Bad Breath in Babies and Toddlers

When to get help

Fruity-smelling breath with thirst is an emergency. The NHS describes breath that smells fruity, like pear drop sweets or nail polish remover, as a sign of diabetic ketoacidosis (DKA), together with thirst, needing to pee more often, tummy pain, being sick, breathing more deeply than usual, and being tired, sleepy or confused. It says DKA can happen when type 1 diabetes has not yet been diagnosed, particularly in children, and that symptoms usually develop over 24 hours but can come on faster. Call 999 or go to A&E in the UK if a child has these symptoms and no diabetes diagnosis.

A button battery or more than one magnet in the nose is an emergency. Australia's healthdirect says to go straight to an emergency department or call triple zero (000), because button batteries can kill the tissue inside the nose.

Call 999 (in the UK) for the signs of quinsy, an abscess beside the tonsils that the NHS describes as a very rare complication of tonsillitis: a severe sore throat that gets worse quickly, swelling inside the mouth and throat, difficulty speaking, swallowing, opening the mouth or breathing.

See a doctor if you think something is stuck in your child's nose, as healthdirect advises, or if your child is 11 or younger and has sinusitis symptoms such as green or yellow mucus, facial pain and a high temperature: the NHS sends that age group to a GP rather than a pharmacist. See a dentist if bad breath lasts more than a few weeks despite good brushing, or comes with painful, bleeding or swollen gums or toothache.

What causes bad breath in babies and toddlers?

In a baby or toddler, the places to look are the mouth, the nose and the throat. The NHS lists the causes of bad breath as strong-smelling food and drink, problems with the teeth or gums such as gum disease, holes in the teeth or an infection, fasting, and medical conditions including dry mouth, tonsillitis and acid reflux. The NHS page is written mainly for adults; the sections below take the causes that fit young children one at a time.

New teeth and brushing

Once teeth arrive they need cleaning, and the NHS lists problems with teeth or gums among the causes of bad breath. Its advice for children up to 3 is to:

• start brushing as soon as the first milk tooth breaks through, usually at around 6 months;
• brush twice a day for about 2 minutes, last thing at night and one other time;
• use a smear of children's fluoride toothpaste with no less than 1,000ppm fluoride;
• gently brush the gums and behind the teeth, not just the fronts.

The NHS also suggests taking your child to the dentist when the first milk teeth appear, or before they are 12 months old, and NHS dental care for children is free. More on toddler tooth brushing and dental visits, and night feeds and tooth decay for the question of feeding to sleep.

Mouth breathing and morning breath

The NHS pages connect the dots for morning breath. They list breathing through your mouth at night, which can happen with a blocked nose or sleeping with the mouth open, as one of the main causes of a dry mouth, and dry mouth among the causes of bad breath. Dehydration, including from not drinking enough or being ill, is another cause of a dry mouth on the NHS list, which links bad breath to illness even before you look at the throat.

A child who mouth-breathes and snores most nights, even when well, is worth mentioning to a doctor: see toddler snoring and mouth breathing and, for younger babies, baby snoring and sleeping with their mouth open.

Colds, sinusitis and tonsillitis

The NHS lists bad breath among the symptoms of sinusitis, which is common after a cold and usually clears up on its own within 4 weeks. Other signs include a blocked or runny nose, green or yellow mucus, a high temperature and pain or swelling around the cheeks, eyes or forehead. The NHS notes that young children may also be irritable, have difficulty feeding and breathe through their mouth.

Tonsillitis, a common childhood illness, can cause bad breath too. The NHS includes it among the more severe symptoms, with swollen, painful glands in the neck and pus-filled spots or white patches on the tonsils. Symptoms usually go away after 3 to 4 days; see a GP if they have not gone within a week, and get help from NHS 111 straight away for pus-filled spots on the tonsils or a throat so sore your child struggles to eat or drink. Swollen glands that come with a sore throat are covered in swollen lymph nodes in babies.

Smelly discharge from one nostril

Discharge from just one side of the nose, especially if it smells, can be a sign of something stuck up it. KidsHealth NZ lists the signs as pain or itching around the nose, one blocked nostril, discharge from one side that is sometimes smelly or bloody, noisy breathing and bad-smelling breath. Healthdirect says children aged 2 to 5 are the most likely to put objects in their nose, that there are often no symptoms at first, and that the common culprits are beads, buttons, paper, small toys and food such as nuts, seeds and peas.

Do not try to remove an object you cannot see clearly, or when your child is distressed, which is KidsHealth NZ's advice. Healthdirect warns that sniffing could make your child breathe the object in, and that a doctor or nurse can help you with the "parent's kiss", a way of using air pressure to push it out. If you think something may have been swallowed rather than sniffed, see baby swallowed something.

Reflux and a coated tongue

The NHS includes acid reflux among the medical causes of bad breath; for babies, see reflux and posseting. If your baby has a white coating on the tongue, see oral thrush in babies: the NHS lists oral thrush among the causes of a dry mouth.

Frequently asked questions

Why does my toddler have bad breath in the morning?

One common reason is a mouth that dries out overnight. The NHS lists breathing through the mouth at night, often because of a blocked nose, as a main cause of dry mouth, and dry mouth as a cause of bad breath. The NHS advises brushing last thing at night. Snoring most nights when well is worth mentioning to a doctor.

Can a cold cause bad breath in a toddler?

Yes. A blocked nose can lead to mouth breathing and a dry mouth, and the NHS lists bad breath among the symptoms of sinusitis, which often follows a cold. Green or yellow mucus, a high temperature and facial pain point that way. The NHS says a child aged 11 or younger with sinusitis symptoms should see a GP.

Why does my 1 year old have bad breath?

Things to check at this age are new teeth that are not yet brushed thoroughly, a dry mouth from mouth breathing during a cold, and strong-smelling food. The NHS advises brushing from the first tooth, twice a day with a smear of fluoride toothpaste, and a first dental visit before 12 months.

What does it mean if only one nostril smells or runs?

Discharge from one side of the nose that smells bad, sometimes with blood, is a recognised sign of an object stuck in the nose, and KidsHealth NZ lists bad-smelling breath alongside it. Children aged 2 to 5 are most likely to do this, according to healthdirect. Take your child to a doctor rather than trying to remove it yourself.