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Canker Sore on Tonsil? Here's How To Deal

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Medically Reviewed By Colgate Global Scientific Communications

You may already be familiar with canker sores, the non-contagious but sometimes unpleasant red and white ulcers that appear inside your mouth. Some people get them more than others, and they can range from a mild sore that lasts a couple of days to a more painful lesion that lasts a few weeks. Whatever your familiarity is with canker sores, you may not be aware that they can also develop on your tonsils.

If you feel like you have a sore throat but aren't exhibiting other symptoms of a common cold or sickness, you could be experiencing a canker sore at the back of your throat. Canker sores can affect any part of the mouth, including the gums, teeth, and yes, even your tonsils! The good news is this canker sore likely won't merit a trip to your medical or dental professional, but the bad news is that pain caused by a canker sore on your tonsil can disrupt your daily activities. To feel confident you're doing everything you can to mitigate your canker sore pain and reduce your chances of getting one again, let's go over everything you'll want to know about these pesky oral ulcers.

What Causes Canker Sores?

Unfortunately, the exact cause of canker sores is unknown. But we understand many of their triggers, including injury to the mouth (think of biting down on the inside of your cheek), food sensitivities, a vitamin B-12 deficiency, stress, and hormonal changes. Pain from an ulcer on your tonsil is probably caused by something you ate or drank. Food allergies and highly acidic foods can cause canker sores to form in this region of your oral cavity, as your tonsils come in contact with these irritants when you swallow.

Canker sores on your tonsils can feel very similar to a sore throat. Your tonsils may feel swollen, and you may attribute the pain to a run-of-the-mill cold, virus, tonsillitis, or strep. The best way to confirm that you have a canker sore on your tonsil is to use a mirror to look in your mouth and examine your tonsils. Generalized swelling or white spots on both tonsils signify an illness, but one large white round or oval sore with red edges on just one tonsil is most likely a canker sore.

How to Deal with Pain and Discomfort

There are plenty of ways to ease the discomfort of a canker sore on your tonsil, and you probably have the ingredients for a remedy right in your own home! One of the most common treatments is a saltwater rinse, which helps cleanse bacteria from the sore. A baking soda rinse, mixing one teaspoon of baking soda with a half cup of warm water can also help with the pain. Gargle and spit it out in the sink, making sure the rinse comes in contact with the canker sore. You can also try some of these at-home remedies:

  • Take over-the-counter medication such as ibuprofen or acetaminophen.
  • Try topical medications like mouth sprays containing benzocaine or phenol or an antimicrobial mouthrinse.
  • Eat cold or warm (not hot) and soft foods that are easy to swallow. Frozen yogurt, warm tea, and soup can be soothing to your throat and easy to get down.
  • Avoid eating foods that are acidic or spicy, which can exacerbate the pain of your canker sore.
  • Avoid any known irritants and if you tend to develop canker sores, pay attention to the foods that seem to be triggering them, such as sour candies or acidic fruits.

When to See a Dental or Medical Professional

A minor canker sore in your throat should start to diminish in pain after a few days and disappear within a week. But significant canker sores can take up to four weeks to disappear and may leave a scar once they've healed.

You should see a dental or medical professional about your canker sore for the following reasons:

  • Your canker sore lasts more than two weeks.
  • It's abnormally large.
  • It extends to your lips.
  • A high fever accompanies it.
  • You're unable to eat or drink because of how painful the sore is.

Canker sores on your tonsils are definitely unwelcome, but the good news is that they don't last forever! You may assume that your painful sore throat is a symptom of a more significant illness that will warrant a more extended recovery period. But a cold sore should have a relatively quick recovery time and only require at-home remedies for pain reduction. If you've just developed a canker sore, we know you're probably already itching to get back to the foods and drinks you love! But by giving your throat time to rest with mouthrinses and soft foods, you should be feeling better within a week!


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This article is intended to promote understanding of and knowledge about general oral health topics. It is not intended to be a substitute for professional advice, diagnosis or treatment. Always seek the advice of your dentist or other qualified healthcare provider with any questions you may have regarding a medical condition or treatment.

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