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Mouth ulcer

Dr Roger Henderson
Reviewed by Roger HendersonReviewed on 29.04.2024 | 4 minutes read

A mouth ulcer occurs when a part of the lining of the inside of your mouth becomes damaged. The area that hurts is known as a mouth ulcer. They are very common and can be caused by many different things. The majority are not caused by anything serious and usually improve within 2 weeks. They look like red and white lesions on the inside of your cheeks that are usually 1cm in size or less. You can sometimes get larger mouth ulcers which are bigger than this and they can also appear at the bottom of the gums, under or on the tongue.

Most people have at least one attack of mouth ulcers in their life but they are more common in women and under the age of 40. They cannot be passed on by kissing or sharing utensils. Unfortunately, up to 1 in 5 people have recurrent attacks of mouth ulcers.

Over a third of people with recurrent mouth ulcers have a family history of it and this figure rises to over 80% if both parents suffered from recurrent mouth ulcers. Certain medical conditions can also predispose to chronic mouth ulcers developing, such as;

  • Vitamin B12 deficiency.
  • Viral infections – a very common trigger for mouth ulcers.
  • Iron deficiency.
  • Coeliac disease (intolerance to a protein called gluten, found in wheat, rye and barley).
  • Crohn's disease.
  • Reiter's syndrome.
  • HIV infection.

Occasionally, mouth ulcers can be linked to medication and common examples include;

  • Painkillers such as ibuprofen and aspirin.
  • Nicorandil and beta blockers – both used in heart conditions.

What causes them?

The most common cause is an injury to the inside of the mouth which can be through accidentally biting it, dentures or braces rubbing on the mouth, eating or drinking food that is too hot or too acidic, and any injury with a rough or sharp object. Other causes can be due to stress, vitamin deficiencies, pregnancy, some medication, inflammatory conditions, and in very rare cases mouth cancer (ulcers due to this don’t heal and are more likely to be around the tongue area.) You are also more likely to develop mouth ulcers if your family members suffer from mouth ulcers, you have a lowered immune system or you have just stopped smoking. Mouth ulcers are not contagious.

Healthwords pharmacists' top tips

There are things you can do to help with your mouth ulcer. These include avoiding using stiff toothbrushes, abrasive mouthwashes, hard or sharp food such as crisps, and acidic or spicy foods. You can also get over-the-counter medicines that can help relieve pain and can sometimes shorten the healing time. Examples of these are lozenges, gel, liquids, sprays and antimicrobial mouthwash. You can speak with your local pharmacist if you are unsure which is right for you.

When should I see my doctor?

You should see your doctor if you are having any other symptoms along with mouth ulcers such as fatigue and stomach pain. If your mouth ulcers persist for more than three weeks, especially if they are very painful or severe, your doctor may choose to refer you to a specialist at your local hospital. You will also be referred if you have persisting abnormal-looking areas of ulceration which bleed. This is because in a very small number of cases, this may be a sign of oral cancer.

You are more at risk of developing mouth cancer if you are a male smoker aged over 45 or a heavy drinker. Because the recovery rate for mouth cancer is good if spotted early enough, it is important to not only get any persisting mouth ulcers checked out but also to have regular check-ups with your dentist.

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Dr Roger Henderson
Reviewed by Roger Henderson
Reviewed on 29.04.2024
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