By Donna Christiano Campisano 

 Medically reviewed by Daniel Combs, MD

Two things can cause a baby’s tongue to appear white: oral thrush and milk residue.

Both are common and can create a thick, white coating on the tongue that looks like cottage cheese. In healthy infants, neither is serious, though thrush can cause some irritation.

This article looks at the causes of a white tongue in babies.

Oral Thrush

Oral thrush can affect anyone. It's most common, though, in very young babies between 1 month and 9 months of age.1 Studies have found it affects up to 37% of infants in the first month of life. It occurs equally in females and males and those born vaginally or through cesarean section.1

Oral thrush occurs in both breastfed and bottle-fed babies. It usually appears on the parts of the mouth involved with sucking. This includes: 

• The tongue

• The outer corners of the mouth

• The inner lips and gums

Causes

Thrush is a yeast infection. It's most often caused by Candida albicans, a fungus that's naturally present in the gut and mouth. Most of the time, the body’s immune system keeps this fungus from growing out of control.

Because babies have immature immune systems, they're more likely to get infections from fungi and bacteria. A baby's mouth is dark, warm, and moist. This is the perfect environment for Candida albicans to flourish.

Babies can also develop oral thrush if they are born vaginally to a mom with an active yeast infection. Babies given antibiotics or steroids can also develop oral thrush. This is because these medicines can kill both disease-causing bacteria and some of the good bacteria that keep yeast in check.

Symptoms

Oral thrush usually appears as creamy, white, slightly raised bumps. It can appear in these areas:

• Tongue

• Inner lips

• Gums

• Roof of the mouth

• Back of the throat

When these bumps merge, they look like a white or sometimes yellowish coating in the mouth.

A baby with thrush may also have cracks in the corners of the mouth. Babies with thrush can be irritable, especially when trying to feed. This is because the patches can sometimes make sucking and swallowing uncomfortable, though not always.

Thrush can’t be scraped or wiped away and may bleed slightly if you try. 

Treatment

Your baby’s doctor can often diagnose thrush just by looking in your baby’s mouth. Treatment will depend on severity.

• Mild cases that aren't affecting your baby’s feeding may not need any treatment and will go away in a week or two.2

• Moderate to severe cases are usually treated with an antifungal medication like Mycostatin (nystatin). This is applied directly to the white patches several times a day with either an applicator or dropper. 

Prolonged sucking can irritate an already sore mouth. If thrush is making your baby uncomfortable, try these things:

• If you’re breastfeeding, limit each feeding to 20 minutes.3

• If you’re bottle-feeding and your baby is resisting, try feeding with a dropper. 

• If your baby takes a pacifier, use it sparingly.

With treatment, oral thrush usually improves in four to five days.3 Call your doctor if your baby:

• Isn’t eating well

• Is particularly fussy

• Develops a fever

Preventing Spread of Thrush

Oral thrush is highly contagious. Take these measures to prevent spread:

• If you’re breastfeeding and your nipples are red, painful, or cracked, see your doctor. You and your baby might be passing the infection back and forth.

• If you’re bottle-feeding, place bottle nipples and pacifiers in the dishwasher. You can also wash with hot, soapy water after each use. 

• Store prepared formula or bottled breast milk in the fridge. This can help prevent yeast growth. 

Similar Conditions

Other oral conditions like Epstein pearls are also common in babies. These are tiny, harmless cysts that are usually white or yellow. They usually appear on the gums or roof of the mouth and not the tongue. 

Milk Residue (Milk Tongue)

Sometimes a white coating on the tongue is something harmless, like residue after a baby nurses or drinks a bottle.

Causes

A young baby’s diet consisting of either breast milk or infant formula can leave a white coating on the tongue after feeding. If your baby is a newborn, this may be even more pronounced. This is because babies younger than 3 months naturally produce less saliva than older babies and children.4

Symptoms

Thrush can affect the whole mouth and even its outside corners, but milk residue only affects the tongue. It’s hard to tell which one your baby has just by looking, but milk residue can be gently scraped away while thrush cannot.

Cleaning Your Baby’s Tongue

After washing and drying your hands, dampen a clean piece of gauze with lukewarm water. Wrap it around your finger and gently wipe your child’s tongue. If the residue comes off easily, your child likely has milk tongue and not thrush.

Treatment

Milk residue doesn’t need treatment. It comes and goes and won’t cause your baby any pain or discomfort. Milk tongue usually goes away as babies develop teeth and start eating solid foods. Saliva production also picks up around this time, which helps rinse the mouth of milk and food particles.

Summary

There are two things that might cause your baby's tongue to turn white: thrush and milk residue. Both are relatively harmless.

Thrush is caused by a fungus. If your baby is healthy and the fungus doesn't seem to be causing discomfort, it doesn't need to be treated. More extensive infections may require anti-fungal medication.

Unlike thrush, milk residue wipes off easily. It may come and go, but will go away permanently as your baby gets older.

Sources

Clair-Brown TT, Schwerer KE, Dogbey GY. Neonatal thrush is not associated with mode of delivery. J Am Board Fam Med. 2018;31(4),537-541. doi:10.3122/jabfm.2018.04.170426

 Nemours. Oral thrush.

Seattle Children’s. Thrush.

Collares EF, Fernandes MIM. The ontogeny of saliva secretion in infants and esophagoprotection. Arq Gastroenterol. 2015;52(2),156-160. doi:10.1590/S0004-28032015000200016

Sachdeva S, Sabir H. Oral Thrush in an Infant: A Case Report with Treatment Modalities. Neonatal and Pediatric Medicine. 2016;1:2. doi:10.4172/pdc.1000107

Center for Disease Control and Prevention. Children’s Oral Health.

American Academy of Family Physicians. Thrush.

Additional Reading

Kaiser Permanente. Newborn rashes and skin conditions.

Mount Sinai. Thrush in newborns.

Nationwide Children’s. Dental: teeth and gum care for infants and toddlers.

By Donna Christiano Campisano
Donna Christiano is an award-winning journalist, specializing in women and children's health issues. She has been published in national consumer magazines and writes frequently for leading health websites.