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Health Information | 03/16/2017

Canker Sores

By  Nathan Samuels, DNP, MSN, ANP-BC

What is a Canker Sore?

A canker sore is the common term for an aphthous ulcer, a lesion inside the mouth that looks like a shallow, round, white, or gray spot, often with some redness around the edge. When there are multiple ulcers, we call them “aphthae.” These lesions are painful and can make it uncomfortable to eat, drink or chew. Canker sores are not contagious, they usually last up to 2 weeks, and heal on their own.

What Causes Canker Sores?

The cause of canker sores is not fully understood. We do know the cells of the mouth seem to have an over-reactive immune response, and several internal as well as environmental factors can cause a canker sore or sores to develop:
  • A family history of cankers, trauma (e.g. biting the lip/cheek or dental work), hormone fluctuations, and emotional stress can make people more prone to getting cankers.
  • Some people find that canker sores are triggered by foods and beverages such as chocolate, coffee, citrus, nuts, tomatoes, and acidic foods.
  • Additionally, certain mouthwashes and toothpaste seem to trigger cankers in a limited number of people.
  • Certain prescription medications
  • Vitamin deficiencies (most commonly Vitamin B12 deficiency), and other mineral deficiencies have been associated with cankers; however, vitamin supplements do not help to prevent recurrent episodes.
  • Mouth ulcers can be seen in patients with certain intestinal and auto-immune conditions; however, this is much less common and mouth sores are not usually the only sign of these types of conditions.

Is a Canker Sore the Same Thing as a Cold Sore?

No, they are NOT the same thing as cold sores, which are caused by the herpes virus and are contagious. Of note, a cold sore usually forms on the outside of the mouth, while canker sores always form on the inside of the lip or mouth.

How Do You Treat Canker Sores?

Cankers take about 1-2 weeks to heal and do not require treatment. A prescription steroid paste can help provide a barrier to the sore and soothe the area a bit, and topical anesthetics (such as lidocaine or benzocaine) can also provide some temporary relief.  Using a hydrogen peroxide mouth rinse can help cleanse the sore.   For severe ulcers, there are some medical procedures (such as cautery and injection) and oral medications that can help.  The best way to prevent a canker sore altogether is by reducing stress, sleeping well, eating a healthy diet, and avoiding triggers you have identified in the past.

When to Seek Medical Advice

  • If you are not sure that you have simple canker sores
  • If the sores are not healing, you have very large sores, or if you have very frequent outbreaks
  • If the sores are accompanied by a fever
  • If you are unable to eat or drink because of the pain

About The Author

Nathan Samuels, DNP, MSN, ANP-BC

Nathan Samuels, DNP, MSN, ANP-BC, is a board-certified adult nurse practitioner and a PCP at our Beverly practice. Dr. Samuels received a bachelor’s degree in neuroscience from Brandeis University and earned both his master’s degree in nursing and doctoral degree in nursing practice from Simmons College in Boston, MA.

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