Canker Sores

Canker sores - What are canker sores?

Canker sores are essentially sores in the mouth that cause a great deal of pain and discomfort. They are also called oral sores or aphthous ulcers.

These sores are not cancerous and they are different from cold sores or fever blisters or sores caused by herpes virus. (1-6)

Symptoms of canker sores

There is a small ulcer or a sore within the mouth usually found:

  • in the insides of the cheeks
  • base of the gums
  • over the palate or roof of the mouth
  • over the tongue
  • within the throat

There is a disruption in the mucus layer in the mouth. The sore is a small white or yellow in color and has a swollen, red area around it.

The condition may occur suddenly or may develop over a period of days. The lesions may be confined to a small area within the mouth or may be more widespread.

The condition is usually benign and resolves on its own. It does not usually cause a serious problem but may cause severe pain and discomfort.

There may be fever and swollen lymph nodes as well. Canker sores are the commonest form of mouth ulcers.

How long do canker sores last?

The pain over the sore is most intense the initial 2 to 3 days making it difficult to eat or speak.

The pain usually goes away in a week to 10 days. It can take 1 to 3 weeks for complete healing of the sore.

Triggers of canker sores

There are several triggers that lead to canker sores. For example, a wound or injury to the mouth may lead to a bacterial infection causing sores in the mouth. The wound may be caused by biting of the insides of the cheeks, lips or tongue inadvertently.

Those with a weak immune system are also at risk of canker sores.

Other triggers of canker sores include:

  • hormone fluctuations
  • allergic reactions
  • emotional stress
  • vitamin deficiencies
  • menstrual periods
  • tobacco use
  • smoking
  • alcohol consumption

They may occur with viral infections but in many cases no exact cause is determined.

Who is at risk of canker sores?

Women are more likely to get these sores than men. The cause of this is unknown. Canker sores may run in families but are not spread on contact.

Prevention of canker sores

Canker sore prevention involves good dental hygiene. Regular brushing of teeth, flossing and visits to the dentist for check-ups help prevent these oral sores.

For example, a sharp edge of a tooth that is causing regular injury and recurrent sores may be treated if detected on regular dental check-ups.

Causes of canker sores

A wide range of factors may trigger mouth canker sores. The exact cause may often be unknown and thus may not always be avoided.

What are canker sores?

Canker sores are small and painful mouth sores. These are not cancerous and usually resolve without treatment.

These sores are the commonest cause of mouth ulcers. It has been estimated that somewhere between 20% and 60% of the population have had canker sores at one time or another.

Common triggers and causes of canker sores

Common triggers and causes of canker sores include (1-6):

  • Unknown causes – in substantial number of cases the cause of canker sores is not known.
  • A wound within the mouth. This could be due to inadvertent biting of the lips, insides of cheeks or tongue during chewing or injury due to sharp foods or dentures or even sharp edges of teeth.
  • Weak immune system usually triggers canker sores. Those with a weak immunity do not have the strength and means to fight against the bacterial infections within the mouth after minor injuries and this leads to canker sores.

Some diseases of the immunity like Behcet’s disease or Kawasaki’s disease also cause increased risk of canker sores in the mouth.

  • Hormonal fluctuations lead to a risk of canker sores. Women with premenstrual tension and during their menstrual periods when there are hormonal changes are more at risk of canker sores. The causes are unknown.
  • Those with certain food allergies are at risk of canker sores. Due to allergies they may develop sores within their mouths that turn and develop into canker sores.

Some foods like spicy preparations, chocolates citrus, acid foods (vinegar, pickles) and excessive salted nuts or potato chips may lead to tiny mucosal injuries. These cause canker sores.

  • Chemical injuries to the inside linings of the mouth may occur due to excessive tobacco use, smoking and alcoholism. This type of injury also results from injury of the mucosal lining due to taking excessively hot beverages or foods.
  • Canker sores may occur due to viral infections.
  • Recent dental work, aggressive brushing or cleaning of the teeth may lead to injuries and susceptibility to canker sores.
  • Emotional stress such as examinations, anxiety, depression and other emotional upheavals may lead to an increased risk of canker sores. Physical stress may also lead to an increased propensity for canker sores.
  • Some studies have indicated that lack of certain vitamins and minerals in the diet like Vitamin B 12, iron and folic acid may lead to canker sores.
  • Women are more likely to get canker sores than men
  • In some individuals the risk of canker sores are inherited. These sores however do not spread from person to person by contact.

Symptoms of canker sores

Canker sores are small mouth ulcers that can cause great deal of pain and discomfort. They are not cancerous and are usually associated with trauma or injury to the inner linings of the mouth called the mucosa that gets infected by bacterial invading the breach in the protective layers.

What is a canker sore?

A typical canker sore is a small ulcer within the mouth. It is commonly noted at the base of the gums, the insides of the cheeks, the soft palate (back part of the roof of the mouth), over the tongue, inside the throat or on the insides of the lips.

What do the lesions look like?

The lesions appear white or yellowish in color and have a cheesy base that signifies the ulcer. There is a raised red edge that may be swollen.

There may be a single localized sore or numerous sores in the mouth.

How many canker sores occur together?

Commonly 2 to 3 canker sores appear at one instance. However, in some individuals there may be 10 to 15 ulcers at a particular attack.

How do canker sores begin?

The sores begin as red spots or bump and go on to develop into an open ulcer. The canker sores are preceded by tingling or burning for a day before they appear.

How big are canker sores?

The sore is usually a small one with less than 1/8 to ¼ inches in diameter. Those that are major ulcers may be 1/2 inches in diameter.

Sores are most often roughly oval in shape. The whole lesion is excruciatingly painful especially the initial 7 to 10 days making it difficult to eat or speak.

Healing of canker sores

The sore may turn grey just as it begins to heal. Some patients may have other symptoms like fever, general feeling of unwell and swollen lymph nodes.

The pain recedes in a week or 10 days and the ulcer takes around 1 to 3 weeks to heal completely. Large ulcers can take longer to heal.

Inheritance of canker sores

Around 40% of the patients with canker sores have someone in their family with the condition as this condition may be inherited. Canker sores however do not spread on contact and are not contagious.

Recurrence of canker sores

In some individuals the sores may recur frequently. Attacks may vary from one sore every 2 or 3 months or even continuous presence of canker sores at various locations within the mouth.

Recurrence at the same area may indicate a repeated trauma with an ill-fitting denture or with a sharp edge of a tooth.

Therapy for canker sores

In most cases the canker sores heal without any therapy. However, since they make intake of food and nutrition difficult, these factors need to be kept in mind. Especially in children with canker sores nutritional maintenance is important.

Canker sores and more serious pathologies

Duration of the canker sore is important as longer lasting sores may be indicative of more serious pathologies like oral cancers. History of smoking, chewing tobacco and alcohol use is also important in these cases.

In addition, if there are features of fatigue, abdominal pain, fever and loss of body weight and appetite over a period of time a more serious diagnosis is considered and the patient is evaluated. Eye discomfort, rashes or sores over other parts of the body also indicate other underlying pathologies.

Three types of canker sore

Canker sores may be of three basic types:

  • Minor Aphthous Stomatitis

This is seen in more than 80% cases of canker sores. The sores are less than a diameter in size. These sores take around a week to heal completely. There is no resultant scarring after the sores have healed.

  • Major Aphthous Stomatitis

This is a more serious form of canker sores. It affects around 15% of all sufferers. These sores often last two weeks or more. They are usually over 1cm in diameter. They can be extremely painful and may leave behind scars after healing.

  • Herpetiform Aphthous Stomatitis

This occurs in less than 5% of the sufferers with canker sores. Sufferers usually get very small ulcers that may be less than a millimetre in diameters in clusters that merge to form larger ulcers. These take a week or so to heal completely. (1-7)

Diagnosis of canker sores

Canker sores are the commonest cause of mouth ulcers. They are usually benign and resolve on their own in 1 to 3 weeks.

However, these sores are extremely painful and may lead to severe discomfort. There may be difficulty in eating and speaking in severe cases of canker sores.

The sores are commonly diagnosed clinically by examining them. (1-5)

Classification of canker sores

Canker sores on the basis of their appearance and features are classified as (2):

  • Minor Aphthae

They are seen in 80% cases of the canker sores. Patients provide a history of tingling or burning 1 to 2 days before the sores appear.

The sores themselves are 2-8 mm diameter and are shallow, greyish yellow and may occur in clusters of less than five sores. The sores are painful for 3 to 4 days or so. In 10 to 14 days the sores heal without scars.

  • Major Aphthae

These occur in 10% cases of canker sores. The sores appear irregular in shape and have raised borders. They may be 1 to 3 cm in diameter.

These ulcers may be recurrent and often leave scars in their wake after healing. Biopsy is recommended to rule out oral cancer called squamous cell cancer.

  • Herpetiform Aphthae

The name is a misnomer since this is not caused due to Herpes virus. There are large clusters of very small lesions (less than 3mm in diameter).

The clusters may contain 5-100 lesions that fuse to form larger, painful lesions. It takes around 10 to 14 days for these ulcers to heal.

Process of diagnosis

The process of diagnosis of canker sores involves taking a complete medical history, categorizing the level of pain and so forth. (1-5)

Complete medical history

Diagnosis is begun with a complete medical history. This is helpful in diagnosis of:

  • tobacco or alcohol use
  • food and other allergies
  • hormonal fluctuations
  • recent dental work
  • decreased or impaired immunity
  • history of oral sexual intercourse and herpes virus infections and other causes that may lead to increased propensity of canker sores

Categorizing the level of pain of canker sores

Most patients complain of varying severity of the discomfort due to the canker sores. These may be roughly categorized as mild, moderate, or severe.

Mild disease occurs seldom and is not severe or long lasting. Most cases belong to this category.

Presence of four or more canker sores per year is classified as moderate severity canker sores. Those that are more severe are classified as severe disease.

Examining the canker sores

Diagnosis is commonly made by looking at the canker sore. The sore has a typical appearance of a round or oval while cheesy or greyish base or the ulcer and raised red and swollen edges.

The doctor sits opposite the patient with a head lamp or an over head lamp to keep the hands free for examination. Lumps, swollen lymph nodes are noted to exclude other pathologies like cancers.

During the examination dentures are removes and the insides of the cheeks, gums, tongue (above and below the tongue), soft palate (back part of the roof of the mouth) and the throat is examined.

The location, size, color, bleeding, greyish plaque formation over the lesion are all noted. The throat is examined using a tongue depressor and asking the patient to say “aah”.

Palpating canker sores

Once located the doctor wears gloves to physically palpate the lesion or ulcer. This may be painful and is usually performed gently.

If the ulcer is fixed to the underlying muscles and tissue or if there is hardening of the ulcer base, it can be detected by palpation. This is indicative of a deeper and more serious problem like oral cancer.

Tests for other disorders

In patients with recurrent ulcers that tend to persist or recur frequently other disorders are suspected. Tests are conducted for disorders like erythema multiforme, drug allergies, infections with herpes virus, bullous lichen planus etc.

Long term ulcers may also indicate oral cancers. A biopsy may be undertaken in these patients.

This involves snipping off a small bit of tissue from the ulcer and its surrounding areas, staining it with appropriate dyes and examining the same under the microscope. Canker sores are not cancer and do not lead to cancer if they recur.