Causes of Mouth Ulcers (Mouth Sores)

Mouth sores are shallow, painful ulcers in the inner part of the mouth, tongue or inner lip. It usually does not affect the gum or hard palate (upper roof of the mouth) except in certain cases. A mouth ulcer is usually not a serious condition and usually resolves within 10 days. However chronic mouth sores can persist for several weeks to months.

The condition of mouth ulcers is referred to as aphthous stomatitis. Mouth ulcers may also be called mouth sores or oral canker sores. Oral canker sores should not be confused with cold sores on the skin around the mouth.

Signs & Symptoms of Mouth Ulcers

Most mouth ulcers appear as red patches surrounded by a raised border. Eating or drinking may cause discomfort or pain at the area of the mouth sore.  In severe cases of multiple mouth sores throughout the mouth, movement when talking can also cause pain and discomfort and affect normal movements of the mouth.

Mouth ulcers are often preceded by blisters in the mouth. These are tiny, fluid or blood filled vesicles on the inner mouth and may also occur on the hard palate or gum. Mouth ulcers should not be confused with oral thrush (candida) which is caused by an yeast infection starting on the tongue and then spreading to the sides of the mouth cavity (cheeks).  Oral thrush causes white plaques on the tongue and is common in HIV/AIDS sufferers and patients suffering with severe chronic conditions.

Causes of Mouth Ulcers

The exact cause of mouth ulcers may not always be identified and can occur spontaneously. Usually these sores in the mouth resolve quite rapidly and do not recur. Some known causes and predisposing conditions include :

  • Physical injury to the mouth by chipped or jagged teeth, hard and sharp foodstuffs and extreme hot foods and drinks.
  • Chemical irritation or damage by toxic substances, allergic reactions to spices, certain dental care products and other irritants.
  • Vitamin and mineral deficiencies like low vitamin B12, folate, iron and vitamin C.
  • Excessive dryness of the mouth caused by smoking, mouth breathing (sinusistis and hay fever sufferers), diabetes mellitus (sugar diabetes) and certain chronic medication.
  • Infections by a number of bacteria, viruses, fungi and protozoa.
  • Chronic conditions like diabetes, many autoimmune conditions, bowel disorders like Crohn’s disease, ulcerative colitis or Behcet’s syndrome.
  • Menstruation and pregnancy due to fluctuating hormone levels.
  • Impaired immune functioning as in HIV/AIDS.

Treatment of Mouth Sores

In most cases, mouth sores will heal completely within a few days without treatment. However persistent mouth ulcers may require treatment or it will not resolve spontaneously. Treatment of mouth ulcers should focus on the cause or condition causing the sores. Other measures may include :

  • Oral antimicrobial solutions used as a mouth wash or held in the mouth for a few minutes.
  • Oral antibiotics may be necessary in cases where recurrent bacterial infections prevent the mouth ulcers from healing.
  • Corticosteroid oral solutions or tablets may be necessary in severe cases that are not responding to other medication.