.

Manage stress.

For more information on oral lesions, consult a dentist online now!

The various causes for canker sores are:
– Viral infection.
– Menstrual cycle.
– Stress.
– Food allergy.
– Hormonal fluctuations.
– Vitamin deficiency.

A major canker sore has the following characteristics:
– The size of the canker is approximately 0.8 centimeter to 1.5 centimeters.
– The lesion stays in the body for more than two weeks.
– The margins of the lesion are very irregular.
– Formation of the scar is seen.

Applying salt on the canker sores is a good old method of curing the condition. Salt inhibits the growth of bacteria and reduces the size of the lesion. A very positive response can be seen in the first 24 hours itself. Using saltwater for gargling is also the best method.

Mouthwashes are not specifically designed to treat canker sores. The main goal of mouthwash is to maintain a healthy oral environment. However, the usage of mouthwashes are known to be beneficial to a certain extent as it can reduce the microbial load to a greater extent. Continuous usage of mouthwashes eventually reduced pain in many patients.

A canker sore is usually an injury or cuts on the surface of the oral mucosa or tongue. Our oral cavity is rich in digestive juices and acids. When this injury or the cut gets exposed to various digestive juices, the patients experience pain in the involved site.

If the canker sores do not heal even after the treatment options, then it might be due to the following reasons.
– Deficiency of folic acid, vitamin B-12, zinc, and iron.
– Gastrointestinal tract disease.
– Celiac disease.
– Crohn’s disease.

Any mouthwash that is free from alcohol is the most recommended one. This will lessen the gingival irritation and promote the healing of canker sores. In addition to the usage of mouthwash, the patient should go for topical or oral medications.

You can get rid of canker sores faster with the help of the following.
– Alum powder.
– Saltwater rinse.
– Baking soda rinse.
– Yogurt.
– Honey.
– Coconut oil.
– Hydrogen peroxide.
– Milk of magnesia.

Autoimmune disease like Behcet’s disease causes canker sores. Initially, it is seen as a round lesion, and in the later stages, it turns into a painful lesion. The progression of the ulcer into a complicated state happens rapidly.

Yes, vitamins can help in preventing canker sores. Vitamin B12 plays a vital role in maintaining the integrity of the oral cavity. A daily dosage of vitamin B supplements will help in overcoming recurrent conditions of canker sores.

Vitamin and mineral deficiencies are responsible for canker sores in some patients. The deficiency of folic acid, iron, zinc, and vitamin B12 is the reason for canker sores.

Viral organisms might be responsible for canker sores. The most common sores in the oral cavity are caused by the herpes simplex virus. Though it is a viral condition, it is mostly not contagious.

The following foods help in healing canker sores.
– Bland foods like cream soup and yogurt.
– Eat soft food items.
– Break your food into small parts.
You can avoid chocolate, coffee, citrus fruits, spicy foods, seeds, nuts, and tomatoes.

You can follow the below tips to overcome the condition of canker sores at home.
– Try gargling with saltwater.
– You can also gargle using half a teaspoon of baking soda mixed with water.
– Application of milk of magnesia on the canker sores can help in healing.

The canker sores might cause pain in the affected individuals for more than a week. If the canker sore is mild, then it usually heals within seven or eight days. A severe case of canker sore might take more than six weeks to heal.

Immediate medical care is necessary only if you experience the following symptoms.
– Difficulty in drinking and eating.
– High-grade fever.
– Canker sores tend to extend beyond the border of the lips.
– Increased recurrence of the canker sores.

Last reviewed at:
02 Sep 2022 – 5 min read


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