Canker Sore - Symptoms, Risk factors and Treatment

Canker sores, also known as mouth ulcers, are painful ulcers in the mouth. They are not harmful but can be discomforting, especially when you brush your teeth, drink, or eat something. Mostly mouth ulcers go away on their own in two weeks. 

Canker Sores Causes

The exact cause of mouth ulcers is unknown. But some factors can aggravate it, such as;

  • Quitting smoking

  • Eating acidic or citrus foods

  • Eating spicy foods

  • Biting inside of the cheek

  • Biting your tongue

  • Wearing braces or poorly fitting dentures

  • Wearing some apparatus that rubs against your gums or cheek

  • Hormonal changes such as pregnancy, menopause, or puberty

  • Stress or anxiety

  • Hand, foot, and mouth disease

  • Radiation or chemotherapy

  • Autoimmune disorders

  • Bleeding disorders

  • A deficient filling

  • Over-the-counter or prescription medications such as beta-blockers or painkillers

  • Nutritional deficiencies from diseases such as Crohn’s disease, iron deficiency, vitamin B 12 deficiency

  • Weakened immunity due to long term immunosuppressant intake such as corticosteroids or health conditions that weaken immunity

  • Gingivostomatitis 

  • Infectious mononucleosis

  • Oral thrush

  • Cancer

  • Celiac disease

  • Bacterial, viral, or fungal infection

Canker Sores Types  

Mouth ulcers can be classified as;

  • Minor 

  • Major 

  • Herpetiform 

Minor mouth ulcer

They are small and oval mouth ulcers that cause no scarring and heals within one to two weeks on their own. 


They are deeper and larger than minor mouth ulcers having irregular edges. They may take up to 6 weeks to heal up and can cause scarring. 


It resembles the mouth ulcers caused by the herpes virus, but in actual it is different. Like herpes stomatitis, they are not contagious. They are pinpoint and occur in clusters in 10 to 100 in numbers. Often they heal on their own within one to two weeks and have irregular edges. 

Canker Sores Prevention 

To prevent mouth ulcers, the following tips may help;

  • Chew food slowly

  • Avoid very hot food and drinks

  • Practice regular dental hygiene

  • Use a soft toothbrush

  • Visit your dentist often

  • Do not overstress yourself

  • Eat a balanced diet

  • Stop eating spicy food

  • Taking multivitamins daily, especially vitamin C and B vitamins

  • Do not smoke

  • Drink plenty of water

  • Take an antifungal if you have oral thrush

  • Avoid alcohol consumption

  • Use lip balm when in sunlight

Canker Sores Treatment 

If the pain does not subside with an over-the-counter pain reliever, the healthcare provider may prescribe lidocaine- a local anesthetic to be applied to the ulcers. However, it should be used with extreme caution in the oral cavity because it can cause numbness, choking, or swallowing difficulties. 


Mouth ulcers, also known as canker sores, are painful ulcers in the mouth. They are not harmful but can be discomforting, especially when you brush your teeth, drink, or eat something. Mostly it can occur due to nutritional deficiency, therefore, you should incorporate multivitamins in your diet.

Doctors For Canker Sore

Dr. Amjad Aziz

General Physician

14 Years

Dr. Amail Khattak

General Physician

7 Years

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