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Canker sores: What you should know

They are a common and well-known disorder in which canker sores appear in the mouth and are easily diagnosed.

Despite the fact that they can be extremely uncomfortable, they are rarely a reason for alarm.

Throughout this piece, we enquire as to whether there is anything that may be done to alleviate canker sores, as well as whether there are instances in which they necessitate medical assistance.

Important things to know about canker sores

Here are some important factors to remember about canker sores. More information and supporting documentation can be found in the main article.

  • Despite the fact that there are identified risk factors, the exact cause of canker sores is still unknown.
  • The vast majority of canker sores do not necessitate medical treatment and can be treated at home without difficulty.
  • Most canker sores will naturally heal within 2 weeks if left alone.


canker sore
Canker sores, also known as aphthous ulcers, are a common oral health complaint.

A canker sore is a type of mouth ulcer that is referred to as an aphthous ulcer in medical terms. Canker sores are one of the most prevalent problems that people have in the oral cavity.

They can affect people of any age, but they are more common in young adults and women.

Canker sores can emerge in children as early as 2 years of age, however they usually do not appear until puberty or later.

Although the majority of people have just occasional canker sores, approximately 20-30 percent of the population suffers from recurrent bouts.

In some cases, canker sores are classified into two categories:

Simple canker sores: They arise three to four times a year, are most common in people aged 10 to 20, and stay for about a week on average.

Complex canker sores: They are less prevalent, bigger, and more painful than simple canker sores. They can last for up to one month and leave a scar on the skin. In many cases, underlying conditions such as a damaged immune system, Crohn’s disease, or vitamin deficiencies are responsible for the development of complex canker sores.


Despite the fact that researchers have not yet established a scientific explanation for how and why canker sores develop, there are some elements that have been identified as being involved, such as viral infection.

The reasons of recurring occurrences of canker sores – also known as recurrent oral aphthous ulcers or recurrent aphthous stomatitis – are similarly unknown, while there is evidence that they are linked to a number of factors, including a family history of aphthous ulcers and allergies, as well as stress.

Aside from inflammatory bowel disease, ulcers are sometimes associated with other conditions that require medical attention. These conditions include weakened immunity, allergies, and nutritional deficiency.

Canker sores are thought to be caused by a combination of circumstances, including the ones listed below:

  • Hormonal changes.
  • Physical trauma (damage to the lining of the mouth, such as during dental treatment).
  • Drugs.
  • Food hypersensitivity – for instance, citrus fruits and tomatoes can trigger or worsen a canker sore.
  • Nutritional deficiencies, including iron, folic acid, zinc, and vitamin B12.
  • Stress.

Recurrent canker sores affect up to 25 percent of the general population, according to a research by the United States Surgeon General, with higher rates among certain categories, such as medical students and nurses.


Canker sores are characterised by localised pain and the ability to become quickly inflamed. The pain may induce sentiments of being fed up with the mouth ulcer in basic situations, but in more complicated cases, those were the only symptoms.

Canker sores are characterised by the following characteristics:

  • The mucosal surface of the mouth is well-defined, round, and less than a centimetre across. It is usually shallow in the lining of the mouth – mucosa.
  • Prior to their appearance, there may be a tingling sensation experienced.
  • The centre is white or yellow-gray, and it is encircled by an inflammatory red border.
  • Over time, the colour is frequently faded to grey.
  • There are several locations where this can occur, including the front section of the mouth, on its floor, inside of the lip (labiodental mouth), inside of the cheeks (buccal), and under or on either side of the tongue.
  • The gums are occasionally affected, as is the surface of the back half of the mouth, which is a somewhat uncommon occurrence.
  • Typically, the condition lasts for 1-2 weeks before disappearing.

Symptoms of some more severe cases can include the following:

  • feeling sluggish
  • swollen lymph nodes
  • fever

Cold sores and canker sores

  • Canker sores appear as white circles with a red halo; cold sores are normally fluid-filled blisters.
  • Canker sores appear inside the mouth; cold sores appear outside the mouth- often under the nose, around the lips, or under the chin.
  • Canker sores are not contagious; cold sores are caused by the herpes simplex virus (HSV) and, more rarely, HSV-2 (the genital herpes virus). Cold sores are contagious.

Time to see your doctor

The majority of common canker sores heal on their own, without the need for medical intervention. Even though prescription treatments do not “cure” ulcers, they can help to alleviate the symptoms of more severe or recurrent ulcers.

As a general rule, canker sores should be brought to the attention of a dentist or doctor if they are accompanied by any of the following symptoms:

  • Continue for more than 2 weeks without showing signs of improvement.
  • Get worse — even when receiving treatment at home with natural therapies.
  • Recur frequently (at least twice a year, if not more frequently), or are exceptionally numerous or severe.
  • Are accompanied by other symptoms such as fever, diarrhea , headache, or a skin rash.
  • Are considered to be a component of another condition.


The good news is that there are many over-the-counter and prescription medications, as well as over-the-counter and home remedies, that can help to alleviate the pain and discomfort of canker sores.

Simple occurrences of occasional canker sores are self-limiting; they will heal over and disappear on their own without the need for further treatment. There are no established therapies for canker sores that can alter the course of the sores themselves or prevent them from recurring — treatments are largely used to alleviate pain, discomfort, and complexity.

Only a few of the canker sore remedies now on the market have undergone substantial clinical testing.

Symptomatic relief, reduction of inflammation, and promotion of the healing process are the primary goals of canker sore treatment, which includes preventing secondary effects that could hinder the healing process, such as bacterial infection.

Treatments may include steroid mouth rinses, topical anaesthetics, antiseptic ointments/rinses, and nutritional supplements, amongst other alternatives.

Home remedies for canker sores

It is recommended that you follow the following home remedy three or four times a day, according to the United States Library of Medicine:

  • Use a mild over-the-counter mouthwash or salt water to rinse your mouth (do not swallow).
  • Combine half hydrogen peroxide and half water in a mixing bowl and stir well.
  • Directly apply some of the mixture to the sore using a cotton swab after mixing it.
  • Apply a small amount of milk of magnesia directly to the hurting spot.

It may also be worthwhile to experiment with so-called alternative therapies. According to a review published in the journal American Family Physician, there are a variety of treatments for treating canker sores, while it was highlighted that there had been no randomised controlled trials to thoroughly verify safety and efficacy:

  • Anecdotes of relief and better healing from sucking on zinc gluconate lozenges (sold for the common cold).
  • Vitamin C, vitamin B complex, and lysine “may speed healing when taken orally at the onset of lesions.”
  • Sage and chamomile mouthwash 4-6 times a day may help – infuse equal parts of the two herbs in water.
  • Carrot, celery, and cantaloupe juices “have been reported as helpful.”

Prescription therapies for canker sores

A doctor should be consulted in cases of canker sores that are more severe or persistent in order to rule out any connected disorders or to obtain prescription medications.

Again, medications focused targeting the ulcers themselves are not guaranteed to alter the course of the disease, although they can alleviate the symptoms.

No matter whether or not there is a bacterial infection present, antibiotics may be administered to reduce inflammatory discomfort.

Canker sore anaesthetics are not only accessible as over-the-counter medicines for canker sores, but they can also be prescribed as topical preparations to relieve irritation and pain.

Some medications that are intended for other conditions can occasionally be used for this one. Canker sores are associated with an overactive immune system, according to the American Academy of Oral & Maxillofacial Pathology, which suggests that topical immunosuppressant drugs, such as topically applied cortisone, may be beneficial in some circumstances.

Topical corticosteroids, which have a similar method of action, are frequently considered by clinicians; these include clobetasol ointment, dexamethasone rinse, and fluocinonide gel, among others (Lidex). A fungal infection in the mouth is a side effect of using corticosteroids to treat canker sores. This is something to be aware of.

Cases of canker sores that are particularly severe or recurrent may be referred to an oral specialist, who may recommend systemic medications rather than locally applied (topical) medications.

Depending on the situation, these professionals may also be required to make a more specific diagnosis — for example, Sutton disease is diagnosed in some uncommon cases of recurrent canker sores.


There is no definitive answer to the question of what may be done to prevent canker sores from developing in the first place. There are, however, techniques to keep canker sores from getting worse or worsening in appearance.

Avoid the following foods to prevent aggravating canker sores:

  • Foods that are abrasive or have the potential to stick in the mouth (potato chips, for example).
  • Foods and beverages that are spicy, acidic, or hot.
  • Traumatizing the ulcers (through harsh contact with toothbrush bristles, for example).

Obianuju Chukwu

She has a degree in pharmacy and has worked in the field as a pharmacist in a hospital. Teaching, blogging, and producing scientific articles are some of her interests. She enjoys writing on various topics relating to health and medicine, including health and beauty-related natural treatments, the nutritional worth of various foods, and mental wellness.