Why do we get canker sores?

Canker sores, not to be mistaken with cold sores, are small sores that appear on the inside of the mouth or at the bottom of the gums. These sores are actually pretty common, affecting about 3 million people in the United States per year.  Although often mistaken for cold sores because of their similar appearance, canker sores are very different in that the sores, or blisters do not occur on the lips and are not contagious like in cold sores.  It is important to remember that cold sores are a result of herpes virus infection, while the causes of canker sores are unclear and variable.


Although the precise cause of these bothersome mouth sores is unclear, there are certain triggers that can contribute to their appearance.  Some of the most common triggers are listed here:

·         A minor injury in the mouth

·         Reaction to certain foods that may cause sensitivity in the mouth

·         Vitamin deficiency (specifically in B-12, zinc, folate or iron)

·         Reaction to bacteria in the mouth (like H. pylori)

·         Emotional stress

·         Hormonal shifts (females)

As you can see, the causes are pretty routine, like any cut, scrape or injury you might incur on the skin.  Although there are certain triggers for canker sores, they can although be seen in higher frequency in association with particular illnesses.  The following are a few conditions that are likely to cause the sores:

·         Celiac disease

·         Inflammatory bowel diseases (Crohn's / ulcerative colitis)

·         Behcet's disease (inflammatory disorder)

·         HIV/AIDS

·         Autoimmune disorders


These sores can be both painful and bothersome, making it difficult for those who have them to eat and talk depending on the severity.  Luckily, these sores do not typically last for more than a week or two at a time.  Treatments include mouth rinses, pastes, and medications that focus on numbing the area to mitigate the painful symptoms.  If these sores do not go away in a couple of weeks, it might be time to consult a doctor.  Because most canker sores are rather minor, a dentist or general practitioner should be consulted if your pain or the size of the sore is not minor.  If the sore does not seem to be healing or getting better, further treatment could be needed. For some people, the frequency of the sores might be the issue, and if they are occurring regularly, you may want to figure out what the cause is.  Repeated injury to the area or irregular brushing could be the cause, or perhaps some type of underlying illness.  Contact your doctor if you experience:

·         Unusually large canker sores

·         Recurring sores

·         Frequent outbreaks

·         Persistent sores (over 2 weeks)

·         Sores that extend into the lips

·         Uncontrollable pain

·         Extreme difficulty eating or drinking

·         High fever along with canker sores