Canker Sore

1 What is Canker Sore?

Canker sores, also known as aphthous ulcers, are small, painful, shallow ulcers that form in the mouth. Sores are usually white or yellow in color surrounded by reddish, inflamed tissues. They are seen at the base of the gums, tongue, lips or throat.


These sores are not contagious, and may resolve on their own within a week. Canker sores are of two types:

Simple canker sores – they persist for a week or two and appear three to four times a year.

Complex canker sores – these are less common when compared to simple canker sore and often appears in people who have a history of canker sores.

It is caused by multiple factors like injury, vitamin deficiency, or hormones. Frequent and large, persistent canker sores requires medical attention.

2 Symptoms

The main symptom of Canker sores is small, whitish or yellowish lesions surrounded by reddish, inflamed tissue. The sores are commonly found inside the cheeks, on or under the tongue, inside the lips, on the base of the gums, or on the palate.

  • Simple or minor canker sores are common and is characterized by small, oval-shaped lesion which heal without scarring in a week or two.
  • Complex or major canker sores are less common with large, deep lesions. The edges may be well-defined or irregular. Large ulcers usually have irregular edges. These are very painful and persist for more than six weeks. On healing these leave a scar on the skin.
  • Herpetiform canker sores develop later in life and are characterized by pinpoint lesions in the mouth. They may be found in clusters or join to form a large canker sore. Like complex sores, herpetiform sores also have irregular edges and persist for one or two weeks. They do not form scars on healing.

Large, recurring, and persistent sores require medical attention. Some people may have high fever associated with these lesions. Patients may also complain about pain while eating or swallowing.

3 Causes

Multiple factors can cause canker sores. It is more commonly found among females, teens and young adults. Family history of canker sores increases the risk of these lesions.

Some of the possible triggers of canker sores are:

  • Simple injuries caused by vigorous brushing, braces or dentures, or a cheek bite
  • Acidic foods like citrus fruits
  • Hygiene products like tooth pastes and mouth rinses that contain sodium lauryl sulphate
  • Sensitivity to food, including coffee, strawberries, cheese or nut
  • Vitamin B-12 or folate deficiency
  • Allergy to bacteria in mouth
  • Hormones
  • Emotional stress
  • Smoking
  • Helicobacter pylori
  • Gastrointestinal disorders like celiac disease or Crohn’s disease
  • Immune system disorder that attacks the soft tissue in the mouth
  • HIV/AIDS that suppress the immune system

4 Making A Diagnosis

Canker sores can be diagnosed without any specific tests. It is usually diagnosed by visual examination. Tests are recommended to check for other medical conditions that result in canker sores.

5 Treatment

Minor or simple canker sores do not require any specific treatment and resolve on their own within a week or so. Large, persistent canker sores may need medical attention.

Mouth rinses containing steroid dexamethasone help to reduce pain and inflammation associated with the lesion. Lidocaine also helps to reduce pain. A number of over-the-counter or prescription, topical applications are now available for faster healing of the sores. They are also helpful in reducing pain and inflammation. Products containing benzocaine, fluocinonide, and hydrogen peroxide are commonly prescribed or healing sores.

Severe sores that do not respond to topical treatments are treated with medications. These medications are usually used to treat the underlying conditions like gastrointestinal diseases. Oral steroid medications are also useful in treating large, painful sores.

Severe sores are sometimes destroyed by cautery. Topical solutions of debacterol is used for cauterizing large sores. This aids in healing the sores within few days. Silver nitrate is also used in chemical cauterization but may not expedite healing.

Sores caused by vitamin deficiency is treated with nutritional supplements.

6 Prevention

Avoiding foods that irritate the mouth helps to prevent the formation of canker sores. Having a healthy diet is essential for preventing nutritional deficiencies that lead to canker sores.

Good oral hygiene and reducing stress are also important. Covering the edges of dentures and braces with orthodontic wax protects the soft tissues from sharp edges.

7 Alternative and Homeopathic Remedies

Homeopathic remedies are used to reduce pain, inflammation, and also to improve healing of canker sores. Arsenicum album, borax, calcarea carbonica, hepar sulphuris calcareum, mercurius solubilis, natrum muriaticum, nux vomica, and Sulphur are some of the medications useful in alleviating the symptoms of canker sores.

Home remedies are equally useful in reducing mouth sores. This includes:

  • Peppermint and eucalyptus essential oil
  • Chamomile tea bags
  • Swish sage
  • Coconut oil
  • Clove oil
  • Honey rub
  • Wax cap
  • Cayenne cream
  • Aloe rinse
  • Yogurt
  • Warm salt water

8 Lifestyle and Coping

Lifestyle modifications are necessary in order to cope with canker sore.

Develop good oral habits like brushing teeth gently, using home-made mouth rinses, avoiding abrasive and spicy foods, and applying ice to prevent and relieve canker sores.

9 Risks and Complications

Fever, swollen glands, and difficulty in swallowing and eating are some of the complications of canker sores.