Canker Sores: Causes & Remedies

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Ever noticed a small whitish, yellow ulcer in your mouth that was slightly tingly in sensation and healed by itself? You most likely suffered from an aphthous ulcer or a canker sore. A one-off canker sore is usually not a concern for most people.


But, when these canker sores are large, painful or take longer than usual to heal, they need your dentist’s attention. Canker sores are not the same as cold sores, do not occur on the lips, and are not infectious. So, what causes canker sores?

Identifying a Canker Sore

As mentioned earlier, canker sores are ulcers that occur inside the m outh. Most people who suffer from them do not know what they are or what causes canker sores. Canker sores are the most common type of oral lesions and affect around 20% of the world’s population. They are more likely to occur in women than in men and are also found to run in families.


They are usually small in size and are open ulcers that can make eating and other functions using your tongue painful. Before we understand what causes canker sores, it is important to know the types and how to identify them.


Canker sores can be of three types:

  • Minor Canker SoresAs the name goes, these are small in size(<1cm), appear in younger individuals between the age of 10-20 years and they appear and heal 3-4 times a year.
  • Major Canker SoresThese sores are rare, usually over 2cm in size and mostly painful to the individual. Though they heal without scarring, these canker scores bring them to their dentist.
  • Herpetiform Canker SoresThese are tiny sores that are rare and usually occur in older individuals. They occur in clusters, have irregular edges and heal within 1-2 weeks.

When Should You See Your Doctor?

Not all canker sores need you to seek dental treatment. When you learn more about what causes canker sores, you must avoid these causative or trigger factors. But, when do you see your doctor if you have canker sores?


As mentioned earlier, most of the canker sores heal by themselves without your dentist intervening. However, here are a few reasons it might be a good idea to visit your dentist if you have canker sore:-

  • Large, painful canker sores
  • Recurring canker sores or their frequent eruptions
  • Sores that last longer than 2 weeks
  • Extreme discomfort or pain while eating
  • Fever along with the eruption of canker sores

What Causes Canker Sores?

So, what causes canker sores? There are no causes that can be pointed out to be the exact causes of canker sores in the mouth. Studies show that they are caused due to a combination of factors and the causes are different for different people.

Here are some causes of canker sores –

  • Stress: Chronic and frequent stress, including emotional stress, is one of the most common causes of canker sores in the mouth. Stress triggers off a certain chemical reaction in the body and results in canker sores. So people who ask “what causes canker sores in me frequently?” must evaluate their stress levels and try to reduce them!
  • Hormonal changes in women: As we saw earlier, canker sores are more common in women. But, what causes canker sores in women more commonly than in men? Well, it is the hormonal changes that occur during menstruation. Many women see the appearance and disappearance of these canker sores during their monthly cycles.
  • Nutritional Deficiencies: Many people prone to nutritional deficiencies like vitamin B12, folic acid, iron, zinc, etc., because their diet lacks these nutrients. But, these nutritional deficiencies cause canker sores.
  • Trauma/InjuryTrauma-related canker sores are the most common ones that people suffer from. These canker sores occur due to sharp edges of teeth, trauma while using dental appliances, eating hard foods etc. The next time you get a canker sore after eating a hard food item, it might be your answer to “what causes canker sores?”
  • Drugs: Many drugs can lead to canker sores. Some of these include aspirin, beta-blockers, immunosuppressants, NSAIDs, sulfa drugs, vasodilators, antibiotics, antihypertensives, among many others.
  • Helicobacter pylori infectionHelicobacter pylori infections are notorious for causing peptic ulcers. But, they can also cause canker sores.
  • Toothpaste containing sodium lauryl sulphate: Allergic reactions to toothpaste, mouthwashes etc., that contain components such as sodium lauryl sulphate can result in canker sores in some people.
  • Sensitivity to certain foodsEating some foods like citrus fruits, or other acidic fruits and vegetables can cause canker sores. However, among the many reasons for getting canker sores, these are not usually detected easily.

How To Get Rid of Canker Sores?

Now that we know what causes canker sores, here’s how you can get rid of them!

  • The pain is usually bearable. But, if it is too much or causes a lot of discomfort, some medicated topical application gels are useful
  • Using medicated mouthwashes prescribed by your dentist can provide symptomatic relief and also help your canker sores heal
  • Oral medications may sometimes be prescribed to treat canker sores. These can include steroids, Carafate or colchicine
  • If your canker sores are a result of nutritional deficiencies, then loading up on the essential deficient nutrients is a good idea

Canker sores are easy to treat and even more easy to prevent. If you are prone to them, you might still be troubled by them often but there are ways to reduce their chances of return:-

  • Eat healthy nutritious food
  • Keep your hormones balanced
  • Avoid biting into large pieces of hard foods that can hurt soft tissues in your mouth
  • Use a soft-bristled brush

If you are prone to canker stores and are often troubled by the question “what causes canker sores?”, visit our team of dental experts at Sabka Dentist!


Expert opinion

    Dr. Zita Antao Dental Director of Sabka dentist says “Canker sores are small, open ulcers that are commonly seen inside the mouth.”

    Dr. Preethi Nagarajan Dental Director of Sabka dentist says “There are many reasons that cause canker stores.”

    Dr. Reena Waghela Dental Director of Sabka dentist says “They are different from cold sores and are non-contagious.”

    Dr. Ankita Gada Dental Director of Sabka dentist says “With the right treatment, your canker sores can be easily relieved.”

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One thought on “Canker Sores: Causes & Remedies

  • Aayushi

    I get ulcers every month and I don’t know why. Now I know the reason. Thanks for the blog

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