Mouth Ulcers (Canker Sores)

Symptom Definition

  • Painful, shallow ulcers (sores) on the lining of the mouth
  • The gums, the cheeks or inner sides of the lips are the usual sites
  • Sores on the outer lips (e.g. recurrent fever blisters) are excluded
  • Main Cause: canker sores
  • Common cause age 1- 3 years: first infection with herpes virus (cold sores virus)

See More Appropriate Topic

  • If have thick-walled, small-blisters on the palms or soles, in addition to mouth ulcers, see Hand-Foot-Mouth Disease

Call Your Doctor Now (night or day) If

  • Your child looks or acts very sick
  • Chemical in the mouth could have caused ulcers
  • Signs of dehydration (very dry mouth, no tears and no urine in > 8 hours)

Call Your Doctor Within 24 Hours (between 9 and 4) If

  • You think your child needs to be seen
  • 4 or more ulcers
  • Red, swollen gums
  • One ulcer on the gum near a tooth with a toothache
  • Fever or swollen face
  • Large lymph node under the jaw
  • Began after starting a medicine

Call Your Doctor During Weekday Office Hours If

  • You have other questions or concerns

Parent Care at Home If

  • Probable canker sores and you don’t think your child needs to be seen

Home Care Advice for Canker Sores (Benign Mouth Ulcers)

  1. Canker sores: the #1 cause of mouth ulcers
    • 1 to 3 painful, white ulcers of the inner cheeks or gums (no fever)
    • Causes include injuries from rough food, tooth brushes, biting, food irritants, etc.
  2. Antacid for Pain Relief: Use a liquid antacid 4 times per day for pain relief. Children over age 4 can use 1 teaspoon as a mouth wash after meals (Some parents prefer regular mouth washes, but they may sting.) For younger children, put 1/2 teaspoon in the front of the mouth after meals
  3. Pain Medicine: Give acetaminophen or ibuprofen for severe pain (especially at bedtime)
  4. Soft Diet: Offer a soft diet. Encourage favorite fluids to prevent dehydration. Cold drinks, milkshakes, and Popsicles are especially good. Avoid salty foods, citrus fruits and foods that need much chewing. For infants, give fluids by cup rather than a bottle. (Reason: the nipple can cause pain)
  5. Contagiousness: Canker sores are not contagious. Children with fever or many mouth ulcers need to be examined before returning to day care or school.
  6. Expected Course: They heal up in 1 to 2 weeks. Once they occur, no treatment can shorten the course, but treatment can reduce the amount of pain
  7. Call Your Doctor If
    • Mouth ulcers last > 2 weeks
    • Our child becomes worse or develops any of the “Call Your Doctor” symptoms