What are Canker Sores?
Canker sores (aphthous ulcers) form on the inside of the mouth and are open and painful. They appear as small white or grey lesions which have a border of red inflamed tissue.
These are the most common type of mouth ulcers found in the general population and are not contagious. They usually start in childhood or teenage years and affect 20 percent of people. (1)
Whilst the pain from these ulcers lasts about a week, they usually clear up of their own accord within two weeks. (2)
The exact cause of canker sores is unknown but could be due to a number of factors which include:
Minor injuries to the inside of the mouth can result in the formation of canker sores. You might accidentally bite the inside of your cheek or have a sharp tooth that catches your lip. Dental fixtures like braces can irritate the gums and cheeks, as can brushing your teeth too vigorously. (3)
Toothpaste and Mouthwash
Certain toothpastes and mouthwashes containing sodium lauryl sulphate can predispose you to developing canker sores. This is particularly the case if you have had these ulcers before. (4)
Sensitivity to certain foods, like cinnamon, citrus, cheese, figs or pineapple can cause the formation of canker sores. Some foods can also make these ulcers more painful.
Lack of Vitamins and Minerals
Deficiency of certain vitamins and minerals can lead to canker sores. These are vitamin B1, B2, B6 and B12 and iron, folic acid and zinc. (7)
Poultry, fish, meat, nuts, beans and dairy products are good sources of B vitamins and zinc. Dark green leafy vegetables like broccoli, spinach, brussel sprouts and cabbage greens are also good sources of vitamins and minerals.(8,9,10,11)
Certain types of bacteria may interact with cells in the mouth either causing ulcers or promoting an immune response where sores develop. These bacteria include streptococcus and helicobacter pylori, a bacteria that also causes peptic ulcers. (12)
Hormonal changes during menstruation in women can leave them more susceptible to the occurrence of canker sores. (13)
Stress can affect people in many ways and it may be a trigger for canker sores. One study has shown that relaxation therapy has a positive effect on the management of mouth ulcers. (14)
Whilst medications are prescribed to treat illnesses some have unpleasant side effects. Drugs that can trigger canker sores include antibiotics, diuretics, anti-inflammatories, antiepileptics and chemotherapy drugs. (15)
Some diseases present with symptoms that include canker sores. They include celiac disease, inflammatory bowel disease and crohn’s disease.
Diseases of the gastrointestinal tract stop nutrients being absorbed from foods that we eat. They can be the result of allergies to foods which contain gluten or an intolerance to certain foods. As a result deficiencies of vitamins and minerals can arise. (16)
Behcet’s disease is a rare inflammatory disorder that affects the blood vessels and tissues. It causes both mouth and genital ulcers. (17)
HIV is a condition that affects the bodies immune system. Canker sores are often experienced as a symptom of this viral infection. (18)
Canker sores tend to be round or oval with a white, greyish or yellow center surrounded by a red inflamed border.
They appear in various places inside your mouth. For example, they can be inside your lips or cheeks, on or under your tongue or at the base of your gums. You can sometimes get them on the soft palate at the back of your throat.
There also may be a tingling or burning sensation felt a few days before the sores become visible.
There are three types of canker sores: minor, major and herpetiform.
Minor sores are found on the inside of lips and cheeks, on the tongue or the floor of the mouth. They are round or oval in shape, and smaller than 10mm across and normally clear in about 2 weeks. There will normally be up to five in number and they are unlikely to leave any scars.
Major canker sores develop on the inside of the lips, the soft palate or at the back of the throat. They will again be round or oval and larger than 10mm in diameter, lasting up to six weeks or more. There will be between one to ten of them and there is a risk of scarring.
Herpetiform canker sores are small deep ulcers, about 2-3 mm in size. They appear on the inside of the lips or cheeks, the tongue, the floor of mouth or on the gums. Numbering between 10 and 100 they are more common in women and usually clear within a month.
Despite their name these canker sores bear no relation to sores caused by the herpes virus. (19)
As we have mentioned canker sores are not cold sores. Cold sores are caused by the herpes virus and appear on the outside of the mouth and are contagious. (20)
Most canker sores will not need medical intervention, they will usually clear up quite quickly. There are over the counter medications that can relieve the pain, prevent infection and promote healing. (21)
However when ulcers are recurrent, become more painful or last more than a few weeks you need to see a doctor. Dentists can also help in diagnosing and treating canker sores.
After enquiring about your medical history the medical professional will examine your mouth. They will check your lips, tongue, cheeks, gums and the back of your throat.
Usually this will be sufficient for a doctor to diagnose your condition. There may however be other factors that they will consider, particularly if symptoms are persistent.
Blood tests may be taken to rule out underlying causes like vitamin deficiencies or diseases that present with ulcers as a symptom.
They may also take a swab or sample of the ulcer for analysis to check for infection. (22)
What are canker sores? Canker sores (aphthous ulcers) form on the inside of the mouth and are open and painful. They appear as small white or grey lesions which have a border of red inflamed tissue.
What causes canker sores? The cause of canker sores is not certain however there are many factors that play a part in their development. These include vitamin and mineral deficiencies, food sensitivities, trauma to the inside of the mouth, bacteria, stress and hormones. Canker sores are also an indication of underlying illness and present as symptoms of some immune and gastrointestinal diseases.
How do doctors test for canker sores? These mouth ulcers are generally easily diagnosed by a visual examination by your doctor or dentist. There may be occasions when blood tests, to rule out underlying causes, or tests for infection are required.
When should you go to the doctors with canker sores? Recurrent mouth ulcers are a cause for concern, as are ones lasting longer than a few weeks. If your ulcers become more painful then a visit to a doctor or dentist is advisable. (23)
Can you prevent canker sores? If you know there are foods that trigger an outbreak of canker sores, try and avoid them. Reducing stress can also help prevent sores developing. Eat a healthy diet rich in foods that provide you with B vitamins, iron and zinc. Make sure your toothbrush is not too hard and if you have any sharp fillings or teeth see your dentist.
What can relieve canker sores? There are over-the-counter and prescription medications that help relieve pain and promote healing. These are particularly effective when applied to as soon as sores appear. (24)
Are there any complications from canker sores? Canker sores can cause issues when eating, cleaning your teeth and talking depending on where they are. Some medications used to treat these ulcers can cause thrush of the mouth. (25)
Are canker sores hereditary? There are many factors that are taken into account in relation to the cause of canker sores. There have been studies conducted which suggest genetic makeup inherited from our families contribute to predisposition for this condition. The chances are if close family members are susceptible to canker sores then you will be too. (26,27)
Canker sores develop on the inside of the mouth and are open and painful. These small white or grey lesions which have a border of red inflamed tissue can be painful.
There are many things that predispose people to this condition but the actual reason they manifest is not known. The good thing is that they are easily diagnosed and treated.
Unfortunately if your close family members suffer from canker sores then the chances are you will too.
Ensuring good oral hygiene practices and avoiding things that you know predispose you to an outbreak can prevent canker sores.
It’s important not to confuse canker sores, with cold sores. Cold sores are caused by the herpes virus and appear on the outside of the mouth. This type of sore is highly contagious, therefore easily spread through contact.