What Causes Canker Sores on the Tonsils?

Food allergies may cause canker sores on the tonsils.
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  • Written By: K. Gierok
  • Edited By: Lucy Oppenheimer
  • Last Modified Date: 26 November 2014
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Though most people think of canker sores as those sores that develop on the inside of the lip or cheek, they also can develop on the tonsils as well. When they develop on the inside of the cheeks, lips or gums, they're usually the result of biting or injuring the area; when they develop on the tonsils however, they usually were caused by allergies to something ingested like food, medication, or even oral hygiene products. Beside being an allergic reacting tonsil canker sores may result from poor oral hygiene.

Food allergies are one of the most common causes of canker sores on the tonsils. Foods that are often to blame for the development of this condition include strawberries, tomatoes, or other highly acidic fruits and vegetables. In addition, some types of shellfish are also linked to a high occurrence of canker sores on the tonsils. Individuals who develop these types of canker sores might benefit from keeping track of what they eat and when they develop the canker sore. This sort of tracking can help identify the cause of the sore so that that particular food can be avoided. Food allergy tests can also help uncover the particular food that causes the sores.


Allergies to certain types of medications can manifest as canker sores anywhere in the mouth, including the tonsils. Again, keeping track of what medications were introduced and when these canker sores developed will help identify which particular medication caused the sore. Sometimes, antibiotics may be the culprit. If a medication is the cause of the canker sore, it's important to consult a health care professional; ceasing the drug regimen without the advice of a professional can cause other problems.

Having canker sores on the tonsils has also been linked to toothpaste allergies. In most cases, the allergic reaction occurs due to a specific ingredient in the toothpaste. Individuals who experience an allergic reaction to toothpaste should read the ingredient list closely. Comparing the ingredient list of an allergy-causing toothpaste with one that has not produced a reaction can help identify the canker sore causing ingredient.

In some cases, canker sores on the tonsils can be result from poor hygiene. Failure to brush one's teeth on a regular basis, for example, has been identified as a possible cause of canker sores. Brushing on a regular basis, using the right type of toothbrush, and applying appropriate amounts of pressure are all important in ensuring adequate dental hygiene.


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Post 8

I found something called Canker Patch in the drugstore. It works wonderfully if the sore is on the inside of your lip or cheek. You put this patch on and it adheres to the sore and it has some medication on it and when you wake up it is almost healed sometimes it takes another day. You cannot put it on your tonsil, though. So I guess we just have to figure something else out for that. Also, I have been eating a lot of strawberries and my canker sores seem to be cyclical.

Post 6

Strawberries were on sale absurdly cheap at the supermarket, so I bought and ate an entire container on Monday and Tuesday. By Tuesday, I had a very bad sore throat and swollen glands that I assumed was from a developing cold. Yesterday, I was convinced that it must be strep, although I have not had a fever or any other symptoms of a cold or infection.

Today is Saturday morning and the canker sores on my tonsils are still there. I have also eaten shellfish over the past two days, so who knows if I've eaten more than one thing to cause it. I've had the same reaction to sodium lauryl sulfate -- many canker sores, and the constant brushing I was doing (thinking I didn't do a good enough job) was making it worse. No more toothpaste with that ingredient and I guess now, no more strawberries either.

Post 5

I get a canker sore on my tonsils every couple of months, but this is the first time I've heard of it being a food allergy, though. They feel like you have a sore throat, but are more of a piercing/burning than sore pain.

I am allergic to aspartame (a lot of people are, but don't know it), so chewing sugar-free gum causes a mouthful of canker sores for me and also sodium lauryl sulfate (SLS) found in toothpaste makes canker sores worse and lasts longer. I use Sensodyne toothpaste now, or Toms of Maine.

As for getting canker sores to go away faster, I've tried the oral canker sore mouthwashes. They work all right, but the best thing I've used is a gritty gel paste prescription from my doctor that "knits" your skin back together. I can't remember what it's called though. Highly recommend the gel, but it won't help with the ones on your tonsils.

To make you all feel better about having one or two canker sores at a time, I got a viral infection once and easily had over 100 canker sores cover my mouth, tonsils and throat. Couldn't eat or drink hardly anything for a week.

Post 4

Does anyone have any tips for some canker sore remedies that work? When I get a canker sore I usually just wait for it to go away, but would like to find something that would speed this along. Sometimes it can take weeks for a canker sore to go away and having one on the tonsils is not any fun.

This happened to me when I had a reaction to a new antibiotic I was prescribed. This is the only time I have had a reaction like this, and I stopped taking the medication right away.

Post 3

I guess someone can be allergic to just about everything, but I never thought about someone having toothpaste allergies. What would be an ingredient in toothpaste that would cause a canker sore on the tonsils?

I use a natural toothpaste that is sweetened with xylitol, but use this for health purposes and not because I am allergic to any certain kind of toothpaste. I have had a canker sore on the tongue which was more annoying than anything else. I imagine that canker sores on the tonsils would be a lot worse than any other place in your mouth.

Post 2

@LisaLou-- The exact same thing happened to my dad who had been eating fresh tomatoes for years. He found out he can eat the orange tomatoes and not have any problems because they don't have as much acid.

I have never had a canker sore on my tonsils but imagine they can be pretty painful. I have had them on the inside of my cheek before and I just chew on the opposite side of my mouth until the canker sore goes away.

If they were on your tonsils, there isn't any way you could avoid them if you wanted to eat or swallow anything.

Post 1

The first time I realized someone could get a canker sore on a tonsil was when this happened to my sister. She loves fresh tomatoes and plants a bunch of them in her garden every year. She uses these to make salsa, and she can also sit down and eat a whole plate full of them at one time.

After the tomatoes were in season for a few weeks, she developed canker sores on her tonsils because of the high acidic content of the tomatoes. Once she stopped eating them, the canker sores went away.

She was relieved that they went away, but really misses eating those fresh tomatoes. She can get by with eating a few slices, but not nearly as many as she used to eat at one time.

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