Overview

From the moment we put food into our mouths, the process to digest this food and absorb the nutrients it contains begins. Sometimes, like many of us have experienced, we can get sores in our mouth that can make chewing food quite painful. In this article, we will be looking at what mouth ulcers are and examining what causes them.  

Mouth ulcers

What are mouth ulcers?

Mouth ulcers are a result of damage to the surface of parts of the inner mouth. This could include the inner cheek, lips, floor of the mouth and the surface of the tongue. It is painful, especially when eating or talking, usually white in colour and could vary in size from anywhere between 3 to 10cm. If it clears up within two weeks, it is an acute ulcer. If it lasts longer than this, then it’s a chronic ulcer. Although it is common, children tend to get ulcers more often than adults do.¹

Causes and treatment of mouth ulcers

Pinpointing the exact cause of ulcers can be quite difficult, as there is a wide range of causes, making diagnosis challenging. For example, it can be caused by something as simple as accidentally biting a part of your inner mouth, brushing your teeth roughly or wearing braces, or if you drink something hot that causes a burn in your mouth, this could lead to the formation of an ulcer. Some people are also genetically more susceptible, meaning ulcers are common in their family. Other causes include medications (certain medicines can cause ulcers), infections, nutritional deficiencies and gastrointestinal (digestive) disorders.¹

Since a lot of mouth ulcers have mechanical causes, they tend to clear up on their own within 2 weeks, and you can use painkillers or topical medications from the pharmacy to help manage the pain. However, if it lasts longer than 3 weeks, if you get ulcers frequently (recurrent ulcers) or there is also blood and pus, you should go and see the GP in case the ulcer is indicative of an infection, gastrointestinal disorder or deficiency.²

The relationship between mouth ulcers and digestive health

You often hear people say, ‘you are what you eat,’ and they’re not wrong. Having a good, balanced diet is really important for maintaining good health. We know ulcers can make eating quite painful, so perhaps somebody with an ulcer may not be able to eat as they normally do, negatively impacting their diet for the week or two they have the ulcer(s) for or longer if they have a recurrent ulcer. However, ulcers can also indicate an existing vitamin deficiency or a gastrointestinal disorder. Coeliac disease, Crohn’s disease and ulcerative colitis are amongst the GI disorders that commonly have mouth ulcers as a symptom. Let’s look at this in more detail.

Vitamin deficiencies and mouth ulcers

Vitamins are essential nutrients and can be categorised into two groups: fat-soluble and water-soluble. Vitamin deficiency, which is also known as hypovitaminosis, is caused by either a low intake of vitamins, a result of poor diet or limited exposure to the sun (a source of vitamin D) or impaired absorption, for example, due to Coeliac disease.³

Coeliac disease and mouth ulcers

Individuals with coeliac disease (CD) have an intolerance to gluten, which is a very common food intolerance. In this, consuming foods containing gluten damages the small intestines, making it more difficult to absorb nutrients. The most common symptoms tend to be diarrhoea, a bloated abdomen and overall weight loss, but recurrent mouth ulcers can also be a symptom. Since there are around 20% of CD patients tend to have vitamin deficiencies, a possible explanation for mouth ulcer occurrence is the damage to the small intestines, resulting in fewer vitamins being absorbed through diet. Interestingly, however, there are some studies that believe there is no real link between mouth ulcers and CD, so the 20% statistic may merely be a coincidence.⁴

Mouth ulcers as a sign of ulcerative colitis

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) where the colon and rectum are inflamed. And although the primary symptoms are gastrointestinal, many UC patients have mouth ulcers before the gastrointestinal symptoms begin, so perhaps analysing these can help with earlier diagnosis of UC.⁵ 

Crohn’s disease and mouth ulcers

Like ulcerative colitis (UC), Crohn’s disease is categorised as an inflammatory bowel disease.⁵ If someone has Crohn’s disease, they have chronic inflammation of any part of the GI tract. The exact cause of this is unknown, although some proposed causes include genetics, alterations in the gut microbiome (the natural microorganisms found in the gut) and dysregulation of the immune system.⁶

And again, like in UC, Crohn’s disease patients tend to have oral symptoms as well as gastrointestinal ones. These symptoms include swelling of the lips and, of course, mouth ulcers. The ulcers are, however, more commonly found in paediatric CD patients than in adults and can be the first sign/symptom of CD that these patients face. Based on this, a study has suggested carrying out a test on what microorganisms are found in a CD patient’s saliva. If there are common microorganisms in the saliva of those with CD, this could potentially be used to diagnose Crohn’s disease in the future. If more research supports this, then perhaps it could be a great alternative to stool tests, which many people understandably don’t feel comfortable having.⁶

Summary

Mouth ulcers are very common, and we have almost likely had them at some point in our lives. However, mouth ulcers can also indicate an underlying gastrointestinal problem. More research needs to be done in the future to confirm this link and look at the potential to use this information to come up with better diagnostic tests for diseases such as Crohn’s disease and ulcerative colitis. Thank you for reading.