Mouth ulcers: symptoms and causes of aphthous stomatitis

mouth ulcers causes and symptoms

It's not uncommon for small ulcers to appear on the inner mucous membranes of the mouth. These small, superficial ulcers are not contagious, but they can cause discomfort when you eat or speak. What causes canker sores and what are the most common symptoms? In most cases, they disappear on their own within a week. If they persist or cause you pain, consult your GP or health care professional. dentist in Lausanne, Fribourg or Aigle

Symptoms of common mouth ulcers

Canker sores appear inside the oral cavity as small, round or oval ulcers. The center is whitish or yellowish, with a red outline. You usually feel a burning or pulling sensation 24 to 48 hours before they appear. In more scientific language, aphthous stomatitis is the term used to describe recurrent outbreaks.

Here are the different types of mouth ulcers, with the main symptoms that help to distinguish them.

Minor mouth ulcers

This is the most common form of mouth ulcer: small (2 mm to 1 cm in diameter), oval-shaped, healing naturally and without scarring after 7 to 17 days.

Major mouth ulcers

This type of canker sore is less frequent: large size (over 1 cm in diameter), irregular contour, pain, long healing time (6 weeks), often leaving scars.

Herpetiform aphthae

This very rare type of mouth ulcer tends to develop in advanced age. It first appears as a group of 10 to 100 mouth ulcers with irregular contours. These eventually coalesce to form an ulcerated area, which disappears naturally after one or two weeks.

Mouth ulcers are uncomfortable and painful (for the first few days), but neither infectious nor contagious. They are completely harmless and pose no health risk. If you suffer from them, chewing often becomes difficult. 

In some patients, these ulcerations tend to recur. If they appear repeatedly, talk to your dentist. This may be the first sign of another, more serious condition, Behçet's syndrome.

The various factors that trigger canker sores

These ulcerations appear on gumsThe cause of these minor disorders varies widely from case to case. The origin of these minor disorders varies greatly from case to case. Here's a list of common causes of mouth ulcers: 

An injury to the mucous membranes

A small wound inside the mouth can potentially be a starting point for ulceration. The cause: poor fit of the appliance or the denturesa brushing teeth too vigorouslya cheek bite, a hard food that hurts the mucous membranes, oral surgery...

Ingesting certain foods

Diet also plays a role in the development of mouth ulcers in the oral cavity. Consumption of spices, dairy products, dried fruit, nuts or pineapple causes ulceration in some people. Acidic foods, vinegar and alcohol also promote the development of mouth ulcers. Studies have also shown that their recurrence can be a sign of food allergy or sensitivity. 

Mineral and vitamin deficiencies

The repeated appearance of mouth ulcers is often a sign that you are suffering from dietary deficiencies. These are mainly deficiencies in iron, zinc, folic acid or certain B vitamins (B12, B1, B2 and B6).

Fatigue, stress or emotional shock

In some cases, mouth ulcers can be traced back to psychological factors. Stress, fatigue or emotional shock weaken the immune system. As a result, the body becomes more susceptible to the onset of mouth ailments. As a result, all immunodepressive illnesses, including AIDS, offer ideal breeding grounds.

Smoking cessation

Smokers who quit tobacco consumption can suffer from mouth ulcers. 


The menstrual cycle brings its share of hormonal changes. Some women are prone to mouth ulcers during their period. 

Diseases or genetic factors

Recurrent mouth ulcers can be caused by disease. This is particularly true of celiac disease and Crohn's disease. It would appear that some people are genetically predisposed to recurrent canker sores.


Prolonged corticosteroid treatment, non-steroidal anti-inflammatory drugs (including ibuprofen), beta-blockers (including propranolol) and alendronate (for osteoporosis) can cause mouth ulcers.

When should you see a dentist for aphthous stomatitis?

We recommend that you make an appointment at a dental practice in Lausanne or Fribourg in the following cases:

  • An abnormally large ulceration
  • Recurring mouth ulcers
  • An ulceration that develops towards the lips
  • Mouth ulcers that persist for more than 2 weeks
  • Pain that prevents you from living normally
  • Mouth ulcers that make it difficult to eat or drink
  • Aphthous stomatitis accompanied by high fever
  • Dental appliances or prostheses that hurt your mucous membranes

The HELVIDENT team welcomes you to its three dental clinics in Fribourg, Lausanne and Aigle. Please do not hesitate to contact us to make an appointment with one of our dentists for cure your mouth ulcers.