Mouth ulcers

Mouth ulcers are common and should clear up on their own within 1 to 2 weeks.

They're rarely a sign of anything serious but may be uncomfortable.

They can be very painful for babies and children and often develop during times of stress. They may prevent your child from eating and drinking.

Check if it's a mouth ulcer

Mouth ulcers are usually small, creamy-white and appear on the:

• inside of the mouth
• lips
• gums
• tongue

The most common type of mouth ulcers are known as canker sores (aphthous ulcers).

You may have more than 1 ulcer at a time and they can change in size.

Mouth ulcers are not contagious. But sometimes they are a symptom of a contagious illness.

Traumatic ulcer

A traumatic ulcer can happen after an injury, such as:

• biting the inside of your cheek
• a rough tooth rubbing against your cheek

A traumatic ulcer usually starts as a sore patch on the inside of the cheek. It gets bigger and turns into a painful yellow crater. It can take up to 2 weeks to heal.

Sign of another infection

If you or your child have several mouth ulcers, this can be a symptom of:

• hand, foot and mouth disease - a contagious illness that also causes a rash on the hands and feet
• oral lichen planus - a condition that causes a white, lacy pattern inside the cheeks
• thrush infection - a fungal infection that can cause white blisters

Cold sores

Cold sores are different to mouth ulcers. Cold sores are white, painful blisters. They appear on the outside of the lip or around the mouth (not inside the mouth). They often begin with a tingling, itching or burning sensation.

Cold sores

Causes of mouth ulcers

Mouth ulcers can be caused by:

• biting the inside of your cheek
• badly fitting dentures, braces, rough fillings or a sharp tooth
• cuts or burns while eating or drinking - for example, hard food or hot drinks
• damaging your gums with a toothbrush or irritating toothpaste
• feeling tired, stressed or anxious

Sometimes the cause is something you cannot always control, such as:

• hormonal changes - such as during pregnancy
• your genes - some families get mouth ulcers more often
• a long-term condition - such as inflammatory bowel disease, coeliac disease or Behçet's disease
• a vitamin B12 deficiency or an iron deficiency
• medicines - including some anti-inflammatories or beta blockers

Treatment for mouth ulcers

Mouth ulcers need time to heal and there is no quick fix.

Avoiding things that irritate your mouth ulcer may help to:

• speed up the healing process
• reduce pain
• reduce the chance of it returning

There are things you can do to treat the ulcer, or stop the ulcer returning.

Treatment from a pharmacist

A pharmacist can recommend a treatment to heal ulcers, prevent infection or reduce pain.

For example:

• an antimicrobial mouthwash
• a painkilling tablet, mouthwash, gel or spray (do not give aspirin to children under 16)

You can buy these without a prescription.

They may not always work, so you may need treatment from your GP or dentist.

Treating mouth ulcers in babies and children

Give your child pain relief medicine such as children's paracetamol if they are in pain. Always follow the instructions on the packet.

Make sure your child is drinking enough fluids, such as water and milk. Try offering them cold drinks through a straw if their mouth is very sore.

Offer them cool, soft foods to eat. Rough foods like toast or cereal flakes might hurt their mouth.

Avoid acidic fruits and fruit juices. These can sting their mouth.

Offer your child frequent breastfeeds. If you are bottle feeding your baby, make sure you are using the correct size bottle teat. This will help to avoid any trauma to the inside of your baby’s mouth.

Treatment from your GP or dentist

Your GP may prescribe stronger medicines to treat severe or infect mouth ulcers or ulcers that will not go away.

If the ulcers keep coming back, your GP may send you or your child for blood tests. This is to see if there is an underlying cause, such as coeliac disease, or being low in vitamins or iron.

Most mouth ulcers are harmless. But a long-lasting mouth ulcer is sometimes a sign of something more serious. It's best to get it checked by a GP or dentist.