What Causes Canker Sores in the Mouth?

 Canker sores, also known as aphthous ulcers, are small, shallow lesions that develop on the soft tissues in your mouth or at the base of your gums. They can be caused by several different factors. Canker sores, on the other hand, do not appear on the surface of your lips and they are not contagious in the same way that cold sores are. 

The discomfort they cause can make it difficult to eat and talk, and they may even cause pain. The majority of canker sores heal on their own within a week or two at the most. If you have canker sores that are unusually large or painful, or if you have canker sores that don’t appear to be healing, you should talk to your doctor or dentist.

Canker Sores: Why Do We Get Them?

Canker sores are not contagious and cannot be passed on through saliva, but the exact cause of the majority of canker sores is a mystery to medical science. They may be the result of an injury, such as when you bite your cheek inadvertently or when braces catch or rub against the inside of the cheeks or the back of the lips, but more often than not, they appear as if out of thin air. Having a weakened immune system, being dehydrated, having allergies, being under a lot of stress, or even taking certain medications can bring on an attack.

Other Causes of Canker Sores

Canker sores have not yet been scientifically explained; however, some factors are known to be involved, including viral infection. Researchers have not yet provided a scientific explanation of why canker sores develop. Although the causes of recurrent cases of canker sore, also known as recurrent oral aphthous ulcers or recurrent aphthous stomatitis, are unknown, there are links with several factors, including a family history of aphthous ulcers, and allergies. In addition, some people are predisposed to developing canker sores due to genetics. Ulcers are frequently associated with several other conditions that require medical attention, including inflammatory bowel disease, allergies, compromised immunity, and nutritional deficiency.

The Symptoms of Canker Sores

The majority of canker sores have a white or yellow core with a red border and can be round or oval in shape. They can develop anywhere inside your mouth, including on or under your tongue, within your cheeks or lips, at the base of your gums, on your soft palate, or anywhere else. Before the sores appear on your skin, you may feel a tingling or burning sensation one or two days beforehand.

Types of Canker Sores

1. Simple Canker Sores

These can occur anywhere from three to four times per year and can last for up to a week each time.

2. Minor Canker Sores

The most common type of canker sore is a minor canker sore, which is typically very small, has an oval shape with a red edge, and heals completely without scarring in one to two weeks.

3. Major Canker Sores

Major canker sores are less common than minor canker sores and are larger and deeper than minor canker sores. They are typically round with defined borders, but when they are very large, they may have irregular edges. Major canker sores can be extremely painful, and it may take up to six weeks for them to heal completely, and they can leave extensive scarring.

4. Herpetiform Canker Sores

Herpetiform canker sores are not caused by an infection with the herpes virus, even though they are uncommon and typically appear later in life. These canker sores are about the size of a pinhead, and typically appear in clusters of ten to one hundred sores, but they can also combine into one large ulcer. They have irregular edges and heal in one to two weeks without leaving scars.

Cold Sore vs. Canker Sore

There is a difference between canker sores and cold sores. Herpes simplex type 1 is the virus that causes cold sores, which are groups of painful blisters filled with fluid and also known as fever blisters. Cold sores are caused by a virus, not an infection like canker sores, and they are highly contagious. Canker sores, on the other hand, manifest themselves on the inside of the mouth, while cold sores manifest themselves on the outside of the mouth, typically under the nose, around the lips, or under the chin.

The Following Elements Contribute to the Emergence of Canker Sores:

1. Hormonal Adjustments

Damage to the lining of the mouth is caused by physical trauma, such as that which occurs during dental treatment.

2. Drugs

Hypersensitivity to certain foods, such as citrus fruits and tomatoes, can bring on or exacerbate the symptoms of canker sores. Deficiencies in essential nutrients, such as iron, folic acid, zinc, and vitamin B12.

3. Stress

The United States Surgeon General has published a report in which he estimates that up to 25 percent of the general population is affected by recurrent canker sores. The report also notes that the prevalence of the condition may be higher in certain groups, such as students studying to become health professionals.

When to Visit the Doctor

Relatively common canker sores typically heal on their own without the need for medical treatment. Even though these treatments do not “cure” the ulcers, they may be able to alleviate symptoms in cases that are more severe or occur repeatedly. Canker sores should be brought to the attention of a dentist or doctor when they persist for more than two weeks without improving, get worse including while being treated with home remedies, recur often 2-3 times a year or more, or are particularly numerous, or severe, are accompanied by other symptoms, such as fever, diarrhea, headache, or skin rash, and are thought to be part of another condition. As a general guide, canker sores should be brought to the attention of a dentist or doctor.


The good news is that the pain and discomfort caused by canker sores can be alleviated with treatments that are easily accessible, including treatments that do not require a prescription, treatments that do not require a prescription, and home remedies. Canker sores that occur only occasionally and in mild cases heal on their own and go away on their own without the need for medical treatment. It has not been established that any treatments can alter the natural progression of canker sores or prevent them from reappearing; most treatments merely alleviate the associated pain, discomfort, and complications. 

Canker sore treatments are scarce, and even fewer of them have been subjected to rigorous clinical research. Canker sores are managed by treating the symptoms, decreasing inflammation, and promoting the healing process by preventing secondary effects, such as bacterial infection, that could slow down the healing process. Mouth rinses containing a corticosteroid, topical anesthetics, antiseptic ointments or rinses, and nutritional supplements are some of the possible treatments.

There is no definitive response to the question of how canker sores can be avoided in the first place because there is none. Canker sores, on the other hand, are treatable, and there are ways to stop them from becoming more painful or spreading.