Diseases & Conditions

Mouth Ulcers

Mouth ulcers are painful sores inside the mouth. They appear as red, white or yellow lumps on the inner cheeks, roof of the mouth, gums, lips or tongue. They can make talking, eating and drinking uncomfortable.

There may be just one mouth ulcer present, or there may be several. Most mouth ulcers are harmless and will go away naturally, but some require treatment.

Sometimes, a mouth ulcer can indicate an underlying health concern, such as a virus, gastrointestinal issues or an autoimmune disease.

Mouth ulcers aren’t contagious. They are different from cold sores, which appear on the outside of the mouth. Cold sores are caused by a virus, and they are contagious.

Are there different types of mouth ulcers?

There are many different types of mouth sores and lesions, including:

Canker sores: The most common type, doctors aren’t sure of the cause of these mouth ulcers. They can appear during times of stress or if you accidentally bite or damage the inside of your mouth.

Erythroplakia: Caused by tobacco use, erythroplakia causes red patches usually appearing under the tongue or behind the lower front teeth. These lesions are often precancerous or cancerous.

Leukoplakia: Caused by an excess growth of cells in the mouth, leukoplakia causes grey or white patches. It may be caused by irritation from smoking or tobacco use and is usually non-cancerous.

Mouth cancer: Cancerous lesions in the mouth can appear as mouth sores. Usually red or white, these sores don’t heal by themselves. Always see a doctor if you have a mouth sore that hasn’t gone after a couple of weeks.

Oral lichen planus: An immune system response which causes an itchy rash and white sores. This condition usually affects women over 50.

Oral thrush: Caused by a fungal infection in the mouth, this leads to red or white sores and patches in the mouth. A yeast, called Candida albicans, overgrows which may be caused by taking antibiotics or a weakened immune system.

What are the symptoms of a mouth ulcer?

Mouth ulcers usually appear as sores inside the mouth (on the tongue, gums, inner lips, inner cheeks or the roof of the mouth. They are usually white, grey or yellow with a red edge.

Other symptoms may occur, including swelling and pain.

What causes mouth ulcers?

There are many different reasons a mouth ulcer may occur, including:

  • Eating food that is very acidic (such as pineapples, oranges or strawberries)
  • Vitamin or iron deficiencies
  • Viruses
  • Hormonal changes
  • Stress
  • Tiredness
  • Trauma or injury (from dental work or biting the inside of your mouth
  • Wearing braces on your teeth.

There are a number of health conditions that are associated with mouth ulcers, including:

  • Bacterial, viral or fungal infections
  • Behçet’s disease
  • Celiac disease
  • Crohn’s disease
  • Lupus
  • Reactive arthritis.
  • Vitamin deficiencies.

How are mouth ulcers diagnosed?

Your doctor can diagnose a mouth ulcer by examining you. If you have lots of mouth ulcers, they may order a blood test to diagnose or rule out an underlying health condition.

How are mouth ulcers treated?

You can buy over the counter medication that can help ease the pain of a mouth ulcer. Most mouth ulcers will go away by themselves, but the following may help them to heal:

  • Avoiding spicy food until the ulcer has healed
  • Rinsing your mouth with salt water
  • Staying hydrated
  • Using a topical anesthetic for mouth ulcers.

Your doctor may prescribe a steroid cream in severe cases. If an underlying autoimmune condition is diagnosed, they may prescribe immunosuppressants.

Mouth ulcers can’t be prevented, but the following may help to reduce the risk:

  • Eating a healthy diet with lots of fruit and vegetables.
  • Maintaining good oral hygiene (brushing your teeth every morning and evening, flossing and seeing a dentist regularly).
  • Using a soft toothbrush so you don’t irritate or damage the tissue in your mouth.
Mouth ulcers will usually go away by themselves. If you have an ulcer that hasn’t gone after a couple of weeks, always talk to your doctor.

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This page has been reviewed by a medical professional from Cleveland Clinic Abu Dhabi. Information on this page is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition.

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