Diagnosis

Tests aren't needed to diagnose canker sores. Your healthcare professional or dentist can diagnose canker sores by talking with you about your symptoms and looking in your mouth. If your canker sores are severe, don't go away or happen often, or if you have other symptoms, you may need tests to check for other health conditions.

Treatment

Treatment usually isn't needed for minor canker sores. These tend to heal on their own in 1 to 2 weeks. You may need treatment if sores are large, do not heal or are very painful. Treatment may include mouth rinses, topical products, oral medicine, cautery of the sores or nutritional supplements. Or treatment for related health conditions may be needed.

Mouth rinses

If you have several canker sores, your healthcare professional may prescribe a mouth rinse that has the steroid dexamethasone (dek-suh-METH-uh-sown). This can lessen pain and swelling. A rinse that has lidocaine, a numbing medicine, can lessen pain.

Topical products

Prescription products and products you can buy without a prescription may help ease pain and speed healing. These include pastes, creams, gels or liquids that you put on the canker sore as soon as it appears.

Common active ingredients in topical products include:

  • Benzocaine (Anbesol, Kank-A, Zilactin-B).
  • Fluocinonide (Vanos).
  • Hydrogen peroxide (Orajel Antiseptic Mouth Sore Rinse, Peroxyl Mouth Sore Rinse).

There are many other topical products for canker sores, including those without active ingredients. Ask your healthcare professional or dentist for advice on which may work best for you.

Oral medicines

Oral medicines may be used when canker sores are severe or don't heal with topical treatments. These may include:

  • Medicines not intended specifically for canker sore treatment. Examples include colchicine used to treat gout and the intestinal ulcer treatment sucralfate (Carafate), a coating agent.
  • Oral steroid medicines when severe canker sores don't heal with other treatments. Because of the potential for serious side effects, they're usually not the first treatment choice.

Cautery of sores

During cautery, tissue is burned away to get rid of the canker sore. Chemical cautery uses a substance placed on the canker sore. Low-level laser therapy also is an option. Cautery is used for more-painful or more-severe canker sores, especially to lessen pain.

Nutritional supplements

If testing shows that you have low levels of important nutrients, such as folate, vitamin B-6, vitamin B-12, or zinc, your healthcare professional may suggest a nutritional supplement.

Related health conditions

If a medical condition is causing your canker sores, your healthcare professional can treat the health condition.

Self-care

To help lessen pain and speed healing of canker sores, these tips may help:

  • Rinse your mouth. Use a saltwater or a baking soda rinse several times a day. For a saltwater rinse, mix 1/2 teaspoon (2.5 milliliters) of table salt in 8 ounces (237 milliliters) of warm water. To make a baking soda rinse, mix 1 teaspoon (5 milliliters) of baking soda in 1/2 cup (118 milliliters) warm water.
  • Put a small amount of milk of magnesia on your canker sore a few times a day.
  • Stay away from foods that are rough, acidic or spicy. These can cause more irritation and pain.
  • Allow ice chips to slowly dissolve over the canker sores.
  • Brush your teeth gently. Use a soft toothbrush and a toothpaste without a foaming agent such as Biotene or Sensodyne Pronamel.

Preparing for your appointment

Your healthcare professional or dentist diagnoses a canker sore based on your symptoms, medical history and how the sore looks. Here's some information to help you get ready for your appointment.

Before your appointment make a list of:

  • Your symptoms, including when they started and if they've changed or worsened over time.
  • All medicines you're taking, including vitamins, herbs and other supplements, and the doses.
  • Other health conditions you have, if any.
  • Key personal information, including any recent changes or stress in your life.
  • Questions to ask your healthcare professional or dentist.

Some basic questions to ask:

  • Do I have a canker sore? If not, what else could it be?
  • What factors may be causing the sore?
  • Do I need any tests?
  • What treatment do you recommend, if any?
  • What can I do to lessen pain? Is there anything I can do to speed up healing?
  • How soon do you think my symptoms will get better?
  • Is there anything I can do to keep from having another canker sore?

Feel free to ask other questions during your appointment.

What to expect from your healthcare professional or dentist

You may be asked:

  • What are your symptoms?
  • When did you first notice these symptoms?
  • How severe is your pain?
  • Have you had sores like this in the past? If so, have you noticed if anything seems to trigger them?
  • Have you been treated for sores like this in the past? If so, what treatment worked best?

You also may be asked about possible triggers:

  • Have you had any recent dental work?
  • Have you recently had a lot of stress or major life changes?
  • What is your typical daily diet?
  • Have you been diagnosed with any other medical conditions?
  • What medicines do you take?
  • Do other family members also have canker sores?

Be ready to answer questions so that you'll have time to talk about what's most important to you.

By Mayo Clinic Staff