Contrary to popular belief, canker sores are not the outcome of bacterial or viral infections and are not at all contagious. Different from cold sores that are caused by the herpes virus, canker sores are actually just a small ulcer within the protective lining of the mouth. Canker sores are auto-immune, meaning the body is attacking itself when they arise. Canker sores can be thought of as a blister but without the outer dome. Despite many efforts by doctors and dental professionals, the exact causes of canker sores are still unknown and unclear. Research points to a number of different potential causes that could trigger the outbreak.

You will recognize a canker sore developing by a burning or tingling sensation right before the sore appears. Then, you will notice the sore looking round, gray or white, and with a red border. The following are some of the most common causes of canker sores:

  • Stress
  • Mouth injury
  • Menstrual cycle
  • Viral infection
  • Immune system problem
  • Hormonal change
  • Vitamin deficiency
  • Food allergy

In addition, some fruits and vegetables like tomatoes, strawberries, oranges, figs, lemons, apples, and pineapples can cause canker sores due their acidity or citrus nature. Canker sores typically go away in a week or two without any treatment and the pain they cause usually only lasts a couple of days. For more serious canker sores, a dentist may prescribe some type of antimicrobial rinse or an ointment to reduce the irritation and pain. When in doubt, be sure to contact a healthcare professionals if the pain last for more than a few days.