• Mouth ulcers and thrush are often seen in young babies and infants.
  • For many mouth lesions, it helps if your child avoids salty, acidic or spicy foods.
  • If mouth ulcers don’t heal within two weeks, a doctor, dentist or other oral health professional should be consulted.
  • Tooth abscess and cellulitis require immediate treatment by your oral health professional or doctor.
It is a good idea to look inside your child’s mouth regularly. Oral thrush, mouth ulcers and cold sores are common problems. The early signs of tooth decay are another thing to look out for. Speak to your doctor, dentist or other oral health professional if you are concerned about anything in your child’s mouth.

Oral thrush

Oral thrush is a fungal infection that affects the soft tissue inside the mouth. It is quite common in young children.

Oral thrush looks like milky white patches in the mouth that can be wiped away easily. The child may also have an infection in the nappy area at the same time. Very rarely a fever and gastrointestinal irritation may show with an oral thrush infection; however this may also indicate a more general infection.

Treatment for oral thrush

Thrush is treated with antifungal medications applied directly to the affected areas. See your doctor or oral health professional.

Mouth ulcers

Mouth ulcers are a type of sore inside the mouth which can have several causes. Traumatic ulcers are a common type of mouth ulcer which results from injury to the mouth; for example, after biting the cheek. Aphthous ulcers are a painful type of ulcer that tends to come back again and again as one or many sores a few millimetres across.

Mouth ulcers usually heal on their own in a week or two. If any ulcer does not heal after two weeks, it is important to see a doctor or oral health professional.

Treatment for mouth ulcers

There is not a lot that can be done to treat mouth ulcers, but you can help to reduce pain by:
  • avoiding acidic foods and drinks, such as oranges and other citrus fruits.
  • making sure children regularly drink water.
  • using a protective gel on the affected area, especially before eating. Take care with any anaesthetic gel, as they can have active ingredients that can be dangerous for young children. Ask your pharmacist.

Oral herpes (cold sores)

Children can get the herpes simplex virus (HSV) through contact with someone who has a cold sore. The most infectious time is thought to be in the first few days when the cold sore blister is forming. Sometimes, people can pass the virus to others when they have no symptoms. The virus may also be spread via saliva.

The first HSV infection

Most people will not show any symptoms the first time they are infected with HSV. However, for some people, mainly children, the first infection can show as:
  • fever
  • tiredness
  • sores (blisters and ulcers) in and around the mouth
  • swelling
  • pain inside the mouth and on the gums
  • a sore throat
  • swollen neck glands.

Cold sores are repeat infections

Approximately 90 per cent of adults have been infected with the HSV. One third of infected people experience cold sores. These are a reoccurrence of the original HSV infection, not a new infection. Cold sores are most common on the lips, but may also occur inside the mouth, nose, eyes or any part of the face.

Symptoms of cold sores in children

Symptoms in children may include:
  • early signs, which may include tingling, burning or itchiness of the skin
  • small clusters of blisters that quickly break out inside the mouth, or on the gums or lips
  • yellowish ulcers surrounded by a red circle, which develop after the blisters burst
  • red, swollen gums, which bleed when touched
  • fever, feeling unwell, tiredness and irritability.
See your doctor, dentist or other oral health professional, if sores do not heal within two weeks.

Treatment for cold sores in children

There is no cure for the infection, but you can help to reduce pain by giving your child:
  • lots of fluids, preferably water. Dehydration is a risk in small children if it is painful to swallow
  • bland foods such as natural plain yoghurt
  • little or no salty, spicy or acidic foods.
Ask your pharmacist about antiviral creams.

Preventing the spread of cold sores

HSV is transmitted easily. Simple steps that help to reduce its spread include:
  • Avoid touching cold sores, and wash hands thoroughly if a sore is touched.
  • Avoid sharing items such as cups, forks and towels.
  • Take extra care not to touch anywhere around the eyes. A herpes infection in the eyes can be quite serious.
  • Keep children home from childcare or school until a blister stops weeping, if they have trouble following hygiene practices to prevent the spreading the virus.

Tooth abscess

A tooth abscess is caused by an infection around the root of the tooth, normally associated with tooth decay. It appears as a pimple on the gum or as swelling of the face on the side of the affected tooth.

See a doctor, dentist or other oral health professional immediately, if you think your child may have a tooth abscess.


Cellulitis is a bacterial infection that can appear as a redness of the skin, swelling and fever, and has the ability to spread very quickly. If this infection is seen on the face, it can be related to a tooth abscess, where the infection has spread to the deep layers of the skin on the face. Cellulitis on the face is more common in children under the age of three.

See a doctor, dentist or other oral health professional immediately if you notice these symptoms.


A mucocele is a soft, bluish-grey swelling usually on the lower lip. It can be caused by trauma to the lip, often from lip biting.

Mucoceles will often burst and heal by themselves. If they don’t heal, or if they become a problem, see your doctor, dentist or other oral health professional.

Eruption cysts

An eruption cyst is a smooth, bluish, dome-shaped blister that appears on the gum where a tooth is coming through. Usually treatment is not required because the cyst bursts when the tooth breaks through.

Seek advice from a doctor or oral health professional if you think the area may be infected.

Hand, foot and mouth disease

Hand, foot and mouth disease is characterised by painful ulcers in the front of the mouth and small blisters on the hands and feet. A sore throat or mouth, and a minor fever may also be seen.

This disease will heal by itself. Give fluids (mostly water) and soft foods to reduce discomfort. Keep your child at home until the sores have dried to prevent spreading the disease.


Measles first appears as lots of small white spots that look like grains of salt surrounded by inflammation (swelling and redness) on the inside of the cheeks. The white spots appear two to three days before the measles rash shows on the face and body.

Measles can be a serious condition in young children. See your doctor immediately if you think your child might have measles.

Tooth decay

Everybody has the bacteria in their mouth that causes tooth decay. These bacteria feed on sugars from foods and drinks and produce acid which damages the outer surface of the tooth (the enamel). Saliva can repair this damage, but if there is more damage than repair over time, it leaves a cavity or ‘hole’ in the tooth.

Tooth decay is largely preventable. However, one in three children aged five and under who attended Victorian public dental clinics in 2010 and 2011 experienced tooth decay. Around two thirds of this was untreated. Tooth decay remains five times more prevalent than asthma.

Where to get help

  • Your maternal and child health nurse.
  • Community dental clinics:
  • To find your local clinic Tel. 1300 360 054 or search by postcode.
  • The Royal Dental Hospital of Melbourne:
  • General enquiries or to make an appointment Tel. (03) 9341 1000 or 1800 833 039 outside Melbourne metro 8.30 am to 5 pm, Monday to Friday
  • Dental emergencies Tel. 1300 360 054 8.30 am to 9.15 pm, Monday to Friday, 9 am to 9.15 pm, weekends and public holidays
  • Your private dental clinic:
  • Look in the Yellow Pages under ‘Dentists’ or search the ‘Find a Dentist’ search tool on the yellow pages web site.
  • Visit the Australian Dental Association website, and use the ‘Find a Dentist’ search tool.
  • Your doctor

Things to remember

Oral conditions are common in young children. Give water and avoid salty, acidic or spicy foods to ease the pain of mouth ulcers. See your doctor or oral health professional immediately for mouth infections, facial swellings and rashes, or if mouth sores do not heal after two weeks.

More information

Mouth and teeth

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This page has been produced in consultation with and approved by: Dental Health Services Victoria

Last updated: April 2015

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Content on this website is provided for education and information purposes only. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your doctor or other registered health professional. Content has been prepared for Victorian residents and wider Australian audiences, and was accurate at the time of publication. Readers should note that, over time, currency and completeness of the information may change. All users are urged to always seek advice from a registered health care professional for diagnosis and answers to their medical questions.