Ask the Doctor

Question #13:

My child complains about sores in her mouth and our doctor says she has canker sores. What causes them?


Douglas Mitchell, MD, of CHKD Health System’s General Booth Pediatrics, says “Canker sores usually appear as small but painful red spots inside the mouth. They may tingle at first and then swell and burst in about a day. The open sore may have a red ridge around it. Most often these sores pop up alone but they can also appear in clusters. When they do, they can be very uncomfortable. The sores are not contagious. The tendency to get canker sores frequently runs in the family, though allergies or nutritional deficiencies of folic acid, B12 and iron can be factors. They can also indicate an immune system problem, but this is rare. No one really knows what causes canker sores, but they are easily treated and will disappear in a couple of weeks unless an infection occurs. Your doctor can advise about over-the-counter medications or may suggest homemade mouthwash of water and baking powder or water and hydrogen peroxide. Your doctor will help you decide if your child is old enough to gargle without swallowing ingredients in these remedies.

All Questions

  1. My newborn seems to need something to suck on when she’s not eating. Her mouth is in constant motion. Is it OK to give her a pacifier?
  2. What’s an appropriate amount of television for a toddler to watch each day? I’m worried that my grandson is watching too much TV.
  3. Can weight lifting help overweight kids?
  4. My 8-year-old still sucks his thumb. I hate to pressure him to stop and don’t want to shame him, so what should I do?
  5. My teenage son received a paintball gun for his birthday, and I’m reluctant to let him play with it. Are paintball guns safe?
  6. I’m wondering when my child will be old enough to move from the crib to a single bed. Any guidelines I should know?
  7. Help! My teen keeps talking about getting her tongue pierced. What can I tell her to discourage her?
  8. My grandson was born with jaundice. Can you tell me what causes it and whether it’s serious?
  9. My 2-year-old can’t seem to get into a schedule of meals. She’s hardly ever hungry when it’s time for a meal, but other times she wants to eat all day long. I worry that her eating is too erratic and not healthy.
  10. Is it normal for my baby to hiccup a lot?
  11. What should I know about impetigo if my neighbor’s child has it and frequently plays with my child?
  12. My mother says that my 10-month-old daughter should wear hard-soled shoes to learn to walk. When should I start buying shoes for my baby, and what types are best?
  13. My child complains about sores in her mouth and our doctor says she has canker sores. What causes them?
  14. My teenage daughter thinks she’s fat, but she’s normal height and weight for her age. Should I be concerned she has an eating disorder?
  15. My teenage daughter has been told that cramps and nausea she gets after drinking milk or eating cheese or ice cream are due to lactose intolerance. Can you develop such a problem as you get older?
  16. When should my baby start seeing a dentist?