Health Library Logo

Health Library

Canker Sore

Overview

Mouth sores, also known as canker sores or aphthous ulcers, are small, open sores that appear inside your mouth. They can pop up on the inside of your cheeks, lips, tongue, under your tongue, at the base of your teeth where your gums meet, or on the soft part of the roof of your mouth. These sores often have a white or yellowish center surrounded by a red, inflamed area. This can make them quite painful, sometimes making it hard to eat or talk comfortably.

These sores usually aren't contagious, and they're different from cold sores, which appear on the outside of the lips. Most canker sores heal on their own within a week or two. However, if you notice a sore that's unusually large, painful, or just won't go away, it's a good idea to see your doctor or dentist. They can help figure out what's going on and make sure there aren't any underlying issues.

Symptoms

Mouth sores, also known as canker sores, are common. They're usually round or oval, with a white or yellowish center and a red ring around it. You'll typically find them inside your mouth, on or under your tongue, inside your cheeks or lips, near your gums, or on the soft part of the roof of your mouth. Sometimes, you might feel a tingling or burning sensation a day or two before the sore appears.

There are different types of canker sores:

  • Minor canker sores: These are the most common. They're small and oval-shaped, with a red border. They usually heal within one to two weeks without leaving any scars.

  • Major canker sores: Less common than minor sores, these are larger and deeper. They're typically round with defined edges, though sometimes, if very large, they might have uneven edges. Major sores can be very painful and take up to six weeks to heal, sometimes leaving noticeable scars.

  • Herpetiform canker sores: These are rare and often develop later in life. They're tiny and frequently cluster together in groups of 10 to 100 sores, which may combine into one larger sore. They have irregular edges and, like minor canker sores, usually heal within one to two weeks without scarring.

When to See a Doctor:

It's important to see a doctor if you have any of these concerns about your mouth sores:

  • Very large sores: If the sore is unusually big, it's best to see a doctor.
  • Recurring sores: If you have new sores appearing before older ones have healed, or if you have frequent outbreaks, see a doctor.
  • Persistent sores: If a sore lasts for more than two weeks, seek medical attention.
  • Sores on the lip edges: If a sore extends onto the part of your lip that is the same color as your lips, it's wise to get it checked by a doctor.
  • Uncontrolled pain: If you can't manage the pain with over-the-counter pain relievers, a doctor can help.
  • Trouble eating or drinking: Severe pain can make it hard to eat or drink. A doctor can address this.
  • Fever with sores: If you have a fever along with canker sores, it's essential to see a doctor.

When to See a Dentist:

If you suspect that sharp teeth or dental appliances are causing or worsening your mouth sores, consult your dentist. They can help identify and address any potential dental issues.

When to see a doctor

If you have mouth sores (canker sores), it's important to pay attention to their size, frequency, and duration. See a doctor if you notice any of these:

  • Large sores: Canker sores that are unusually big or wide.
  • Recurring sores: If you have sores that come back often, with new ones appearing before the old ones have healed, or if you have frequent outbreaks.
  • Long-lasting sores: Sores that don't go away after two weeks.
  • Sores on the lips: If a sore extends to the red part of your lips (the vermilion border).
  • Unbearable pain: If you can't manage the pain with home remedies.
  • Trouble eating or drinking: If the sores make it extremely difficult to eat or drink.
  • Fever with sores: If you have a high fever along with the canker sores.

If you suspect your canker sores might be linked to dental issues, like rough spots on your teeth or ill-fitting dental appliances, consult your dentist.

Causes

Canker sores are small, painful sores that appear inside the mouth. Scientists aren't completely sure what causes them, but they think it's often a mix of things. These sores can pop up even in the same person, seemingly for no apparent reason.

Several things might trigger a canker sore:

  • Mouth injuries: Rough brushing, dental work, sports injuries, or accidentally biting your cheek can all irritate the lining of your mouth, leading to a canker sore.
  • Certain mouth products: Some toothpastes and mouthwashes contain ingredients like sodium lauryl sulfate that can irritate the mouth and trigger sores in some people.
  • Food sensitivities: Some people react to certain foods, like chocolate, coffee, strawberries, eggs, nuts, cheese, spicy foods, or acidic foods. These foods can cause irritation and lead to canker sores.
  • Nutritional deficiencies: A lack of essential vitamins and minerals, such as vitamin B-12, zinc, folate (folic acid), or iron, might increase the risk of canker sores.
  • Allergies and infections: Some people might have allergic reactions to bacteria in their mouths. Also, the bacteria that cause peptic ulcers (Helicobacter pylori) might play a role.
  • Hormonal changes: Changes in hormone levels, such as during menstruation, can sometimes contribute to canker sore outbreaks.
  • Stress: Emotional stress can also be a factor.
  • Underlying health conditions: Certain conditions can increase the likelihood of canker sores. These include:
    • Celiac disease: This is a serious condition where the body reacts badly to gluten, a protein found in many grains.
    • Inflammatory bowel diseases (IBD): Conditions like Crohn's disease and ulcerative colitis, which cause inflammation in the digestive tract, can sometimes affect the mouth as well.
    • Behçet's disease: This rare condition causes inflammation throughout the body, including the mouth.
    • Immune system problems: Sometimes, the immune system mistakenly attacks healthy cells in the mouth, leading to canker sores.
    • HIV/AIDS: This condition weakens the immune system, increasing the risk of various mouth sores, including canker sores.

It's important to note that canker sores are different from cold sores. Cold sores are caused by the herpes simplex virus, while canker sores aren't.

Risk factors

Canker sores can affect anyone, but they're more frequently seen in teenagers and young adults, and women are more likely to get them.

People who get canker sores repeatedly sometimes have a family history of them. This could be because of shared genes (inherited traits) or because they share similar environmental factors, like particular foods or things they're allergic to.

Prevention

Canker sores often come back. But you might be able to have them less often by making some changes to your habits.

1. Pay attention to your diet: Some foods can irritate your mouth and make canker sores more likely. These include things like nuts, chips, pretzels, some seasonings, salty foods, and citrus fruits like oranges, grapefruit, and pineapple. Also, if you know you have allergies or sensitivities to certain foods, avoid them.

2. Eat a healthy diet: Eating plenty of fruits, vegetables, and whole grains is important for your overall health, and it can help prevent deficiencies that might make canker sores more frequent. A balanced diet gives your body the nutrients it needs to heal and stay strong.

3. Keep your mouth clean: Brushing your teeth regularly after meals and flossing once a day will help remove food particles that could be irritating your mouth. Use a soft-bristled toothbrush to prevent rubbing and irritating delicate tissues in your mouth. You might want to avoid toothpastes and mouthwashes containing sodium lauryl sulfate, as these can sometimes irritate some people's mouths.

4. Protect your mouth from extra irritation: If you have braces or other dental appliances, talk to your dentist about using orthodontic wax. This wax can cover any sharp edges that might rub against your mouth and cause sores.

5. Manage stress: If you think stress might be connected to your canker sores, look for ways to reduce stress. Meditation, deep breathing exercises, or guided imagery can be helpful tools. Finding healthy ways to manage stress can have a positive impact on your overall well-being, potentially reducing the frequency of canker sores.

Diagnosis

Canker sores don't require special tests to be diagnosed. A doctor or dentist can usually spot them just by looking. If you have a lot of canker sores or they keep coming back, your doctor might want to do some tests to check for other possible medical issues.

Treatment

Canker sores are small, painful sores in the mouth. Most of the time, they go away on their own within a week or two, and no treatment is needed. However, if a canker sore is large, persistent, or very painful, medical help might be necessary.

Several treatments are available:

Mouth Rinses: Your doctor might recommend a mouth rinse. Some rinses contain a steroid called dexamethasone, which can reduce pain and swelling. Other rinses contain lidocaine, which numbs the area and reduces pain.

Topical Products: These are creams, pastes, gels, or liquids that you apply directly to the sore. Many over-the-counter (OTC) and prescription options are available. Some common active ingredients include:

  • Benzocaine: This numbs the sore (brands include Anbesol, Kank-A, Orabase, and Zilactin-B).
  • Fluocinonide: This reduces inflammation (brands include Lidex and Vanos).
  • Hydrogen peroxide: This can help clean the sore (brands include Orajel Antiseptic Mouth Sore Rinse and Peroxyl).

There are also many topical products without active ingredients. Talk to your doctor or dentist to find the best option for you.

Oral Medications: If topical treatments don't work, your doctor might suggest oral medications. These could include:

  • Medications not specifically for canker sores: Examples include sucralfate (used to coat ulcers) and colchicine (used for gout).
  • Oral steroids: These are a last resort because of potential side effects. They are used only for very severe canker sores that don't respond to other treatments.

Cautery: Cautery uses heat or chemicals to destroy tissue. One example is a topical solution called Debacterol. It's used to treat canker sores and other mouth problems. It might speed healing, but more research is needed. Silver nitrate is another chemical cautery option, but it may not speed healing.

Nutritional Supplements: If you're not getting enough important nutrients like folate, vitamin B6, vitamin B12, or zinc, your doctor might recommend supplements.

Underlying Health Issues: If your canker sores are related to a more serious health problem, your doctor will treat the underlying condition.

When to See a Doctor: If your canker sores are severe, don't go away, or are accompanied by other symptoms, it's important to see a doctor or dentist.

(The following section is about a separate topic, email signup for Mayo Clinic):

To stay up-to-date on health information, you can sign up for email updates from Mayo Clinic. This service will provide you with research advancements, health tips, current health news, and expert advice on managing your health. Please provide a valid email address to subscribe. Mayo Clinic may use your email and website usage information, including protected health information if you're a patient, to provide you with relevant information. You can unsubscribe from these emails at any time.

Preparing for your appointment

A canker sore is usually diagnosed by a doctor or dentist just by looking at it. Here's how to prepare for your appointment.

Getting Ready for Your Appointment:

Before your visit, make a list of:

  • Your Symptoms: Note when the sore first appeared, and how it's changed since then. For example, has it gotten bigger, more painful, or lasted longer than usual?
  • All Medications: Include prescription drugs, over-the-counter medicine, vitamins, supplements, and any herbal remedies. Write down the dosage as well.
  • Other Medical Conditions: List any health problems you have, as they might be related to the sore.
  • Key Personal Information: Think about any recent stressful events, big life changes, or emotional factors that might be connected.

Questions to Ask Your Doctor or Dentist:

To make the appointment more helpful, prepare these questions:

  • Is this a canker sore? If so, what might have caused it? If not, what else could it be?
  • Do I need any tests? (Blood tests, etc.)
  • What treatment do you recommend?
  • What simple things can I do at home to relieve the pain?
  • Are there any ways to speed up the healing process?
  • How long will it take for the sore to go away?
  • What can I do to prevent this from happening again?

Don't be shy about asking any other questions that come up during your appointment.

What to Expect From Your Doctor or Dentist:

Be ready to answer questions like these:

  • What are your symptoms? (Describe the pain, location, and appearance.)
  • When did you notice the symptoms?
  • How bad is the pain? (Use a scale if you have one.)
  • Have you had similar sores before? If so, did anything seem to trigger them?
  • Have you been treated for similar sores in the past? If so, what worked best?
  • Have you had any dental work recently?
  • Have you had any major stress or life changes recently?
  • What's your typical diet like?
  • Do you have any other medical conditions?
  • What medications are you taking? (Include all prescription, over-the-counter, vitamins, and supplements.)
  • Does anyone in your family have a history of canker sores?

By being prepared with this information, you can help your doctor or dentist diagnose the problem and create a treatment plan that works best for you.

Address: 506/507, 1st Main Rd, Murugeshpalya, K R Garden, Bengaluru, Karnataka 560075

Disclaimer: August is a health information platform and its responses don't constitute medical advise. Always consult with a licenced medical professional near you before making any changes.

Made in India, for the world