Canker Sores

Canker sores — or aphthous ulcers — are small ulcers in the lining of your mouth. A canker sore looks like a white or yellowish mouth sore with a red border. You usually get it at the base of your gums, on or under your tongue, or inside your lips or cheeks.

There are different types:

• Minor canker sores are most common. They’re usually less than one centimeter in diameter (smaller than a pea). They heal within a few weeks without scarring.
• Major canker sores are usually bigger than one centimeter, extremely painful and often leave behind scars. They can take months to heal.
• Herpetiform canker sores are rare. Instead of one sore, tiny pinpoint sores often cluster together. This kind heals within about two weeks and doesn’t usually cause scarring.

These sores are common, and they usually go away without treatment. But they can make eating and talking uncomfortable in the meantime. Luckily, there are things you can do to ease the discomfort of a canker sore.

Symptoms of canker sores

Common symptoms include:

• Burning or tingling in your mouth (a sign that a canker sore is forming)
• One or more painful sores on your tongue, the inside of your lips, your inner cheeks or the roof of your mouth
• Small, round ulcers that are white, gray or yellow with a red border

Canker sore causes

Experts aren’t sure what causes canker sores. They do know that they’re not contagious. Some people confuse canker sores with cold sores, which are caused by a contagious virus. But canker sores and cold sores aren’t the same.

There are several potential causes of a canker sore, including:

• Conditions that involve a weak or dysregulated immune system, like celiac disease, HIV/AIDS and inflammatory bowel disease
• Medication side effects from taking beta-blockers, immunosuppressants or NSAIDs
• Nutritional deficiencies, especially a lack of Vitamins B12 and D, folate, iron or zinc
• Your genes, which may predispose you based on your DNA (canker sores run in families)

Experts have identified factors that can trigger the development of these ulcers, including:

• Consuming certain foods and drinks (including acidic foods, spicy foods, caffeine, eggs, cheese, peanuts and almonds)
• Changing hormone levels during your period
• Injury to the inside of your mouth (like biting your cheek or scrapes from ill-fitting dental appliances)
• Toothpastes that contain sodium lauryl sulfate
• Stress

Risk factors

Anybody can develop one. But they’re most common in teens and people in their 20s. Females are more likely than males to get them. Experts believe this could be related to hormone differences.

It’s common to get a canker sore at an early age and then get them throughout your life. But it’s unusual to get your first canker sore after age 40.

How to lower your risk

There’s no surefire way to prevent canker sores. But if you’ve had them before and want to keep from getting new ones, try to notice triggers that cause them. As best as you can, avoid these triggers.

Here are some general tips that work for lots of people who get canker sores:

• Practice good oral hygiene. Use a soft-bristled toothbrush and waxed floss to prevent injury.
• Steer clear of acidic, salty, spicy or other “trigger” foods.
• Talk to your healthcare provider about potential nutritional deficiencies.
• Try a “canker sore toothpaste” that doesn’t contain sodium lauryl sulfate. Your dental care provider can recommend brands.
• Try stress reduction techniques, like mindfulness and meditation.

How doctors diagnose canker sores

Your healthcare provider can diagnose canker sores during a physical exam. They’re easy for providers to identify just by looking. They might also recommend a blood test to see if you have another condition that’s causing the ulcers.

How do you heal a canker sore fast?

Canker sore treatment may include over-the-counter (OTC) or prescription products to ease your symptoms. Some may help you get rid of the sore faster. Your healthcare provider may recommend one or more of these remedies:

• Topical anesthetics, like benzocaine (found in OTC products like Orajel^™ and Anbesol^®)
• OTC mouth rinses that don’t contain alcohol
• Prescription mouth rinses like magic mouthwash, or rinses containing chlorhexidine or dexamethasone
• Corticosteroid ointments, like fluocinonide, beclomethasone or hydrocortisone hemosuccinate
• Corticosteroids you take by mouth, like prednisone (if the sore doesn’t get better with the ointment)
• Vitamins or supplements, if you have canker sores related to a nutritional deficiency

For severe canker sores, your healthcare provider may recommend laser therapy or electrocauterization. This can get rid of germs in the area, reduce pain and speed up healing.

Does salt on a canker sore help?

Rinsing your mouth with saltwater or a mild mouthwash can help ease the pain. Another option is to use a cotton swab to dab a mixture that’s equal parts water and part hydrogen peroxide onto your sore. (Take care not to swallow the hydrogen peroxide.) Follow by dabbing a small amount of milk of magnesia on it.

You can do this up to four times a day for canker sore pain relief.

When should I see my healthcare provider?

Most canker sores go away on their own without treatment. So, you may not need to see your provider. But you should definitely give them a call if you have canker sores that:

• Last longer than two weeks
• Come with flu-like symptoms
• Are larger than a centimeter (bigger than a pea)
• Come back two or three times a year
• Interfere with eating, drinking or other daily routines

These signs may mean you have a condition causing your sores that your provider needs to know about. Or your provider may want to do testing to be 100% sure that the growth is a canker sore and not something serious.

How long do canker sores last?

Canker sore pain usually improves in a few days. The ulcers typically heal within two weeks, even without treatment. If you have a canker sore that lasts for more than two weeks, schedule an appointment with your healthcare provider.