Dear Doctor Column, May 7, 2007

Relief from Painful Canker Sores   

Question:

What causes mouth ulcers? I’ve had them off and on since I was a kid. Is there anything I can do for the pain while they heal?

Answer:

Mouth ulcers, or canker sores, are painful, small, shallow,  red-rimmed craters in the lining of the mouth that usually appear inside the cheeks or lips. Ranging in size from the head of a pencil to the size of a quarter, these noncontagious ulcers can make eating and talking painful. Most heal in 1 to 2 weeks

About 20% of Americans have canker sores, which tend to run in families. They are most common in teenagers and young adults and are slightly more common in women than in men. Although most people experience only a few episodes of canker sores a year, some individuals have a more severe form with virtually continuous ulcers that can take up to a month to heal.

Emotional or physical stress can trigger canker sores, as can minor injuries to the lining of the mouth, such as friction from dentures or braces, biting the inside of your cheek, or scratching your mouth with a toothbrush or sharp, abrasive foods like pretzels and potato chips. For some people, eating certain foods — nuts, chocolate, or citrus fruits  — increase their risk of developing sores, perhaps due to a mild allergic response. Nutritional deficiencies (iron, folic acid, and vitamin B-12) can cause canker sores, as well. However, for most people, no cause is found for the painful problem.

For temporary relief, avoid abrasive, spicy, and acidic foods and beverages, such as fruit juice. Rinsing your mouth with warm salty water (use 1 teaspoon of salt per quart of water) may bring relief, as can ice and over-the-counter pain-relieving gels or ointments. Several medicine-chest staples — liquid Benadryl, milk of magnesia, and Kaopectate — can soothe canker sores; don’t swallow the substances, apply a dab to the affected area with a cotton swab to protectively coat the sore. You also can try diluting 1 tablespoon of hydrogen peroxide in a glass of water and rinsing your mouth to disinfect the sore and speed healing.

Because certain toothpastes or mouth rinses can aggravate existing ulcers, use a bland toothpaste (those marketed for children are good because they usually contain fewer chemicals than those designed primarily for adults) or even baking soda for the days sores are most painful. For persistent oral sores, consult your dentist, who may prescribe a special mouthwash, corticosteroid salve, or numbing solution, such as Xylocaine.

To help avoid future outbreaks of canker sores, eat a balanced diet, try to reduce stress, use a soft toothbrush to lessen the chance of injuring delicate mouth tissue, and see your dentist regularly. If ulcers continue to recur, it is important to work with your dentist to explore habits or other problems that may be causing ulcers to form. Occasionally, frequent canker sores may be a sign of a more serious medical condition, such as an inflammatory bowel disease, infection, or immune disease.