Be a canker sore specialist: What you should know

By Sandie Tran, Pharm.D.May 16, 2023

What are canker sores?

Canker sores, also known as recurrent aphthous stomatitis (RAS), are round or oval oral ulcers that have red and inflamed borders with yellowish-white centers. Canker sores are very common among different types of oral ulcers that affect more than half of the population according to the American Dental Association.

Canker sores are found inside the soft tissue linings of the mouth, on the inside of the upper or lower lip, on the tongue, and sometimes on the soft palate. If you ever had a canker sore, you know that the resulting pain can be excruciating and can lead to debilitating oral functionality and impaired food and fluid intake.

The 3 Types of Canker Sores

It is important to identify your type of canker sore and assess whether the healing time falls within the average range. In general, if your canker sore takes longer than two weeks to heal, it may be time to contact your physician.

Type	Characteristic
Minor Aphthous Stomatitis	The most common type of canker sore Present in more than 80% of all canker sore sufferers This tends to be smaller in size (< 1 cm) Shorter in duration (7-14 days)
Major Aphthous Stomatitis	A more severe form of canker sores Present in approximately 15% of canker sore patients Usually larger in size (> 1 cm) Takes longer to heal (up to 6 weeks)
Herpetiform Aphthous Stomatitis	The least common form but also the most severe form Present in about 5% of all canker sore sufferers These sores appear as a small group of small canker sores, and may come together to form a larger sore These sores usually heal in 14 days

The 3 Stages of Canker Sores

Although canker sores may seem like they show up overnight, they actually go through a series of stages. Knowing which stage you are in might help to determine effective strategies in dealing with them.

Stages	Characteristic
Stage 1	Stage 1 is 1-3 days Early stage where you begin to feel a burning or tingling sensation This may be the best stage to intervene
Stage 2	Stage 2 is 3-14 days A yellowish white center starts to form The pain becomes more intense This stage typically lasts about 7 days, but may last longer for major and herpetiform canker sores The ulcer becomes inflamed and raised Be careful when eating because it's easy to accidentally bite your canker sore and further delay the healing process
Stage 3	Stage 3 is 6-14 days Healing begins Most canker sores will not result in any scarring If you canker sore lasts longer than 14 days, seek medical help

Etiology of Canker Sores

Medicine has come a long way and many diseases have been studied and clearly explained on the nature of their causes. Canker sores are so complex that science has not been able to pinpoint the exact causes. It is most likely because it’s a multifactorial process, and a combination of these different processes trigger the appearance of those dreaded mouth sores. These factors have been associated with the development of canker sores, and may help you identify your own triggers.

Type	Explanation
Trauma to the mouth	People who have ill-fitting dentures Braces can scratch and initiate injury to your mouth and consequently lead to canker sores Eating sharp foods such as chips or nuts Sports injury
Hormonal fluctuations	Women tend to get more canker sores around the time of progesterone spikes in their menstrual cycles
Allergies/intolerance	You may be able to identify certain foods or medications that trigger your canker sore
Deficiency in micronutrients such as vit B-12, folic acid, zinc, iron, and lysine	It may be advisable to take these supplements to make sure you have adequate levels Some people have problems absorbing vitamin B-12 due to different conditions
Sensitivity to certain acidic fruits or drinks	Examples of highly acidic fruits include pineapple and strawberries Examples of highly acidic drinks include sodas and orange juice
Toothpastes that contain sodium lauryl sulfate	This is a foaming agent commonly found in toothpaste It is a skin irritant that can trigger the development of canker sores
Stress	A study found that psychological stress was an important trigger factor for the initiation of recurrent ulcers
Helicobacter pylori infection	H pylori infection can lead to canker sores due to their effect on the pH balance in your mouth H pylori bacteria can find their way to minor cuts in your mouth and trigger canker sore development
Crohn’s disease	Crohn’s disease can lead to redness, swelling, or sores anywhere in your digestive system, including your mouth
Celiac disease	A study found that canker sores improved in patients with celiac disease after 6 months of gluten-free diet
HIV/AIDS	Oral ulcers affect 70-90% of patients with HIV/AIDS
Behcet's disease	A rare multi-system inflammatory disorder The earliest symptom of Behçet’s syndrome is usually painful canker sores on the mucous membranes that line the mouth

Canker Sore Versus Cold Sore

Canker sores are often confused with cold sores because of their similar sounding names and the location they are found. However, they are completely different. It is important to distinguish these sores so that you can properly treat them. Generally, canker sores are found on the inside of the mouth in the soft tissue area whereas cold sores are found on the outer mouth.

Canker Sore*	Cold Sore*

Conclusion

If you are a frequent canker sore sufferer, the best approach is to find your own triggers or underlying reasons so you can prevent them. Usually, the best person who can investigate the cause(s) of your canker sores is yourself. It may be a good idea to keep a journal to track your habits, your diet, and your routines to help you figure out a pattern for their appearance. Through trial and error, you will become a specialist in the management of your canker sores.

Sandie's Signature
Sandie Tran, Pharm.D.

*These images are under Fair Use: Copyright disclaimer under Section 107 of the Copyright Act in 1976. Allowance is made for "Fair Use" for purposes of criticism, comment, news reporting, teaching, scholarship, and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. All rights and credit go directly to its rightful owners. No copyright infringement intended.

Tags: causes cold sore vs. canker sore symptoms

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