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About mouth ulcers

Mouth ulcers are little sores that come up inside the mouth, on the tongue or on the gums.

Several things can cause mouth ulcers:

  • viral infections like cold sores or hand, foot and mouth disease
  • oral thrush
  • injuries like biting, burns or rubbing from braces
  • low vitamin levels
  • diseases like coeliac disease or inflammatory bowel disease.

Sometimes ulcers keep coming back without any obvious cause.

Symptoms of mouth ulcers

Mouth ulcers usually look like round, white sores on the inner lining of your child’s mouth or on the surface of your child’s gums or tongue.

These sores can be painful, especially when your child eats salty, spicy or sour foods. Sometimes your child might even refuse food until the ulcers start to heal.

If an infection is causing the ulcers, your child might also have a fever.

Medical help: when to get it for children with mouth ulcers

If you think your child might have ulcers related to a mouth infection, it’s a good idea to see your GP.

You should also see your GP if your child’s mouth ulcer doesn’t clear up within 1-2 weeks or if your child keeps getting mouth ulcers.

See your GP urgently if your child develops severe mouth ulcers with symptoms of general illness like:

  • weight loss
  • stomach pain
  • unexplained fevers
  • blood or mucus in poo
  • neck stiffness and tiredness
  • ulcers around the anus.

Tests for mouth ulcers

Your GP might take a swab of your child’s ulcers for testing. This can help the GP work out what’s causing the ulcers.

If your child has other symptoms or has ulcers that keep coming back, your GP might refer your child for a blood test or to a specialist.

Treatment for mouth ulcers

Simple mouth ulcers usually don’t need treatment and clear up within a week.

If your child is in pain, you can try applying a numbing mouth gel to the area. You can buy these mouth gels at your pharmacy. You can also try warm salt water rinses if your child is old enough to rinse or gargle with liquids.

Encourage your child to have enough fluids by offering small, frequent sips of water. This will help to prevent dehydration. Your child should also avoid salty, spicy or sour food.

There are specific treatments for mouth infections caused by thrush and the cold sore virus. Your GP will let you know about these if your child needs them.

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Raising Children Network is supported by the Australian Government. Member organisations are the Parenting Research Centre and the Murdoch Childrens Research Institute with The Royal Children’s Hospital Centre for Community Child Health.

Member Organisations

  • Parenting Research Centre
  • The Royal Children's Hospital Melbourne
  • Murdoch Children's Research Institute

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