We’ve all had them – those dreaded canker sores.

They can be painful and can make eating and talking difficult. Canker sores, also called aphthous ulcers, are a common, painful sore in the mouth that might appear on the inner portion (mucosa) of the lips and cheeks, or on the gums.

Q: What causes canker sores?

A: The cause of a canker sore usually cannot be determined. They’re auto-immune, which means that your body is basically attacking itself. Canker sores might also occur after an injury to the mouth following dental work, aggressive tooth brushing or biting the tongue or cheek.

Canker sores can also be triggered by the following:

  • Emotional stress
  • Lack of certain vitamins and minerals in your diet (especially iron, folic acid or vitamin B-12)
  • Hormones

Also, the tendency to develop canker sores might run in families.

Q: How do you know if you actually have a canker sore?

A: Symptoms include:

  • One or more painful, red spots or a bump that develops into an open ulcer
  • Middle of the sore is white or yellow
  • Usually small (under 1 cm) but occasionally larger
  • Sore might turn gray just before starting to heal

Some cases of canker sores might be associated with fever or swollen lymph nodes (glands) in the neck, but these are less common symptoms.

Q: How long do canker sores last?

A: The pain caused by a canker sore usually goes away after 7 to 10 days, but it might take one to three weeks for the sore to completely heal.

Large canker sores might take longer to heal.

Q: What’s the difference between a canker sore and a cold sore?

A: A canker sore is not the same as a fever blister (cold sore) that is the result of a herpes virus infection.

Unlike cold sores, canker sores don’t occur on the surface of your lips and aren’t contagious.

Q: How are canker sores treated?

A: Most canker sores will heal on their own, but here are a few treatments that can sooth and may also help the sore heal:

  • Avoid eating spicy foods that can irritate the sore.
  • Rinsing your mouth with salt water might offer some relief.
  • Some over-the-counter medicines can be applied directly to the sore and might offer temporary pain relief.
  • One home remedy is to create a mixture of half hydrogen peroxide and half water. Use a cotton swab to apply the mixture directly to the canker sore.
  • A small dab of Milk of Magnesia might also be applied to the sore with a Q-tip 3 to 4 times a day.

Prescription medications might be recommended for severe cases.

While most canker sores will heal on their own, if you have a sore that is unusually large or painful or one that persists, call a dermatologist.

Dr. Oswald Lightsey Mikell, certified by the American Board of Cosmetic Surgery, is the owner of Dermatology Associates of the Lowcountry.