Canker sores
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What are recurrent canker sores?

Canker sores are small, white sores inside your mouth where the top layer of the skin is damaged. They are very sore but usually don't last long.

If you keep getting bouts of canker sores every few months, weeks or even every few days, doctors say you have recurrent canker sores.
 
 
 
 
 
Source:
Porter SR, Scully C, Pedersen A.
Recurrent aphthous stomatitis.
Critical Reviews in Oral Biology and Medicine. 1998; 9: 306-321.
 
 
 
 
 
1 You may also hear them called aphthous ulcers.

Canker sores are small, white sores inside your mouth.

Doctors divide recurrent canker sores into three main types, depending on how big they are and where in your mouth you get them.

Minor canker sores
Most people get minor canker sores. These are round or oval, and usually less than one-fifth of an inch across. They tend to be grayish-white, with redness around them, and are usually on the inside of your lips or cheeks, or on the floor of your mouth. People usually get one to five sores at a time.
 
 
 
 
 
Source:
McBride DR.
Management of aphthous ulcers.
American Family Physician. 2000; 62: 49-54, 160.
 
 
 
 
 
2

Major canker sores
Major canker sores are less common than minor canker sores, and they are oval and larger. They may be around one-half to one-and-a-quarter inches across. They often happen on your lips or toward the back of the roof of your mouth (the soft palate), but they can be anywhere in your mouth. People usually get 1 to 10 sores at a time.
 
 
 
 
 
Source:
Porter SR, Scully C, Pedersen A.
Recurrent aphthous stomatitis.
Critical Reviews in Oral Biology and Medicine. 1998; 9: 306-321.
 
 
 
 
 
1

Herpetiform sores
Some people get lots of small, painful sores called herpetiform sores. These sores can occur anywhere in your mouth. You may have as many as 100 at a time, each measuring about one-eighth of an inch across. Some join together to form large, irregularly shaped sores.
 
 
 
 
 
Source:
Porter SR, Scully C, Pedersen A.
Recurrent aphthous stomatitis.
Critical Reviews in Oral Biology and Medicine. 1998; 9: 306-321.
 
 
 
 
 
1

Sources for the information on this page:
  1. Porter SR, Scully C, Pedersen A.Recurrent aphthous stomatitis.Critical Reviews in Oral Biology and Medicine. 1998; 9: 306-321.
  2. McBride DR.Management of aphthous ulcers.American Family Physician. 2000; 62: 49-54, 160.
This information was last updated on May 11, 2009
BMJ Group
This information is for educational use only, and is not a substitute for prompt professional medical advice. Readers should always consult a physician or other professional for advice and treatment.
© BMJ Publishing Group Limited 2009. All rights reserved.
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