Canker Sores

  • Medical Author:
    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

  • Medical Editor: Jerry R. Balentine, DO, FACEP
    Jerry R. Balentine, DO, FACEP

    Jerry R. Balentine, DO, FACEP

    Dr. Balentine received his undergraduate degree from McDaniel College in Westminster, Maryland. He attended medical school at the Philadelphia College of Osteopathic Medicine graduating in1983. He completed his internship at St. Joseph's Hospital in Philadelphia and his Emergency Medicine residency at Lincoln Medical and Mental Health Center in the Bronx, where he served as chief resident.

A woman experiencing mouth and lip pain.

Canker sore definition and facts

  • Canker sores are small, painful ulcers on the inside of the mouth, tongue, lips, or throat.
  • Symptoms of canker sores include small, painful, crater-like ulcers.
  • See a doctor if canker sores are accompanied by fever, last more than three weeks, or the affected individual has difficulty swallowing.
  • Multiple factors may cause canker sores, including injury to the mouth, acidic or spicy foods, vitamin deficiencies, hormones, stress, or autoimmune disorders.
  • Canker sores are not the same thing as fever blisters (cold sores).
  • Most canker sores require no treatment and heal on their own.
  • To help relieve pain and speed healing, treatments and home remedies for canker sores include topical medications, mouthwashes, and over-the-counter pain medications.
  • People with frequent canker sores should see their doctor to get tested for possible underlying medical conditions.

Quick GuideTop Problems in Your Mouth

Top Problems in Your Mouth

Canker Sores (Mouth Sores) Symptoms

Some people may experience the following related canker sores symptoms and signs:

  • Bleeding Gums
  • Lump Or Mass On Gums
  • Painful Gums
A person with a canker sore on their lip.

What are canker sores, and what do they look like?

Canker sores (aphthous ulcers or aphthous stomatitis) are small, painful ulcers inside the mouth. They may occur on the tongue and on the inside linings of the cheeks, lips, and throat. They usually appear white, gray, or yellow in color, with a red border.

Canker sores are among the most common types of oral lesions, affecting about 20% of people. Women get canker sores more often than men. Canker sore susceptibility may be inherited, and the condition can run in families.

Canker sores are not the same as cold sores (fever blisters), which are an infection caused by the herpes virus and are contagious. Canker sores are not contagious, and are categorized into three types:

  1. Minor sores measure from 3 to 10 millimeters (mm) and are the most common type of canker sore. Lesions last 10 to 14 days and heal without scarring.
  2. Major sores are larger and deeper than minor sores, have an irregular border and a diameter of greater than 10 mm. Major canker sores may take weeks to months to heal and can leave a scar after healing.
  3. Herpetiform sores are characterized by large groups of multiple sores. These are small ulcers (2-3 mm) but there may be as many as 100 ulcers present at the same time. They tend to heal without scarring.
Picture of a canker sore (aphthous ulcer)
Picture of a canker sore (aphthous ulcer)
A stressed out woman sits to drink coffee.

What causes canker sores?

The cause of most canker sores is not well understood, and multiple factors may cause sores to appear. Some possible causes of canker sores include the following:

  • Injury to the mouth may cause simple canker sores. Injury could be from vigorous tooth brushing, dental work, braces or dentures, or a sports accident.
  • Acidic foods, including citrus fruits, may trigger a canker sore or make it worse.
  • Food sensitivities or allergies (anything from highly acidic foods to chocolate and coffee)
  • Diets low in vitamins B12, zinc, folate (folic acid), or iron
  • Toothpaste containing sodium lauryl sulfate
  • Allergy to certain bacteria in the mouth
  • Hormones
  • Emotional stress
  • Smoking
  • Gastrointestinal tract diseases such as Celiac disease or Crohn's disease
  • Autoimmune disorders such as systemic lupus erythematosus or Behçet's disease
  • Other immune system weakness such as a cold or the flu, HIV/AIDS, or an organ transplan
  • Systemic conditions such as Crohn’s disease or nutritional deficiencie
  • Oral cancer
  • Certain drugs may cause canker sores, including:
    • Aspirin
    • Nonsteroidal anti-inflammatory drugs (NSAIDs)
    • Beta-blockers
    • Oral nicotine
    • Chemotherapy medicines
    • Immunosuppressants
    • Penicillamine
    • Sulfa drugs
    • Phenytoin
    • Anticholinergic bronchodilators
    • Platelet aggregation inhibitors
    • Vasodilators
    • Protease inhibitors
    • Antibiotics
    • Antiretrovirals
    • Antihypertensives
Shocking Diseases of the Mouth
A image comparing a fever blister (cold sore) to a canker sore.

Are canker sores the same thing as cold sores (fever blisters)?

No, canker sores are not the same thing as fever blisters (cold sores).

Canker sores occur inside the mouth and are not contagious. Fever blisters are infections caused by the herpes simplex virus (HSV), they mostly occur on the lips and outside of the mouth, and they are very contagious.

A woman with her mouth open points to her inner cheek.

What are symptoms and signs of canker sores?

Canker sores are painful sores inside the mouth. They may occur on the tongue, the lining of the cheeks, the gums, the inside of the lips, or the soft palate on the back of the roof of your mouth. Common symptoms of canker sores include the following:

  • A burning, tingling, or prickling sensation, up to 24 hours before the sore appears
  • Crater-like ulcers that are white, gray, or yellow in color, with a red border
  • Sores are usually painful
  • Difficulty speaking, eating, or swallowing

Less common symptoms that can also indicate a more serious underlying infection include:

Contact your doctor or dentist if your canker sores are

  • Larger than usual
  • Spreading
  • Lasting more than three weeks
  • Causing severe pain even after taking over-the-counter pain medication
  • Causing difficulty drinking enough fluids to stay hydrated
  • Accompanied by fever
A woman swishes her mouth with an oral rinse.

What natural or home remedies cure canker sores?

In most cases, canker sores do not require any treatment, and there is nothing specific you need to do to get rid of a canker sore because it usually will heal on its own. If a person already has a canker sore, there are home remedies that can be used to help relieve the pain or irritation caused by the sore and to speed healing:

  1. Topical medications applied directly on the sore, mouthwashes, and oral medications can relieve pain or inflammation.
  2. Allow ice chips to dissolve slowly in your moth for relief of pain.
  3. Avoid acidic foods such as citrus fruits or spicy foods that may aggravate the sore.
  4. If there is any vitamin deficiency (a doctor can test for this), take supplementation as prescribed.
  5. Brush teeth gently and use a brush with soft bristles.
  6. Use toothpaste and mouthwash that does not contain sodium lauryl sulfate.
  7. Another home remedy is to mix milk of magnesia with Benadryl liquid and use as a mouth rinse.You can also dab milk of magnesia directly onto the canker sore with a cotton swab.
  8. Rinse your mouth with a salt water or baking soda rinse. Mix 1 teaspoon of baking soda per ½ cup water, and rinse.
  9. Other natural remedies include goldenseal mouth rinse, deglycyrrhizinated licorice (DGL) gargled in warm water, and saltwater rinses.
  10. Zinc lozenges may help provide relief and speed healing time. Do not give lozenges to young children, as they may be a choking risk.
  11. Vitamin C, vitamin B complex, and lysine can be taken orally when lesions first appear and may help speed healing.
  12. Infuse sage and chamomile herbs in water and use as a mouthwash four to six times daily.
  13. The herb Echinacea may help speed healing
  14. Carrot, celery, and cantaloupe juices may also be helpful.

Consult a health-care professional before using any home remedy as many have not been scientifically tested or proven effective.

A woman reaches for a tube of oral gel on the drug store shelf.

What topical prescription and over-the-counter (OTC) medications cure canker sores?

Topical gels or ointments are used for canker sores to relieve pain, decrease inflammation, and prevent infection.

Topical gels or ointments are used for canker sores to relieve pain, decrease inflammation, and prevent infection.

  • Topical pain medications: Gels such as benzocaine (Orajel, Orabase) and lidocaine (an anesthetic) are used directly on the canker sore to relieve pain or discomfort. Canker sore patches (Canker Cover) provide pain relief while covering and protecting the sore as it heals. These types of medications can be found over the counter.
    Topical anti-inflammatory medications: Steroid medications such as triamcinolone acetonide or fluocinonide can be used topically to decrease inflammation from canker sores. These medications usually require a prescription and should be used exactly as directed.
  • Topical antibiotics: These medications may be prescribed by your doctor or dentist if there is a possibility of the canker sore becoming infected with bacteria. Redness, crusting, pus discharge, or fever are signs of infection.

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A woman carefully pours mouthwash into a small cup.

What mouthwash solutions be used to treat and cure canker sores?

There are several mouthwash solutions that may be used to treat canker sore symptoms.

  • Diphenhydramine suspension (Benadryl Allergy liquid) is available over the counter and can be used as a mouth rinse because it has topical anesthetic effects on the tissue of the mouth and the canker sore. Put the suspension in your mouth, swish it around for 30 seconds to one minute, and spit it out. Do not swallow the rinse.
  • Anti-inflammatory steroid mouth rinses may be prescribed by your doctor or dentist to help reduce inflammation.
  • Tetracycline antibiotic rinses may be prescribed and have been shown to relieve the pain and promote healing of canker sores. Tetracycline should not be used by pregnant women, people allergic to tetracycline, or children under 16 years of age.
A woman describes canker sore pain to the dentist.

What oral medications are available to cure canker sores?

Several oral medications may help relieve symptoms of canker sores.

What should a person do if they get reccurent or chronic canker sores?

  • If a person suffers from frequent canker sores, there may be an underlying medical reason or illness that causes them. See a health-care professional or dentist if there are any concerns that canker sores are frequent.
  • Predisposition to canker sores may just be genetic. However, some diseases that affect the immune system such as lupus, Crohn's disease, celiac disease, or HIV/AIDS may cause frequent or recurrent canker sores.
  • Health-care professionals can order tests to determine if there is an underlying medical reason for a person's frequent canker sores.

Quick GuideTop Problems in Your Mouth

Top Problems in Your Mouth
Reviewed on 10/10/2016
References
REFERENCES:

Femiano, F., Lanza, Alessandro. et al. Guidelines for Diagnosis and Mangement of Aphthous and Stomatitis. The Pediatric Infectious Disease Journal. August 2007; vol 26: pp 728-732.

PubMedHealth.gov. Canker Sore.

University of Maryland Medical Center. Goldenseal.

University of Maryland Medical Center. Licorice.

WebMD.com. Canker Sores.

WebMD.com. Understanding Canker Sore Symptoms.

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