Canker sores often run in families. They also are linked with other diseases, including Behcet's syndrome. You may have only one canker sore at a time, or many of them all at once. Most people get one, two or three sores at a time. But some people have 10 or more at a time. People who get canker sores typically have them a few times each year. Canker sores are not contagious.
Scientists don't know what causes canker sores. Most believe that there is a problem with the body's immune system. Emotional stress, menstruation or injury to the mouth are common triggers for simple canker sores. Certain foods such as citrus or acidic foods may trigger a canker sore or make one more uncomfortable.
Other conditions cause similar sores:
- Blood and immune system diseases, including HIV
- Vitamin and mineral deficiencies
- Crohn's disease
Canker sores are often confused with cold sores. Cold sores are caused by a virus.
About half of the population get canker sores. Smaller canker sores usually heal within a couple of weeks and do not leave scars. For most people, they are just annoying. But some people get larger canker sores (almost one-half inch across or larger). These take longer to heal. They can be painful, and may leave scars. These sores may be so uncomfortable that it is sometimes hard to eat or speak.
Sometimes a biopsy is needed to make sure the mouth sore is not a different disease. In a biopsy, the area is numbed and a small piece of tissue is removed. Then it is examined in a laboratory.
To reduce discomfort, you can:
- Eat bland foods
- Rinse with warm water
- Use pain-relieving gels or creams on the sores
People with larger or very painful sores may need steroid medicines. These are gels or creams that are placed on the sores. They make the sores heal faster. They also keep the sores from growing.
Other possible treatments include injected steroids. There are also a few medicines you can take by mouth, but this is for the most serious cases.
American Academy of Family Physicians
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