ABC Medical Center > Canker sores

What is Canker sores?

21:53 - 4 May , 2021


It is a whitish or yellowish ulcerative lesion in the mouth that is usually surrounded by a reddish outline, which is not contagious nor is it some type of cancer.

Being exposed sores, canker sores are painful and annoying in the area where they are located, since chewing or contact with various foods and drinks can cause intense burning.

The areas where they usually appear are the tongue, the palate, the gums, and the inner part of the lips and cheeks.

It is considered that most of the time, canker sores are the product of a viral infection or arise as a result of having a weakened immune system, although sometimes they can be due to hereditary issues, and in others, it is not possible to identify their origin. Other possible causes are:

  • Damage to the oral tissue caused by dental treatments.
  • Brushing your teeth too hard.
  • Accidental bites to the cheeks or tongue.
  • Stress episodes.
  • Vitamin B12 deficiency.
  • Iron deficiency.
  • Folic acid deficiency.
  • Hormonal alterations.
  • Allergic reactions to certain foods.

Although people of any age and sex can have canker sores, its incidence is higher in women.

Signs and symptoms Canker sores

  • Bumps that cause pain that change until they become ulcerative lesions.
  • Canker sores are whitish or yellowish surrounded by a reddish outline.
  • Canker sores are usually small (one centimeter or less).
  • They have a grayish tone when they are disappearing.
  • High fever.
  • General discomfort.
  • Swollen lymph nodes.

Pain considerably decreases after the first week, although it can take up to three weeks for the canker sores to disappear completely.

Diagnosis and treatment Canker sores

Once your doctor analyzes your symptoms and clinical history, they will perform an oral examination to identify the type of lesions you have and determine if they are canker sores.

If the diagnosis is confirmed and despite treatment the canker sores become chronic or recurrent, it will be necessary to perform a biopsy and other tests to find out if there is an underlying disease that is the direct cause of its appearance, such as herpes, erythema, lichen planus, or any drugs or foods allergies.

Most of the time, no treatment is required for canker sores as they heal on their own, you simply need to avoid irritating foods and drinks, regularly rinse with salt water, and maintain proper oral hygiene.

When there are many or very large ulcers or they cause severe pain, you will be prescribed mouthwashes and corticosteroids.

At ABC Medical Center’s Internal Medicine Department, we offer health care services with the highest quality and safety, from the prevention, diagnosis, timely treatment, and monitoring of infectious, respiratory, endocrinological, dermatological, rheumatic, nephrological, gastrointestinal, and hematological pathologies of both chronic-degenerative diseases and acute conditions, through a comprehensive and multidisciplinary model.


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