Mouth ulcers in babies

Mouth ulcers are a type of sore. They can develop on your baby's mouth, lips, tongue and gums.

Mouth ulcers are also known as canker sores or aphthous ulcers.

Mouth ulcers are common in children. Different types of ulcers may look different, depending on what is causing them.

Most mouth ulcers get better on their own within 2 weeks. If an ulcer does not heal after 2 weeks, it is called a chronic ulcer.

There are many reasons why your baby might develop a mouth ulcer. These can include:

• viral infections, such as herpes simplex virus, hand, foot and mouth disease (caused by certain enteroviruses) or cytomegalovirus (CMV)
• fungal infections
• nutritional deficiencies, including low levels of vitamin B, folic acid, iron or zinc
• side effects from some medicines, such as non-steroidal anti-inflammatory drugs (NSAIDs) and certain antibiotics
• injuries to the mouth, from falls, bumps, or accidentally biting their gums or lips
• other health conditions, such as coeliac disease, Crohn's disease or ulcerative colitis
• sometimes ulcers may appear with no obvious cause

You should take your baby to their doctor if:

• your baby has mouth ulcers and you are worried about their health
• your baby is not drinking enough fluids (water, breastmilk or infant formula) and you are worried they might become dehydrated
• your baby is immunocompromised and has ulcers in their mouth
• you are worried your baby's ulcer is becoming infected (it looks red, raised and filled with pus)
• it seems like your baby is in severe pain

Your baby's doctor can diagnose a mouth ulcer by examining their mouth and asking you about their symptoms and medical history. Sometimes the doctor may take a swab of your baby's ulcer to send to the laboratory.

Treatment for your baby's ulcer includes treating the cause of their ulcer and their symptoms.

Treatment includes:

• hydration — make sure your baby drinks enough fluids, so they do not become dehydrated
• managing your baby's pain — paracetamol, ibuprofen (if your baby is over 3 months of age) or numbing creams that relieve pain
• antiviral medicine if your baby's ulcers are caused by the herpes simplex virus and they are immunocompromised

Try to encourage your baby to drink more fluids. If your baby is less than 6 months old, speak with your baby's doctor about how to safely feed them fluids. Depending on their age, you may be able to offer them jelly, icy poles, oral rehydration solutions, water or milk.

Your baby's doctor or pharmacist can explain which medicine is best for them and how to give it to your baby safely.

Complications from mouth ulcers are rare and can include:

• infection
• dehydration — if your baby is very dehydrated, they may need to go to hospital to receive fluids

If your baby has herpes simplex virus or hand, foot and mouth disease, they can develop very rare heart or neurological (nerve and brain) complications such as meningitis and encephalitis.

• Learn more about oral herpes in children on The Royal Children's Hospital Melbourne website.
• Read about hand, foot and mouth disease at the National Health and Medical Research Council (NHMRC) website.
• Learn how to recognise and manage dehydration in babies on the Sydney Children's Health Network website.
• You can call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available 24 hours a day, 7 days a week.

Looking for information for Aboriginal and/or Torres Strait Islander people?

The Government of Western Australia, Child and Adolescent Health Service has a directory of Aboriginal child health resources for Aboriginal and/or Torres Strait Islander people.

Do you prefer to read in languages other than English?

The NSW Government Multicultural Health Communication Service has translated the hand, foot and mouth disease resource into many community languages.