OhioHealth Online

Canker sores, also called aphthous ulcers, are small, shallow lesions that develop on the soft tissues in your mouth — under your tongue, inside your cheeks or lips, and at the base of your gums. Unlike cold sores, canker sores don't occur on the surface of your lips and aren't contagious. They can be very painful, however, and can make eating and talking difficult.

Most canker sores go away on their own in a week or two. Check with your doctor or dentist if you have unusually large or painful canker sores or canker sores that don't seem to heal.

Most canker sores are round or oval with a white or yellow center and a red border. They form inside your mouth — on or under your tongue (soft palate), inside your cheeks or lips, and at the base of your gums. You might notice a tingling or burning sensation a day or two before the sores actually appear.

There are several types of canker sores:

• Minor canker sores. The most common type of canker sore is an oval lesion, less than 1/3-inch (7.62 millimeters) wide that clears on its own in about two weeks. Though not serious, minor canker sores can be very painful.
• Major canker sores. These are large lesions with irregular margins that can last months or even years. They often heal with extensive scarring.
• Herpetiform canker sores. These are clusters of dozens of tiny lesions that may merge to form a single large ulcer. Herpetiform canker sores usually develop later in life and may last from a week to a month or more.

Occasionally, you may experience other signs or symptoms along with the lesions, such as:

• Fever
• Listlessness
• Swollen lymph nodes

The precise cause of canker sores remains unclear, though researchers suspect that a combination of several factors contributes to outbreaks, even in a single individual. These factors include:

• A faulty immune system that attacks healthy cells in your mouth instead of pathogens such as viruses and bacteria
• A minor injury to your mouth from dental work, overzealous brushing, sports mishaps, spicy or acidic foods, or an accidental cheek bite
• An allergic response to certain bacteria in your mouth
• Helicobacter pylori, the same bacteria that cause peptic ulcers
• A diet lacking in vitamin B-12, zinc, folate (folic acid) or iron
• Celiac disease, a serious intestinal disorder caused by a sensitivity to gluten, a protein found in most grains
• Inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis
• Behcet's disease, a rare disorder that causes inflammation throughout the body, including the mouth
• HIV/AIDS, which suppresses the immune system
• Food allergies or sensitivities
• Certain foods, particularly chocolate, coffee, strawberries, eggs, nuts, cheese and highly acidic foods, such as pineapple
• Hormonal shifts during menstruation
• Emotional stress
• Toothpastes and mouth rinses containing sodium lauryl sulfate

Anyone can develop canker sores, but these factors make you more susceptible:

• Your sex. Canker sores, especially clusters of small lesions, are more common in women than in men.
• Age. Most people experience their first outbreak when they're between 10 and 40 years of age. The sores tend to occur less frequently as you get older.
• Family history. As many as 50 percent of people with canker sores have a close family member with the disorder. This may be due to heredity or to a shared factor in the environment, such as certain food or allergens.

Consult your doctor if you experience:

• Unusually large canker sores
• Recurring ulcers, with new ones developing before old ones heal
• Persistent sores, lasting three weeks or more
• Sores that extend into the lips themselves (vermilion border)
• Pain that you can't control with self-care measures
• Extreme difficulty eating or drinking
• High fever along with canker sores

See your dentist if you have sharp tooth surfaces or dental appliances that seem to trigger the sores.

Tests aren't needed to diagnose canker sores. Your doctor or dentist can identify them with a visual exam. In some cases, you may have tests to check for other health problems, especially if your canker sores are severe and ongoing.

Treatment usually isn't necessary for minor canker sores, which tend to clear on their own in a week or two. But large, persistent or unusually painful lesions often need medical care. A number of treatment options exist, ranging from mouth rinses and topical ointments to systemic corticosteroids for the most severe cases.

• Mouth rinses. If you have a number of canker sores, your doctor may prescribe a mouth rinse containing the steroid dexamethasone to reduce pain and inflammation. Oral suspensions of the antibiotic tetracycline also can reduce pain and cut healing time, but tetracycline has drawbacks. It can make you more susceptible to oral thrush, a fungal infection that causes painful mouth lesions, and it can permanently discolor children's teeth.
• Topical pastes. Over-the-counter and prescription pastes such as Orabase, triamcinolone acetonide (Kenalog in Orabase), amlexanox (Aphthasol) and fluocinonide (Lidex) can help relieve pain and speed healing if applied to individual lesions as soon as they appear.
• Oral medications. Medications not intended specifically for canker sore treatment, such as the heartburn drug cimetidine (Tagamet) and colchicine, which is normally used to treat gout, may be helpful for canker sores. Oral steroid medications are sometimes prescribed when severe canker sores don't respond to other treatments. But because the side effects of steroids are so serious, this is usually considered a treatment of last resort.
• Debacterol. This topical solution was specifically designed to treat canker sores and gum problems. By chemically cauterizing lesions, it reduces healing time to about a week.
• Nutritional supplements. Your doctor is likely to prescribe a nutritional supplement if you're low in important nutrients, such as folate (folic acid), vitamins B-6, B-12 and zinc.
• Alternative treatments. There are a number of drug-free options for treating and preventing canker sores, including zinc lozenges, large doses of vitamin C and B complex, probiotics such as acidophilus, and lysine supplements. Some people make a paste of alum, slippery elm powder or deglycyrrhizinated licorice (DGL) and apply it directly to the sores.
• Other conditions. If your canker sores seem to be related to a more serious health problem, your doctor will treat the underlying condition.

Canker sores often recur, but you may be able to reduce their frequency by addressing factors that seem to trigger them:

• Watch what you eat. Try to avoid foods that seem to irritate your mouth. These may include nuts, chips, pretzels, certain spices, salty foods and acidic fruits, such as pineapple, grapefruit and oranges. Be sure to avoid any foods to which you're sensitive or allergic.
• Choose healthy foods. To help prevent nutritional deficiencies, eat plenty of fruits, vegetables and whole grains. Regularly eating yogurt that contains acidophilus or other beneficial bacteria also may help ward off canker sores.
• Don't chew and talk at the same time. You could cause minor trauma to the delicate lining of your mouth.
• Follow good oral hygiene habits. Regular brushing after meals and flossing once a day can keep your mouth clean and free of foods that might trigger a sore. Use a soft brush to help prevent irritation to delicate mouth tissues, and avoid toothpastes and mouth rinses that contain sodium lauryl sulfate.
• Protect your mouth. If you have braces or other dental appliances, ask your dentist about orthodontic waxes to cover sharp edges.

To relieve pain and speed healing:

• Rinse your mouth with salt water, baking soda (dissolve 1 teaspoon of soda in 1/2 cup warm water), diluted hydrogen peroxide or elixir of diphenhydramine (Benadryl). Be sure to spit the Benadryl out after rinsing.
• Cover lesions with a paste made of baking soda.
• Try over-the-counter products that contain a numbing agent, such as Orabase-B, Anbesol and Orajel.
• Avoid abrasive, acidic or spicy foods that can cause further irritation and pain.
• Apply ice to your canker sores or allow ice chips to slowly dissolve over the sores.
• Brush your teeth gently, using a soft brush and toothpaste without foaming agents, such as TheraBreath.
• Dab a small amount of milk of magnesia on your canker sore a few times a day. This can ease the pain and may help the sore heal more quickly.