What is a canker sore, anyway? Read how to help heal those unwelcome, painful sores.

By Brittany Loggins
October 02, 2019

We’ve all had them: canker sores. You know the ones, those round, painful little sores you get on the inside of your mouth. One of the major problems with canker sores is that, while they’re super uncomfortable, the general advice most people receive is to wait for them to heal on their own. But to find out more about what causes canker sores and how to get rid of them at home, I spoke to Vidya Sankar, DMD, an assistant professor of oral medicine, infection, and immunity at the Harvard School of Dentist Medicine and a member of the American Academy of Oral Medicine executive committee.

What Causes Canker Sores?

The short answer is that doctors aren’t super sure—but there are plenty of things that could be behind these annoying little wounds. “The pathogenesis (read: the cause of canker sores) is unknown. It’s really thought to be associated with a few predisposing factors that can be genetic, stress-induced, related to nutritional deficiencies, some disturbances in the immune system, hypersensitivities, or allergic reactions to products,” Dr. Sankar explains. “But there’s no well-known one-entity cause of these lesions.”

That said, stress could be a big contributing factor. “When life stressors get in the sway, such as new jobs, work, or family relationships, people who used to get canker sores as a young kid may start to experience them again because those triggers come into play later on in life,” Dr. Sankar says.

It’s also possible—though less likely—that these ulcers are being caused by nutritional deficiencies. Regardless, if you’re experiencing lots of them at once, it might be time to go to an oral specialist.

“Oral medicine specialists are the ones who are very well-versed with canker sores in the mouth,” Dr. Sankar says. “They can distinguish between those that are idiopathic (a more spontaneous, one-time thing) or those that can be attributed to systemic diseases or nutritional deficiencies.”

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Canker Sore Treatments, Remedies, and Relief

While there’s no way to make canker sores magically disappear, there are products that can relieve some of the pain. “Products you can purchase are things like topical anesthetics you can rub on it—all they really do is numb the area,” Dr. Sankar says. “There are some products that are marketed as a coating agent that kind of seals over the area, so if you have a canker sore next to a tooth, it kind of seals over the ulcer so it’s less painful.”

In addition to over-the-counter options, warm salt water rinses can be helpful in keeping the mouth clean, which will help the canker sore heal faster and keep it from getting worse.

“It’s not bacteria or yeast that’s causing these ulcers, but once you have a break in the skin, these organisms can come in and occupy it,” says Dr. Sankar. “The cleaner you keep your mouth, the faster an ulcer can heal, so the warm salt water rinses may definitely be helpful.”

There are also prescription mouthwashes that can be prescribed by your doctor, says Dr. Sankar, and patients should visit the American Academy of Oral Medicine’s page for more information.

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