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Aphthous Mouth Ulcers

  1. What are aphthous ulcers?
  2. Symptoms
  3. Causes
  4. Diagnosis
  5. Complications
  6. Treatment
  7. Prevention
  8. Prognosis
  9. FAQ

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. In most instances, aphthous ulcers are recurrent – a condition known as recurrent aphthous stomatitis (RAS) – with each episode 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.

Good to know: Aphthous ulcers are the most common type of mouth ulcer, but they are not the only kind of mouth ulcers.

There are three main types:[3]

Minor aphthous ulcers

These are the most common variety. They are small in size – usually less than 5 mm in diameter – and can form as a single ulcer or in a cluster. They typically do not cause much pain.

Major aphthous ulcers

These are less common, are generally 5 mm or larger and form singularly or in a pair. They can be painful, especially when eating or drinking, and last anywhere between two weeks and a number of months.

Herpetiform ulcers

These can 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. Once the ulceration occurs, localized pain of various degrees is often present.

What do aphthous mouth ulcers look like?

The ulcers (aphthae, canker sores or mouth sores) 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.

Good to know: In severe cases, aphthous ulcers can result in swelling of the lymph nodes, fever and physical fatigue or lethargy.[4] These cases, however, are extremely rare, and the swelling of the lymph nodes is therefore unlikely to be a first sign of aphthous ulcers. If you are concerned that you may have aphthous mouth ulcers, you can do a free symptom check with Ada at any time.

Causes of aphthous ulcers

The precise cause or causes of aphthous ulcers (canker sores) 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. 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.

Possible triggers of aphthous ulcers include:[5]

  • Emotional stress
  • Minor injury to the inside of the mouth, for example from cuts, burns or bites while eating, dental work, hard brushing or ill-fitting dentures
  • Familial tendency
  • Sodium lauryl sulfate – an active ingredient in some toothpastes and mouthwashes; this compound is 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 and/or minerals including zinc, B-12, folate and iron that may present with anemia
  • An allergic reaction to oral bacteria
  • Using, as well as quitting, the use of tobacco products
  • Hormonal changes associated with pregnancy
  • Having a weakened immune system, due to certain chronic conditions (Immunodeficiency)

Stress is a common cause of mouth ulcers. Although stress does not directly cause mouth ulcers, it does increase the chances of developing them and can affect their healing process.[6][7] Mouth ulcers can also cause stress by affecting how and what the affected person can eat and drink.

Good to know: Dentists are able to advise on ways to reduce the risk of developing aphthous mouth ulcers, for example recommending toothpastes and mouthwashes that do not contain sodium lauryl sulfate or advising on correct brushing equipment and technique to reduce the chance of injury to the inside of the mouth.

Some medications are also linked to the development of ulcers, however, they may not always cause the aphthous variety of ulcers. They include:[8][9]

  • Nicorandil, a drug used to treat angina pectoris, a heart condition
  • Ibuprofen and other anti-inflammatory medicines
  • Oral nicotine replacement therapy opposed to patch replacement therapy
  • 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 sign of several serious diseases, including:

The ulcers that are symptomatic of these disorders, however, are technically not aphthous but closely resemble aphthous ulcers and are therefore called aphthous-like ulceration.[10] People who experience recurrent outbreaks of ulcers or ulcers that are slow to heal, especially painful or accompanied by other symptoms should see a doctor as soon as possible. If you or someone you know has recurrent mouth ulcers or ulcers that do not heal, you can do a free symptom check with the Ada app at any time.

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.

A proper evaluation and diagnostic work-up of recurrent ulceration is important due to its links to other, more serious conditions such as celiac disease, inflammatory bowel diseases like Crohn’s disease or conditions causing a weakened immune system, such as HIV/AIDS. The diagnostic process may involve the ruling out of these conditions through blood tests or, less often, using a gastroscopy or colonoscopy, possibly also obtaining tissue samples.[11] The course the diagnostic work-up will take will depend on the doctor’s evaluation of the severity of an individual’s condition and the presence of any other symptoms.

Complications of aphthous ulcers

Although most mouth ulcers will clear up within two weeks, in very rare cases they may become infected with bacteria. This usually only happens in severe cases, where the ulcerated area is extensive.

In the case of a secondary bacterial infection, an antibiotic mouthwash and a means of managing the pain and discomfort may be prescribed. In some cases, oral antibiotics may also be needed (see the section below on treatment).[11]

Aphthous ulcers treatment

There is no cure for aphthous ulcers, aphthae or canker sores, but there are ways to manage the symptoms. In the majority of cases, the ulcers will disappear without treatment and avoiding hard or irritative foods, like e.g. pineapples, applying cold substances to the affected area and if needed using numbing preparations, like topical lidocaine or benzocaine will be enough to manage the pain.

When further treatment is required, there are several possible options, with the chosen route depending on a doctor’s judgement of how well each may work, based on the location and severity of the ulceration, and the affected person’s general health.[12]

Anti-inflammatory treatment

Over-the-counter, topical anti-inflammatory pastes applied directly to the problem area may be effective in managing the symptoms of aphthous ulcers (aphthae/canker sores), particularly of the minor variety. These pastes should be applied between two and four times per day, please follow the specific recommendations of your pharmacy or doctor.

Antiseptic and Antibiotic treatment for aphthous ulcers

The use of an antiseptic mouthwash e.g. containing chlorhexidine, twice per day or as per your doctor’s recommendations can be part of a treatment regimen of aphthous ulcers.[13] In rare cases a doctor may prescribe topical or oral antibiotics, such as tetracycline or minocycline, which 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.[14]

Good to know: Antibiotic mouthwashes containing tetracycline should be avoided in children younger than eight years of age or even older, depending on your doctor’s recommendations, as they can cause the teeth to become discolored.

Other treatments for aphthous ulcers

Other treatments may include topical or, rarely, oral steroids, typically used when the ulcers are unresponsive to other treatment methods; silver nitrate;; other local anaesthetics/numbing agents; and nutritional supplements (containing folate, zinc or vitamin B-12, for example).[15]

Home remedies for aphthous ulcers

There are a number of popular home remedies for aphthous ulcers, including:[16]

  • Rinsing the mouth with salt water
  • Rinsing the mouth with a solution of baking soda/sodium bicarbonate and water
  • Application of milk of magnesia to the ulcer after rinsing
  • Application of ice chips or cubes to the affected area to reduce swelling
  • Teething ointments containing local anaesthetic to manage pain and discomfort
  • Reducing stress
  • Avoiding hard foods or foods that may scratch the interior of the mouth

Nutritional supplements such as Vitamin B-12 capsules, Vitamin D capsules, folate tablets, or zinc tablets can also reduce the risk of developing canker sores.

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 in the individual person
  • Focussing on a healthy, balanced diet containing sufficient amounts of nutrients and vitamins
  • 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.

Ulcers that heal on their own within a few weeks are not an indication of oral cancer and are non-infectious. The ulcers, however, can be very painful and inconveniencing, especially if they are recurrent. Many people will find that they stop getting aphthous ulcers as they get older.

Good to know: If an ulcer or group of ulcers does not heal within three weeks, or lasts for longer than three weeks, the affected person should see a doctor as soon as possible for a proper diagnostic workup. In some cases, a persistent ulcer may indicate oral cancer.

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:[17][18]

  • Rinsing the mouth with a warm salt water/saline solution
  • Applying a small amount of milk of magnesia to the ulcer after rinsing
  • Sucking ice chips or cubes to reduce swelling
  • Teething ointments containing local anaesthetic
  • Avoiding hard foods or foods that may scratch the interior of the mouth or may cause irritation due to their acidic nature, like e.g. pineapple, lemons, oranges or tomatoes while the ulcer sore is present
  • Reducing stress

Q: Can I get aphthous ulcers (aphthae) in the genital region?
A: Yes, although oral aphthous ulcers are most common, aphthous ulcers 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.[19]

Q: Is it safe to have oral sex if the performing partner has mouth ulcers?
A: Mouth ulcers, because they are breaks in the skin inside the mouth, increase the risk of contracting sexually-transmitted infections such as herpes, gonorrhea, syphilis and chlamydia. This risk can be reduced if the receiving partner wears a condom or if a dental dam is used.[20] Good oral care and proper oral hygiene techniques can reduce the chances of developing some mouth ulcers or other breaks in the oral skin.

Q: Can smoking cause mouth ulcers?
A: Smoking can make mouth ulcers worse. The nicotine in cigarette smoke may reduce the amount of blood that flows to the mouth and gums, which may then slow down the healing process for any ulcers, cuts or scrapes inside the mouth.[21] Slow healing means that the painful period is prolonged and increases the chance of infection.

At the same time, it seems to be the case that smoking may reduce the chance of developing mouth ulcers, because it hardens the surface of the epithelial cells in the mouth.[22] However, smoking has many other harmful effects on the body and should be avoided.

Q: What is recurrent aphthous stomatitis (RAS)?
A: Recurrent aphthous stomatitis (RAS) is the name given to the condition of experiencing frequent bouts of aphthous mouth ulcers (aphthae). Although a single bout of aphthous stomatitis is possible, recurrent episodes are the norm.[23] Episodes 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. Behçet syndrome is by some experts considered an autoimmune disorder and by others an autoinflammatory disorder. Autoinflammatory disorders, like autoimmune disorders, are caused by an overactive immune system attacking the body’s tissues and causing inflammation.[24] 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 and additionally often present inflammation of part of the eye, called uveitis . Although mouth ulcers are a symptom of Behçet syndrome, mouth ulcers are common, and Behçet Syndrome is rare. Only very few people who experience mouth ulcers are affected by Behçet syndrome.[25]

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.[26]

Q: Can systemic lupus erythematosus cause mouth ulcers?
A: Mouth ulcers can affect about half of all people with systemic lupus erythematosus, an autoimmune disorder. Lupus-related ulcers are not aphthous mouth ulcers, and while they may be painful in some people, they are often not painful for many others. They commonly affect the roof of the mouth, but can also appear on the gums, lips and inside of the cheeks. They resemble aphthous mouth ulcers, being red sores, but may also be more varied in presentation, e.g. some may have a whitish, radiating halo.[27][28] People with lupus may also experience ulcers in the nose.[29]

Q: Can gastroesophageal reflux disease (GERD/GORD) cause mouth ulcers?
A: Gastroesophageal reflux disease, commonly known as acid reflux, is a condition in which gastric acid leaks up into the esophagus or, less likely, also into the oral cavity/mouth. If acid enters the mouth, GERD can cause the erosion of tooth enamel and an acidic taste. Mouth ulcers can develop. GERD may also cause a feeling of a sore throat and, in some cases, throat and esophageal inflammation and ulcers may develop. If GERD causes ulcers, they will more likely be found at the back of the mouth, the back of the tongue and the back of the throat, because of the path of the acid coming up from the stomach.[30]

Q: Can chemotherapy cause mouth ulcers?
A: Yes, chemotherapy often causes mouth ulcers. Chemotherapy can cause inflammation of the mucosal lining of the throat and mouth, leading to sores in the mouth.[31] Technically, if occurring in the mouth,the painful condition and ulcers caused by chemotherapy are known as stomatitis and may be related to mucositis, a condition which affects a larger area of the digestive tract’s mucosal lining.[32] For more information, read this resource on the side effects of chemotherapy.

Q: Can Hepatitis C cause mouth ulcers?
A: Yes, Hepatitis C or its treatment can sometimes cause mouth ulcers and other mouth conditions, such as tooth decay or a sensitive mouth by e.g. affecting saliva production and causing a dry mouth.[33] Because Hepatitis C is a complex condition, people who have Hepatitis C should consult their care teams regarding any concerns and before starting any treatment program.

Q: Are mouth ulcers a sign of cancer?
A: A mouth ulcer that does not clear up is sometimes a sign of oral cancer. However, very few mouth ulcers are a sign of cancer. Mouth ulcers associated with cancer are generally solitary rather than in clusters and appear without any apparent cause.[34] If a mouth ulcer persists longer than three weeks, causes symptoms the person can’t handle like not being able to eat or drink sufficiently due to pain and/or does not respond to treatment, the affected person should see a doctor.

Other symptoms of oral cancer may include:[35]

  • White or red patches on the gums, cheek lining or tonsils that are persistent or don’t get better
  • Persistent mouth pain
  • A lump in the cheek
  • Persistent throat pain
  • The sensation of something stuck in the throat
  • Difficulty swallowing, chewing, moving the jaw or moving the tongue

Q: Can aphthous mouth ulcers occur on the gums?
A: Yes, mouth ulcers can affect the gums. They may also affect the tongue, the inside of the cheeks, and the inside of the lips.

Q: What are the differences between cold sores and canker sores?
A: Cold sores, also known as herpes labialis, are caused by Herpes Simplex Virus 1 or 2. Aphthous mouth ulcers are not caused by viruses. Cold sores primarily affect the corners of the mouth, the lips, the nostrils and the philtrum, the area between the upper lip and the nose.

Cold sores are extremely contagious. Aphthous mouth ulcers typically affect the inside of the mouth, do not affect the nose and are not contagious.


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