Mouth Sores

Mouth sores can be annoying, debilitating, painful and unsightly, but they can also be signs of disease or other underlying health problems. Any mouth sore that lasts a week or longer should be examined by a dentist. Two of the more common mouth sores are:


Canker sores, also known as recurrent aphthous ulcers, are small ulcers which typically have a gray or white center with a red border. Canker sores are found only inside the mouth and are not contagious, but can be extremely painful. Canker sores can occur singly or in clusters and often recur. They can be brought on by stress, fatigue, certain foods (usually spicy or acidic), allergies or trauma. Intestinal problems, such as Crohn's disease or ulcerative colitis, can make one more susceptible.

Canker sores typically heal in 7-10 days. However, in some circumstances, one out-break can give rise to successive outbreaks. Over-the-counter rinses and topical anesthetics can provide relief for discomfort. Antibiotics and oral ointments, such as Orobase, can reduce the chance of secondary infection.


Fever blisters, also known as "cold sores" or Herpes Simplex, are clusters of fluid-filled blisters which occur outside the mouth. Typically erupting on or around the lips, nostrils or chin, fever blisters are painful and unsightly. They are definitely contagious. The initial infection (primary herpes), which often occurs before adulthood, is frequently mistaken for a cold or the flu, and can cause the painful eruption of lesions throughout the mouth.

Once infected, a person will be prone to additional outbreaks. The virus stays in the body, typically residing in nerve endings in a specific, affected area. Subsequent eruptions tend to recur in that same area, and are triggered by stress, fatigue, fever, sunburn or trauma to the area.

Fever blisters generally heal by themselves in 1-2 weeks. Over-the-counter topical anesthetics can provide relief for discomfort. Antiviral drugs can be prescribed to lessen the duration and severity of larger eruptions.

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If you have any questions about canker sores or fever blisters, Dr. Mahlin would be happy to discuss them with you.

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Scott Mahlin, DDS, FAGD, FICOI and Clarkson Dental Group, serving West St. Louis County area in Chesterfield, MO Disclaimer: This website is provided for information and education purposes only.  No doctor/patient relationship is established by your use of this website.  No dentistry diagnosis or treatment is being provided.  The information contained here should be used in consultation with a dentist of your choice.  No guarantees or warranties are made regarding any of the information contained within the website.  This website is not intended to offer specific medical or dental advice to anyone.  Further, this web site and Dr. Scott Mahlin, DDS, FAGD, FICOI take no responsibility for web sites hyperlinked to this site and such hyperlinking does not imply any relationships or endorsements. Please contact us with any concerns.


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