Aphthous Mouth Ulcers

What are aphthous ulcers?

Aphthous mouth ulcers (aphthae) are a common variety of ulcer that form on the mucous membranes, typically in the oral cavity (mouth). Other names for aphthous ulcers include aphthous stomatitis and canker sores.[1]

Aphthous ulcers are generally round in shape and form in the soft areas of the mouth such as the inside of the lips, the cheeks or the underside of the tongue. They are benign, non-contagious and can occur as single ulcers or in clusters, but are in most instances recurrent – a disorder known as recurrent aphthous stomatitis (RAS) – with each outbreak normally lasting for between 7 and 10 days.[2] The cause of the condition is unclear and there is no cure, but treatment options are available to treat the pain the ulcers can cause.

Aphthous mouth ulcers affect around one in five people at least occasionally and most commonly begin to appear between the ages of 10 and 19. There are three main types:[3]

  • Minor aphthous ulcers are the most common variety. They are small in size – usually less than 5mm in diameter – and can form as a single ulcer or in a cluster. They are not typically very painful.
  • Major aphthous ulcers are less common, are generally 5mm or larger and form singularly or in a pair. They can be painful, especially when eating, and last anywhere between two weeks and a number of months.
  • Herpetiform ulcers occur when multiple pinpoint lesions fuse together and form large, irregularly shaped ulcers. Herpetiform ulcers are so called because of their similarity in appearance to herpes, however herpetiform ulceration is not caused by the herpes simplex virus.

Symptoms of aphthous ulcers

Aside from the ulcers (aphthae) themselves, the condition has very few symptoms. Before ulceration occurs, some individuals may begin to feel a burning or itching sensation inside the mouth which can be painful.

The ulcers (aphthae) are normally shallow and begin as pale yellow in colour, generally turning grey as the condition develops. They may be ringed with red or appear fully red when inflamed. Depending on where the ulcers are located, eating, drinking and talking may become uncomfortable. In severe cases, aphthous ulcers can result in fever, swelling of the lymph nodes and physical lethargy.[4] These cases, however, are extremely rare.

Causes of aphthous ulcers

The precise cause or causes of aphthous ulcers (aphthae) are unknown, however, it is thought that ulceration is brought about by one or a combination of external triggers. It may also be partly genetic, with 40 percent of people who experience ulcers having a family history of the condition.

Possible triggers of aphthous ulcers include:[5]

  • Stress
  • Minor injury to the inside of the mouth (from dental work or brushing, for example)
  • Familial tendency
  • Sodium lauryl sulfate – an active ingredient in some toothpastes and mouthwashes (not proven as a trigger, but is known to prolong the time needed for ulcers to heal)
  • Certain food and drinks, including coffee, chocolate, eggs and cheese, as well as acidic or spicy foods
  • A deficiency of certain vitamins including zinc, B-12, folate and iron
  • An allergic reaction to oral bacteria
  • Quitting smoking

Some medications are also linked to the development of ulcers, however, they may not always cause the aphthous variety of ulcers. They include:[6]

  • Nicorandil
  • Ibuprofen and other anti-inflammatory medicines
  • Medicines such as aspirin if left to dissolve in the mouth instead of being swallowed
  • Illegal drugs such as cocaine

Very rarely, recurrent ulceration can be a possible indicator of several serious diseases, including:

  • Crohn's disease
  • Celiac disease
  • Behcet’s disease
  • HIV/AIDS

The ulcers that are symptomatic of these disorders, however, may not be aphthous but closely resemble aphthous ulcers.[7] People who experience recurrent outbreaks of ulcers or ulcers that are slow to heal should see a doctor as soon as possible.

Diagnosing aphthous ulcers

In most cases, especially when the condition is not recurrent, diagnosis will be based around medical examination and an investigation of an individual’s medical history.

Diagnosis of recurrent ulceration is important due to its links to other, more serious conditions such as HIV, AIDS and celiac disease. The diagnostic process may involve the ruling out of these conditions through tissue, blood and viral testing, among other methods.[8] The course the diagnosis will take will depend on the doctor’s evaluation of the severity of an individual’s condition and the presence of any other symptoms.

Aphthous ulcers treatment

There is no cure for aphthous ulcers (aphthae), but there are ways to manage the symptoms. In the majority of cases, the ulcers will disappear without treatment and avoiding hard foods, numbing ointments and the application of cold substances to the affected area will be enough to manage the pain.

When treatment is required, there are several possible options, with the chosen route depending on a doctor’s judgement of the probable efficacy of each.[9]

Antibiotic treatment

Topical or systemic antibiotics, commonly tetracycline or minocycline, can be effective in treating ulcers. They are typically administered in mouthwash form, with the antibiotic being dissolved in water, swilled around the mouth and spat out. This may be necessary several times per day for a number of days.

Anti-inflammatory treatment

Anti-inflammatory pastes applied directly to the problem area may be effective in managing the symptoms of aphthous ulcers (aphthae), particularly of the minor variety. These pastes should be applied between two and four times per day.

Other treatments

Other treatments include oral steroids, typically used when the ulcers are unresponsive to other treatment methods; silver nitrate; debacterol; local anaesthetics; and nutritional supplements (containing folate, zinc or B-12, for example).[10]

Aphthous ulcers prevention

To lessen the likelihood of an ulcer outbreak, especially for those with a history of recurrent aphthous ulcers (aphthae), a number of measures can be taken.

  • Avoiding foods that may trigger ulceration
  • Maintaining good dental hygiene and using a soft toothbrush to avoid irritation
  • Reducing stress and getting plenty of sleep

Aphthous ulcers prognosis

Aphthous ulcers (aphthae) are generally non-serious and will go away without any particular treatment. They are also not an indication of oral cancer and are non-infectious. The ulcers, however, can be very painful and inconveniencing, especially when recurrent. Many people will find that they stop getting aphthous ulcers as they get older.

Aphthous ulcers FAQs

Q: Are there any home remedies for aphthous ulcers (aphthae)?
A: There are a number of popular home remedies for aphthous ulcers, including:[11]

  • Rinsing the mouth with salt water
  • Application of milk of magnesia
  • Application of ice chips or cubes
  • Teething ointments containing local anaesthetic
  • Reducing stress
  • Avoiding hard foods or foods that may scratch the interior of the mouth

Q: Can I get aphthous ulcers (aphthae) in the genital region?
A: Yes, although oral aphthous ulcers are most common, they may also appear in the genital region. This is most common in women, with the ulcers normally forming on the vulva or adjacent skin. The ulcers are in most cases of similar appearance to the oral version and may be similarly painful.[12]

Q: What is recurrent aphthous stomatitis (RAS)?
A: Recurrent aphthous stomatitis (RAS) is the name given to the condition of experiencing frequent outbreaks of aphthous mouth ulcers (aphthae). Although a single bout of aphthous stomatitis is possible, recurrent outbreaks are the norm.[13] Outbreaks of recurrent aphthous stomatitis (RAS) typically occur at intervals of between a few months to a few days and last for between 7 and 10 days at a time.

Q: What is the relationship between aphthous ulcers (aphthae) and Behçet syndrome? A: Behçet syndrome is characterized by inflammation in various areas of the body. One of Behçet syndrome’s distinguishing symptoms is the presence of aphthous ulceration in the oral cavity (mouth), as well as ulceration on others parts of the body, including the genitals. Although aphthous ulcers are a symptom of Behçet syndrome, not all individuals experiencing ulceration are affected by Behçet syndrome.[14]

Q: What is complex aphthosis?
A: Complex aphthosis is the given name to the condition of having almost constant oral aphthae or recurrent oral and genital aphthae without having Behçet syndrome. When complex aphthosis is suspected, medical attention should be sought for diagnosis and treatment.[15]


  1. DermNet New Zealand. “Aphthous ulcers.” January, 2016. Accessed July 13, 2017.

  2. Wikipedia. “Aphthous stomatitis.” June 20, 2017. Accessed July 13, 2017.

  3. Patient. “Mouth Ulcers.” August 31, 2016. Accessed July 13, 2017.

  4. WebMD. “Mouth ulcers: Symptoms, treatment and prevention.” Accessed July 13, 2017.

  5. Mayo Clinic. “Canker sore: Causes.” March 19, 2015. Accessed July 13, 2017.

  6. Patient. “Mouth ulcers: What are the causes of mouth ulcers?” August 31, 2016. Accessed July 13, 2017.

  7. BMJ Best Practice. “Aphthous ulcers: Clinical examination.” April 14, 2016. Accessed July 13, 2017.

  8. MSD Manual Professional Version. “Recurrent Aphthous Stomatitis.” September, 2016. Accessed July 13, 2017.

  9. American Family Physician. “Management of Aphthous Ulcers.” July 1, 2000. Accessed July 13, 2017.

  10. Mayo Clinic. “Canker sore: Treatments and drugs.” March 19, 2015. Accessed July 13, 2017.

  11. Mayo Clinic. “Canker sore: Lifestyle and home remedies.” March 19, 2015. Accessed July 13, 2017.

  12. DermNet New Zealand. “Non-sexually acquired genital ulceration.” 2010. Accessed July 13, 2017.

  13. NCBI. “Recurrent aphthous stomatitis.” September, 2011. Accessed April 25, 2018.

  14. MedicineNet. “Behcet’s Syndrome: Symptoms, Diet, and Treatment.” August 19, 2016. Accessed April 25, 2018.

  15. NCBI. “Complex aphthosis: a large case series with evaluation algorithm and therapeutic ladder from topicals to thalidomide.” March, 2005. Accessed April 25, 2018.