What is a mouth ulcer?

By Brooke Strickland


We’ve all had them.  They’re those small, painful sores on the inside of the mouth.  Women are prone to develop mouth sores more often and it is common to have a family history of them. 

The most common mouth ulcer is called a simple ulcer.  These are broken down into three different types. Minor ulcers are the most common type, are small, and do not scar the mouth and usually heal on their own.  Major ulcers are 1 cm or larger and have a raised texture to them.  These can also last longer, sometimes up to several months.  These are slower to heal and often cause difficulty eating.  The other type of mouth ulcers are called herpetiform ulcers, which are tiny sores that form in multiples. These are quite painful and can form together into one large sore.

These ulcers are usually round or oval and can be found on the floor of the mouth, on the inside of the lips or cheeks, or under the tongue. They can be especially painful when eating or drinking. 

What causes them?

It’s common to develop mouth ulcers by accidentally biting your cheek or by brushing your teeth too much or too rough.  In addition, if you have a sharp tooth or a filling that is rubbing or scratching against the cheek, mouth ulcers can form because of this friction. In addition, stress and anxiety can cause mouth ulcers to develop and medical conditions such as iron or vitamin B12 deficiency can cause them.  Further, some conditions such as Crohn’s disease, HIV, or viral infections can also be a trigger for the development of mouth ulcers.

There is usually no need to seek a doctor’s diagnosis for these.  However, if you have an ulcer that has lasted more than a few weeks, if they are getting progressively larger and/or more painful, or if you are developing ulcers on other parts of the body, you should seek a doctor’s advice.  Your doctor will likely check your vitamin and iron level in the body or collect a blood sample to make sure your overall health is ok.