Canker Sores
February 22, 2010

Parents have been asking me a mouthful of questions as to whether or not their child has a canker sore and what to do about it. Well, I don’t want anyone to be sore at me about this topic, so let me provide some information.

About 1 in 5 children develop canker sores, also known as mouth ulcers. They are small red ulcers that occur inside the mouth, not to be confused with cold sores that occur outside the mouth. While cold sores are very contagious, canker sores are not - although the tendency to get them can run in families. The good news is that canker sores are not dangerous.

What causes a canker sore? We know that cold sores are caused by the herpes virus, but no one knows exactly what causes a canker sore. Some factors that may increase the occurrence of them include:


It may take up to two weeks for canker sores to heal, although the pain is usually worse in the first few days. If the pain is severe or your child cannot drink or eat because of the pain, talk to you child’s doctor who will want to confirm the diagnosis, try to find a cause and help with treatment.

Besides tincture of time which usually involves a week or so for the ulcers to heal, sometimes your doctor will recommend acetaminophen for the pain as well as an over the counter mouth rinse or medication to put on the sores, or to swish and swallow for relief. These mixtures both numb the area and coat the ulcer making it easier for a child to stay hydrated by eating and drinking. Avoiding spicy, salty or tart foods can also go a long way to reducing the discomfort caused by a mouth sore.

Hopefully tips like this will burn brightly in your mind, rather than burn in your child’s mouth, the next time you are worried they have a canker sore.

Lewis First, M.D., is chief of Pediatrics at Vermont Children's Hospital at Fletcher Allen Health Care and chair of the Department of Pediatrics at the University of Vermont College of Medicine. You can also catch "First with Kids" weekly on WOKO 98.9FM and on WCAX-TV Channel 3. Visit the First with Kids video archives at