Mouth Ulcers

Mouth ulcers are usually pale or yellow painful sores with a red outer ring. These appear inside mouth, on the cheeks, lips and sometimes can also appear on the tongue. Usually a single ulcer inside mouth may be due to cheek or tongue biting, or damage caused by sharp teeth, aggressive brushing or poorly fitting dentures. These ulcers are known as ‘traumatic' ulcers. More than one ulcer inside mouth which are recurrent in nature are called Recurrent Aphthous Stomatitis (RAS).

These are different from cold sores and are not contagious. Cold sores appear on the outer lips or around the mouth and are caused by a virus. They often begin with a tingling, itching or burning sensation.



Aphthous stomatitis is a common ailment, with single or multiple ulcerations of the oral mucosa; usually self-limiting, painful, or recurrent.

It affects approximately 20% of the general population and it is slightly more common in girls and women. Typical age of onset is in childhood or early adulthood, becoming less common with advancing age.


 Aphthous ulcers present as well-circumscribed lesions with central necrotic region of gray, fibrinous exudate surrounded by an erythematous halo on the non-keratinised oral mucosa. Pain severity depends on the type of ulcer. Typical locations of ulcers include the buccal (cheek) and labial (lip) mucosa, the floor of the mouth, the ventral surface of the tongue, and the soft palate.


Aphthous ulcers are idiopathic (exact cause is not clear) and multifactorial, but likely involves activation of the cell-mediated immune system.

These factors may include:

  • Local trauma due to badly fitting dentures, braces, rough fillings or a sharp tooth, cuts or burns while eating or drinking hard food or hot drinks
  • Emotional or physiologic stress, hormonal states (menstruation or pregnancy)
  • Food hypersensitivity (such as cinnamon, cheese, citrus, figs or pineapple), sensitivity to sodium lauryl sulfate and certain medications (NSAIDs, beta-blockers or nicorandil).
  • Many cases are related to iron, folic acid, vitamin B6 or B12 deficiency. 
  • Family history, immunological, and microbial factors are important in the onset of recurrent aphthous ulcerations.
  • Systemic illness such as malabsorption, enteropathy, coeliac disease/inflammatory bowel disease, vasculitis (e.g., Behcet’s syndrome), reactive arthritis (e.g., Reiter’s syndrome), and HIV/AIDS.
  • Aphthous stomatitis is more prevalent in non-smokers and smokers who quit smoking.
  • Less common in individuals with good oral hygiene practices.


Based on the clinical examination and on the patient’s medical history, a diagnosis of aphthous ulcers is determined.


  • Keep your mouth as clean as possible



Use a soft toothbrush

Do not brush vigorously

Drink cool drinks through a straw

Do not eat very spicy, salty or acidic food, rough or crunchy food,

Eat soft food items

Do not drink very hot or acidic drinks, such as fruit juice

Eat a healthy, balanced diet rich in vitamins A, C and E

Do not use toothpaste containing sodium lauryl sulphate

Regular Dental visits

Do not use chewing gum


Types of Aphthous ulcers

Minor Aphthous Ulcers: Most common, less than 1 cm in diameter and can sometimes occur in clusters. Heal typically within 7-14 days. 

Major Aphthous Ulcers: Large (often 2-3 cm in diameter), more severe and can take many weeks or months to heal. These ulcers may have irregular raised borders which sometimes heal with scarring.

Herpetiform Aphthous Ulcers: Less common, 1 to 2 mm in diameter in clusters of 10 to 100 in groups or throughout the mouth, which usually heal within a few weeks.

However, last two varieties are very rare.

  • If an ulcer lasts more than 3 weeks you should always ask dentist or doctor for advice.
  • There may be ulcers in other parts of the body such as eyes or genital area. It is important to inform dentist about this.
  • The ulcers caused by mouth cancer can first appear on or under the tongue, but may occasionally appear somewhere else in the mouth. They are usually single and last a long time without any obvious nearby cause (for example a sharp tooth). Mouth cancer is usually linked to heavy smoking and drinking. Doing both together greatly increases the risk.



The treatment to speed up healing, prevention of recurrent episodes and to reduce pain, depends on the cause of the ulcers:

  • Sometimes only a sharp tooth needs to be smoothed down or a denture adjusted.
  • Topical analgesic pastes to reduce ulcer pain, apply as needed.
  • Protective bio adhesives
  • Antimicrobials
  • Topical corticosteroid agents


Patients who suffer from frequent, recurrent episodes of aphthous ulcers should be referred to either an oral medicine/oral pathology specialist or their physician to rule out any possible systemic association, other infections (Herpes simplex virus), chronic mucocutaneous diseases (e.g., lichen planus, pemphigus, pemphigoid), thrush (also called Candidiasis or moniliasis-a fungal infection), cancer.




  • PUBLISHED DATE : Apr 16, 2019
  • CREATED / VALIDATED BY : Dr Rida Ziaul
  • LAST UPDATED ON : Apr 16, 2019


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The content on this page has been supervised by the Nodal Officer, Project Director and Assistant Director (Medical) of Centre for Health Informatics. Relevant references are cited on each page.