What is a mouth ulcer?

Mouth ulcers, or canker sores, are blisters that appear in the lining of the mouth and tongue. There is no cure for canker sores, but painkillers, antimicrobial mouthwash, numbing sprays and corticosteroid lozenges may provide relief.
Mouth ulcers, or canker sores, are blisters that appear in the lining of the mouth and tongue. There is no cure for canker sores, but painkillers, antimicrobial mouthwash, numbing sprays and corticosteroid lozenges may provide relief.

Many people get mouth ulcers sometimes called canker sores or aphthous ulcers. These are a sore or blister that appears in the lining of the mouth and sometimes on the tongue. Mouth ulcers are not serious and usually clear up on their own.

A mouth ulcer is a hole in the lining of the mouth that develops when the top layer of cells breaks down. Some may be red, but some can also turn white as dead cells and food get in the center. A blister can also appear as a raised sore filled with clear fluid. 

Symptoms

Some symptoms of mouth ulcers include:

  • Blister or sore with a red border and white center
  • Found inside the mouth on the lips, cheeks, tongue, and roof of mouth
  • Pain even when you’re not eating
  • Pain when you eat certain foods like citrus fruits or spicy foods
  • Tingling, burning, or rough feeling as the blister develops
  • One sore or two or three together

Mouth ulcers are often confused with cold sores. However, cold sores are caused by the herpes simplex virus and appear on the outside of the mouth around the lips. 

Causes of mouth ulcers

Experts don’t know the exact reason why people develop mouth ulcers, but there may be some things that contribute. These may include:

Who can get mouth ulcers

Anyone can get mouth ulcers, but women are more likely to develop mouth ulcers, especially while pregnant or during the menstrual cycle. While children can develop a mouth ulcer, most people develop them for the first time as a teenager or young adult. 

People being treated with chemotherapy may develop mouth ulcers. It can range from some sores to severe inflammation, bleeding, and ulceration called mucositis.

Diagnosis for mouth ulcers

You may not need to see your doctor about a mouth sore unless they are persistent, you have other symptoms, or you are feeling very unwell. Your doctor will take your personal and medical history and do a physical exam to look at your sores. 

Your doctor may look to see if you have large white patches on the roof of your mouth to rule out an infection called thrush or for signs of other conditions.

Your dentist can also examine your mouth and diagnose your mouth ulcers during annual checkups and cleanings. 

Remedies for mouth ulcers

There are no quick fixes for mouth blisters as they need time to heal, but they will usually resolve on their own without treatment. The blisters may be sore for seven to 10 days. Minor blisters will heal in one to two weeks, but major canker sores can take up to four weeks. 

While mouth blisters usually heal on their own without treatment, you may be uncomfortable and feel pain. You can manage your mouth blisters at home with over-the-counter medications and self-care practices.

What treatments can help?

You can manage your symptoms with some over-the-counter medications, including:

If your canker sores are very uncomfortable, or persistent and don’t respond to home treatment, your doctor may prescribe steroid cream to rub on the blister or canker sore and a prescription mouthwash. They may also recommend vitamins if you are lacking vitamin B12 and iron.

What are some natural home remedies for mouth ulcers?

Managing your symptoms at home will help your blisters heal and ease your discomfort. There are some natural home remedies you can try, including:

  • Rinse your mouth with warm saltwater
  • Drink cold fluids instead of hot drinks like coffee or tea
  • Eat popsicles
  • Numb the sore with an ice cube or suck on ice
  • Eat soft, bland foods 
  • Use a toothbrush with soft bristles
  • Apply a thin paste of baking soda and water to the blister
  • Apply hydrogen peroxide and water to the blister
  • Apply milk of magnesia to the blister

What are some alternative therapies for mouth ulcers?

Low level laser therapy can relieve mouth blisters in severe or chronic situations.

Risks and outlook

Mouth ulcers generally are not serious and heal on their own without treatment. However, you may need to see your doctor if:

  • You have trouble eating or drinking
  • They keep coming back
  • You are feeling very unwell
  • You have other symptoms
  • They don’t respond to treatment
  • They become more painful and red

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Medically Reviewed on 1/28/2021
References
SOURCES:

American Cancer Society: "Mouth Sores and Pain."

InformedHealth.org, Institute for Quality and Efficiency in Health Care, 2006.

MedlinePlus: "Canker sore."

Merck Manual: "Mouth Sores and Inflammation."

National Health Service: "Mouth ulcers."

The Pan African Medical Journal: "Low laser therapy as an effective treatment of recurrent aphthous ulcers: a clinical case reporting two locations."