Mouth Ulcers and Sores in Children: A Parent's Guide

A sore in the mouth can make a usually happy child refuse food, drink less and sleep badly. Most mouth sores in children are harmless and heal on their own within one to two weeks. The main job for parents is to keep their child comfortable and drinking, and to know which signs need a doctor.

Common types of mouth sores

Canker sores (aphthous ulcers) Small, round, painful ulcers with a white or yellow centre and a red border, usually on the inside of the lips, cheeks or under the tongue. They are not contagious. Triggers can include minor injury, stress, tiredness or certain foods. They usually heal within 7 to 14 days. Children who get them very often should be checked by a doctor.

Injury ulcers Biting the cheek or lip, a sharp chip of food, a rough tooth edge, or rubbing from braces can all cause a sore spot. After a numbing injection at the dentist, children may chew their numb lip or cheek without feeling it, so watch them until the numbness wears off. For braces, orthodontic wax over the bracket often helps. Tell your dentist about any sharp edge that keeps rubbing.

Hand, foot and mouth disease A common viral infection in young children, especially in nurseries. It often starts with fever and sore throat, followed by small painful blisters or ulcers in the mouth and a rash or blisters on the hands, feet and sometimes the nappy area. It is contagious, so keep your child home while unwell, wash hands often and follow your doctor's advice about returning to nursery or school.

Cold sores (herpes simplex virus) Small, tingly blisters on or around the lips that crust over and heal in about one to two weeks. A child's first infection can sometimes be more severe, with fever, many ulcers inside the mouth and swollen, red, bleeding gums. Cold sores are contagious:

• Avoid kissing others, sharing cups, spoons or towels while a sore is present.
• Adults with a cold sore should not kiss babies. The virus can be very serious for newborns.
• Discourage touching or picking the sore, and wash hands afterwards.
• Seek medical advice promptly if sores spread near the eyes.

Keeping your child comfortable

1. Fluids come first. Offer small sips often: cool water, milk, or ice lollies made from water or milk. A straw may help avoid the sore areas.
2. Soft, bland foods such as yoghurt, labneh, soft rice, mashed potato, soup that has cooled, and smoothies.
3. Avoid acidic, salty, spicy or crunchy foods, like citrus, tomato, crisps and hard bread, which can sting.
4. Keep brushing gently with a soft brush, avoiding the sore itself. A clean mouth heals better.
5. Pain relief: ask your pharmacist or doctor about paracetamol or ibuprofen, and give the correct dose for your child's weight. Never give aspirin to children. Ask the pharmacist before using any mouth gel, as some are not suitable for young children.

When to see a doctor

Please contact your paediatrician if:

• A sore lasts more than two weeks or keeps coming back
• Your child has a high fever, or seems very unwell or unusually sleepy
• Your child is refusing to drink. Young children can become dehydrated quickly. Warning signs include fewer wet nappies or trips to the toilet, a dry mouth, no tears when crying and unusual drowsiness.
• There are many sores along with very swollen, bleeding gums
• Sores are near the eyes, or your baby is under a few months old
• There is a large, unusual or painless sore that doesn't heal

If your child becomes very drowsy, has difficulty breathing or shows signs of severe dehydration, seek emergency care or call an ambulance on 998.

A dentist can help when a rough tooth, broken filling or braces is the cause.