what causes mouth ulcers

Mouth ulcers can be annoying and painful, particularly if they keep coming back. But what causes them and are they anything to worry about?

By far the most common type of mouth ulcers are “aphthous ulcers”. These are the typical painful ones many of us have had at one time or another, when the lining of the mouth breaks down in a small round or oval area, often with a grey-yellow tinge. Spicy or acidic food can make this pain even more intense. While it’s often just a single lesion, it’s possible to get several ulcers at a time, and they may come back a few times per year.

What causes mouth ulcers?

It has been shown that some of the body’s “T cells”, which form an important part of the immune system, become more active and cause inflammation, leading to ulceration, though it’s not known what makes T cells behave in this way.

It seems certain things can trigger mouth ulcers. Low levels of Vitamin B12, iron or folate may cause thinning the lining of the mouth, making it easier for ulcers to form. Similarly, things that irritate the mouth in some way can act as a trigger.

• Biting the inside of your cheeks or other injuries to the mouth (for example during dental work or overly vigorous brushing of the teeth) may make it easier for an ulcer to form.
• Irritant ingredients present in toothpastes (such as sodium lauryl sulphate) could also a possible factor.
• High stress levels may affect the immune system- people often report getting more mouth ulcers when they’re run-down, around exam times and other stressful periods.
• Whilst there are some claims that mouth ulcers can relate to changes in hormonal levels in women, there is no clear evidence that menstruation, pregnancy or the contraceptive pill have any impact.
• Interestingly, aphthous ulcers are more common in women, tend to run in families and are less common in smokers- perhaps because smoking causes thickening of the lining of the mouth.
• They are not contagious, though some infections may look similar to mouth ulcers (e.g.the cold sore virus or hand foot and mouth disease) and these can be passed from person to person.

Less common causes of mouth ulcers

If mouth ulcers are frequent or severe, your doctor may consider tests to rule out more uncommon underlying causes. These include Coeliac Disease, Crohn’s disease or other forms of inflammatory bowel disease, Behcet’s disease and any conditions that affect the immune system, for example HIV or IgA deficiency.

There are also many other conditions than cause irritation, blisters or ulcers in the mouth- these are not the same as aphthous ulcers, but can look quite similar-examples include oral thrush, various viral or bacterial infections, and reactions to medications. Mouth cancer can have the appearance of an ulcer, but will tend to be slow-growing, often painless, and feel hard to touch

Treatment for mouth ulcers

The pain of aphthous ulcers can be relieved by using over-the-counter products from a chemist, such as barrier or anaesthetic gels. Sometimes your doctor may advise the use of a steroid inhaler- whilst these are normally breathed in by asthmatics, they may help to treat mouth ulcers if used as a spray into the mouth. Oral antibiotics may help in some cases. Nutritional deficiencies such as low iron, folic acid or Vitamin B12 should be corrected. Obviously if there is concern about any other underlying medical condition, identifying it and treating it appropriately may get rid of the mouth ulcers.

The good news is that, in most cases, aphthous ulcers get less frequent over time, and often stop completely.

If you have mouth ulcers and are not sure what is causing them, you should speak to your doctor to have the diagnosis confirmed

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