Common Causes And Risk Factors For Canker Sores

September 3, 2023

Canker sores are painful, round ulcers that form inside the mouth, on the inside of cheeks or lips, and along the tongue and gums. They are usually yellow or white lesions in the center with a vivid red border. Most individuals will have one to three canker sores at a time, but some suffer from more severe infections with up to a dozen lesions spread around the mouth at once. Canker sores are sore and annoying, but luckily they usually go away on their own. They are most commonly seen in children and teens between ten and twenty, but recurring cold sores frequently occur once you've had others. There are several theories about their triggers including injuries, food sensitivities, and a lack of vital nutrients. Sometimes they are also a symptom of other diseases.

Keep reading to discover the common causes of canker sores.

Mouth Injury

Any mouth injury can cause canker sores because the inflamed or sore tissue is more vulnerable to ulcers. Small ulcers may form after mild irritation from a sharp-bristled toothbrush or biting into a hard or sharp piece of food. Additionally, certain harsh mouthwashes can damage or inflame the lining inside your mouth, which as discussed, can result in canker sores. These lesions usually will go away on their own once they have had a chance to heal. If you suspect a brush or mouthwash is to blame, try replacing it with something gentler.

Poorly fitted dental equipment, such as dentures or braces, can also cause mouth soreness and inflammation. In this case, it is better to see your dental professional and have them correct the fit so your mouth will have a chance to heal. Sports and other accidental mouth injuries may cause canker sores, but those usually go away within two weeks.

Continue reading to discuss what common ingredient in many products can result in canker sores.

Products With Sodium Lauryl Sulfate

Sodium lauryl sulfate is an ingredient found in some types of toothpaste that has been linked to canker sores. Its especially powerful foaming action can damage your skin's proteins and dry out the inside of your mouth. Dental products with sodium lauryl sulfate are relatively inexpensive to manufacture and leave consumers with an extra-clean feeling in their mouths, which is a big part of what makes them so popular. For some individuals, however, it works too well at keeping their mouths clean and can actually cause canker sores to break out because their mouth's skin doesn't have the protection and moisture it needs.

Continue reading to learn how specific sensitivities might result in canker sores.

Food Sensitivities

Some fruits and vegetables may or may not cause canker sores, but for individuals who already have them or suffer from them frequently, highly acidic citrus fruits, spicy foods, coffee, and chocolate can trigger or make the sores worse. The open lesion inside of a canker sore can also leave your mouth extremely sensitive to any acidic foods you eat. Foods such as strawberries, tomatoes, and apples should also be avoided when you have canker sores. Some auto-immune conditions, such as celiac disease, can cause canker sores too. Food allergies can sometimes lead to canker sores and are another food sensitivity issue to be aware of when trying to determine the cause.

Keep reading to learn how stress can cause canker sores.


If you have been suffering from a lot of stress, know it can also cause canker sores. Not only do stressed individuals often experience sharp changes in their diet, but the stress also leads to negative behaviors in the mouth such as teeth clenching and grinding, which may injure the cheeks and lips. Those injuries then lead to sores inside the mouth.

Feeling stressed can also weaken the body's immune system and lowered immune responses have been shown to either cause or worsen canker sores. Hormonal changes, especially those experienced in adolescence, can lead to stresses throughout the body and have been linked to causing canker sores.

Continue reading to learn about when diet might result in canker sores.

Lack Of Nutrients In Diet

Diet and nutrients play a key role in preventing many skin and mouth diseases, including canker sores. One vitamin deficiency that often causes ulcers, especially in children, is a B-12 deficiency. Growing kids require even more B-12 than adults and, unfortunately, tend to avoid the fruits and vegetables that have it in abundance, making a B-12 deficiency quite common in children and teens, but adding a B-12 supplement or applying the contents of B-12 vitamin capsules directly to the sores can help treat and prevent the issue.

Other nutrient deficiencies have also been linked to canker sores. A lack of nutrients, particularly folic acid, iron, and zinc, can cause canker sores or make them worse. A lack of calcium may not directly cause canker sores, but it has been shown to make them worse. For these nutrient deficiencies, making simple diet changes to foods rich in all four can create the biggest difference.

Discover additional information about the causes and risk factors for canker sores now.

Helicobacter Pylori

Helicobacter pylori is a type of bacteria that can cause stomach ulcers and stomach infections, as well as increase the risk of canker sores. Helicobacter pylori infections are particularly common in childhood. Patients with this infection may experience nausea, abdominal pain, frequent burping, bloating, and loss of appetite. Unintentional weight loss might occur. Some individuals with a Helicobacter pylori infection never display any symptoms. This infection is a frequent cause of peptic ulcers, and patients who have ulcers are normally tested for the Helicobacter pylori bacteria. Blood tests, breath tests, stool tests, and endoscopic tests may be used for diagnostic purposes. To treat this infection, doctors often prescribe two or more antibiotics. Medications that suppress stomach acid, including proton pump inhibitors, H-2 (histamine) blockers, and bismuth salicylate may be prescribed to help the stomach heal. Patients are tested for Helicobacter pylori roughly four weeks after completing treatment. If the infection is still present, the patient will need to have another round of treatment with different antibiotics.

Uncover more risk factors and causes of canker sores now.

Crohn's Disease

Crohn's disease is a type of inflammatory bowel disease that causes chronic inflammation in the digestive tract. Patients with this condition go through symptomatic episodes that may be followed by periods of remission. During an episode, the patient could have a fever, fatigue, diarrhea, abdominal pain, canker sores, blood in the stool, weight loss, and reduced appetite. If an anal fistula is present, there may be pain or drainage around the anus. Individuals with severe Crohn's disease might experience inflammation of the liver, bile ducts, joints, skin, or eyes, and children may have delayed growth and sexual development. To diagnose Crohn's disease, doctors will perform blood tests, and patients may need to have a colonoscopy, CT scans, MRI scans, balloon-assisted enteroscopy, or capsule endoscopy. Anti-inflammatory medicines are typically recommended as the first line of treatment. Patients may be prescribed corticosteroids for three to four months, and oral 5-aminosalicylates could be considered for certain individuals. Immunosuppressants such as methotrexate might be recommended, and some patients may need to take antibiotics like metronidazole or ciprofloxacin. Nutritional therapy with a feeding tube may be necessary during treatment for Crohn's disease, and patients who do not respond to medications and other therapies might need to have surgery. Surgeons will remove the damaged portion of the patient's digestive tract, and the healthy sections of the digestive tract will be reconnected. Some individuals may need to have more than one surgery.

Keep reading to learn more about what can trigger the development of canker sores now.

Hormonal Shifts

For women, hormonal shifts during menstruation may lead to the development of canker sores. Estrogen levels tend to be higher in the week before menstruation, and this can cause inflammation in the mouth. The gums may swell, and the mouth could be more sensitive than usual, increasing the risk of canker sores. The mouth's mucosal lining thickens during menstruation, which also increases the risk of canker sores. To keep the mouth comfortable during this time, patients should be very diligent about maintaining their dental hygiene routine, including flossing, brushing, and using mouthwash. It can help to avoid foods that could irritate the mouth such as pineapple, oranges, grapefruit, salty foods, nuts, and chips. Patients who get canker sores regularly before or during menstruation may want to speak to a dentist about pain-relieving mouth gels that could help. Some individuals might want to talk to a doctor to learn more about what can be done to reduce the impact of hormonal shifts.

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Age And Gender

Age and gender could both influence a patient's likelihood of getting a canker sore. These sores appear to be more common in female patients, and they are particularly common in teenagers and young adults. Although the reasons for this are unknown, it could be that patients in this age group are less likely to follow a healthy diet. As a result, they could have nutritional deficiencies in iron, vitamin B12, zinc, or folic acid that may increase their risk of mouth sores. Individuals in this age group tend to have a high level of stress, which is a recognized risk factor for mouth sores. In females, hormonal changes before and during menstruation are known to influence the development of canker sores too. Patients of any age and gender who get canker sores regularly should speak to their doctor for diagnosis and treatment.

Learn more about the causes and risk factors for canker sores now.

Ulcerative Colitis

Ulcerative colitis can increase the risk of developing canker sores. The condition inflames the colon and rectum, and ulcers may form in these areas. Patients with ulcerative colitis could experience pain in the stomach, rectum, and joints, and they may also notice rectal bleeding, diarrhea, or constipation. Some individuals may develop a fever, and sudden weight loss has occurred. To diagnose this condition, doctors perform blood tests to check for anemia, and patients might need to have x-rays, CT scans, stool tests, and a colonoscopy or sigmoidoscopy. Medications such as corticosteroids, immunomodulators, and anti-inflammatories like sulfasalazine may be recommended. Patients might need to make dietary modifications as well. For example, they might need to avoid high-fiber foods like beans, legumes, and whole grains, and they could also be advised to avoid alcohol, caffeine, and carbonated drinks. In severe cases of ulcerative colitis, the patient's healthcare provider may recommend surgery. Surgical options such as ileoanal anastomosis, proctocolectomy, and colectomy could be considered.

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