Painful Ulcers in my Mouth

Many young people come to us with a complaint of painful ulcers in their mouth. While there are many causes to ulcers in the oral cavity, one of the most common causes is what we call “Canker Sores” (in medical jargon they are called aphthae or minor aphthous stomatitis).
Canker sores are very common: over half of people experience them in their lifetime. In about a third of the people with aphtha there is a family history – meaning at least one other person in the family experiences ulcers. These ulcers are slightly more common in females and in people 10-40 years of age. Canker sores are different from cold sores, the latter being caused by an infection with the herpes simplex virus.
The causes of canker sores are not entirely clear, but they are not infectious, contagious, or sexually transmitted. There are, however, a few factors associated with the appearance of these ulcers: stress; cessation of smoking, trauma (biting); endocrine factors (period, uncommon in pregnancy); food allergies (such as cow’s milk); and exposure to sodium lauryl sulphate in oral healthcare products.
Before you see these sores, you may feel unpleasant sensations such as burning, itching, or stinging. These sensations could precede the appearance of any lesion by hours. Canker sores are painful and the pain is worsened by physical contact, especially with certain foods and drinks (e.g., acidic foods or drinks).

How do these sores look like?

Canker sores are small, round or ovoid ulcers (opening in the lining of the mouth), and are generally 2-4 mm in diameter. They can be linear when in the inner side of the check. At first they are yellowish but may become grayish when starting to heal. The ulcers are surrounded by a reddish halo and some swelling.
Canker sores are commonly found on the inner side of the lips, cheeks, the floor of the mouth, sulci (that’s the grove between your check and your gum), or lower side of the tongue. Rarely the sores appear on the palate or the upper side tongue. These sores may occur in groups of a few ulcers (i.e. 2-6) at a time.


Canker sores generally heal in 7-10 days but may recur at intervals of 1-4 months. They leave little or no evidence of scarring. No treatment is required but you may use topical corticosteroids or swallow vitamin B12 if they are very painful. Topical corticosteroids may ease the pain but do not cure and require a prescription from your dentist.

When to Seek Medical attention?

Aphthous-like ulcers may appear in many diseases and states. For example, deficiencies of iron, folate, vitamin B-12 and as well in diseases such as Celiac, Crohns or Behçet syndrome. They also appear in immunodeficiencies such as human immunodeficiency virus (HIV) infection, or malignancies. Ulcers can also be caused by certain drugs, such as NSAIDS (aspirin).

If you suspect you have any systemic disease, please consult your dentist or your family physician.


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