

Mouth ulcers are painful sores in the oral mucous membrane. They usually have a diameter of three to four millimetres. They can be identified by the white or yellow centre with a red inflamed border. Mouth ulcers can appear in small or large numbers and usually disappear within one or two weeks. They occur on the inside of the lip, cheek, on or under the tongue, on the gums and rarely on the soft palate.
About 20% of the total population suffer from mouth ulcers. Mouth ulcers are most common among young children and adults in the 10 to 25 age group. 40% of the people suffering from mouth ulcers are below 11 years of age. The chance of suffering from mouth ulcers decreases after the age of 50. Mouth ulcers are rarely found in people over 40 years of age. People with a compromised immune system or an certain medication may suffer chronically from mouth ulcers.
Types of mouth ulcers
There are three types of mouth ulcers; minor ulcers (80% of the cases), major ulcers (10%) and herpetiform ulcers (10%).
Minor ulcers are the most common form of mouth ulcer, around 80% of all cases. They commonly have a diameter between 2 and 8 millimetres and are not bigger than 10mm in size. Minor ulcers appear singly and heal naturally within 7 to 14 days.
Major ulcers are less common, 10% of the cases. Major ulcers have a diameter greater than 10mm and usually, only one or two appear at a time. They are very painful and sensitive and may take anywhere between 10-30 days to heal and may leave a scar after they heal. Major ulcers are less common, around 10% of all mouth ulcers.
Herpetiform occur as multiple, pinhead-sized sores. The number of ulcers can range from five to 100. These tiny ulcers often fuse together to form larger, irregular shaped sores, which are very painful. Around 5-10% of mouth ulcers are herpetiform. Herpetiform ulcers are not related to the herpes virus.
Mouth ulcers can become a chronic problem and is referred to as recurrent oral ulcerations (ROU). People who suffer from recurrent oral ulceration have frequent outbreaks that appear every one or two weeks.
| Type of ROU | Symptoms | Duration |
| Minor ulcer | 1 to 5 mouth ulcers with a diameter of 3mm to a maximum of 10mm | 7 to 14 days |
| Major ulcer | 1 or 2 mouth ulcers with a diameter of 10mm or more | 14 to 30+ days |
| Herpetiform ulcer | 5 up to 100 mouth ulcers with a diameter of 1 to 3mm, appear in clusters or may form one large mouth ulcer | 7 to 14 days |
The cause of mouth ulcers
The exact cause of mouth ulcers is still unclear. Mouth ulcers often appear when the body's immune system is low, when mouth hygiene is poor or due to mouth injury. There are many factors that can cause mouth ulcers or trigger an outbreak. These factors differ from person to person. A person needs to investigate which factors may cause mouth ulcers so as to prevent (frequent) outbreaks, and then they can also use medication to relieve the symptoms. Factors that may cause or trigger mouth ulcers:
Symptoms
The ulcers begin as small oval or round red swellings on the skin in one of the locations described above. At this stage people will often feel a burning or tingling sensation. After one day the red swelling bursts open. The ruptured sores are covered by a thin white or yellow membrane and edged by a red inflamed border. Generally, the sores heal within two weeks without scarring. Mouth ulcers are usually found on the movable parts of the mouth, such as the tongue or the inside lining of the lips and cheeks, and at the base of the gums.
Mouth ulcers are easily identifiable by their appearance. A mouth ulcer will be:
Most mouth ulcers usually occur on:
It is rare to get a mouth ulcer on the roof of your mouth.