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Baby with thrush Children's Wisconsin

What are those spots on my baby’s lips, tongue and mouth?


It’s a fact of life — babies get fussy. And for parents, determining the cause of the sudden change in demeanor takes time and practice. Sometimes the cause of the fussiness is obvious — baby is hungry or needs a diaper change. But sometimes, the fussiness isn’t as clear cut.  

Fussiness and irritability can be caused by a number of issues. One common cause is a condition called oral thrush. Parents may notice white spots they can’t seem to clear out of their baby’s mouth. Often, these concerns are accompanied by feeding problems with their baby. So when I hear this from parents, I’ll look for thick, white patches in the baby’s mouth, cheeks, gums, tongue, and even tonsils. The white spots are signs of a yeast overgrowth called oral thrush and sometimes can cause discomfort when feeding.

Let’s talk about what thrush is and what you can do for it. 

What is oral thrush? 

Our bodies naturally carry germs and while some germs cause no problems, others do, like thrush. Oral thrush is a very common yeast infection in babies. The yeast thrives in warm, moist areas, and the baby's mouth is a perfect place for a yeast infection. It causes irritation in and around a baby's mouth. It is formally called oral candidiasis and often affects babies as their immune systems aren’t fully developed yet. It looks like thick white patches on their tongue, inside of cheeks, roof of the mouth or gums. You cannot wipe these patches off. Infants with thrush can have feeding problems because of discomfort in the affected area. 

Diaper rash is also a form of yeast or candidiasis and my colleague Stephanie Olson, MD, wrote a great blog about that. You can read it here.

Symptoms of oral thrush in a baby include:

  • White, velvety patches in the mouth and on the tongue

  • Wiping the spots may cause bleeding

  • Redness in the mouth

  • Fussiness

  • Refusing to nurse because of soreness

How is oral thrush treated?

If you think your baby may have thrush, schedule an appointment with your child’s pediatrician. Some cases go away without medical treatment within a week or two, but some doctors may prescribe an antifungal solution. This medicine is applied four times a day by "painting" it on the inside of the mouth and tongue with a sponge applicator or cotton swab. The medicine is used until the white spots are completely gone, plus a couple of extra days for complete resolution. I also recommend boiling all pacifiers and bottle nipples daily to ensure the yeast has been killed and won’t reinfect your baby. 

If your baby keeps getting oral thrush, especially if they’re older than 1 year old, talk with your doctor because this might be a sign of another health issue.
Nursing moms beware, too. If you have sores on your nipples, or tenderness or pain during or after nursing, you could have a yeast infection that is being passed onto your baby. Also, if your baby has thrush, they could be passing it onto you. Your baby’s pediatrician will be your best resource for how to approach feeding your baby if you or your baby has thrush. 

Can thrush be prevented?

You can do a few things to help decrease the likelihood of your baby developing thrush. But even with best practices, your baby can still get thrush. Here is what you can do:

  • Clean nipples, pacifiers and bottles well: For babies who are bottle fed, whether it’s formula or pumped breast milk, make sure you’re washing nipples and bottles in hot soapy water or the dishwasher after each use. The hot soapy water will kill the yeast that can cause thrush. 

  • Clean toys: One way babies discover new things as they get to be a little more active is by putting things in their mouths. Make sure you wash toys regularly in hot soapy water. 

Bottom line

Thrush is usually harmless, but it can cause you and your baby some discomfort. If you have any questions about thrush or anything else affecting your baby’s health and wellness, always check in with your pediatrician. We are here to help parents through these fun and exciting times with your baby.