A yeast infection that causes velvety, white patches in the mouth

By Carrie Madormo, RN, MPH 

 Medically reviewed by John Carew, MD

Thrush is a common yeast infection in the mouths of babies caused by the fungus Candida. It typically causes white patches in a baby's mouth or tongue. It can also occur in other places, such as the diaper area.

It is not dangerous and doesn't always need to be treated. A healthcare provider can prescribe an anti-fungal medication to help clear up a more severe case.

This article explains more about what causes thrush in babies, whether it can be serious, and what steps to take if a baby’s thrush symptoms aren’t going away.

Reproduced with permission from ©DermNet NZ www.dermnetnz.org 2022.

Signs and Symptoms of Thrush in Babies

Thrush in babies usually appears as white, velvety patches on the tongue and inner cheeks that may bleed when wiped.

It may also cause:

• Redness inside the mouth

• Oral pain

• Loss of taste

• Dry mouth

• Crying or fussiness

• Refusal to feed or use a pacifier due to pain

A white tongue alone does not mean that your baby has thrush. Many babies have white tongues after drinking milk. The white patches from thrush usually cover multiple surfaces in your child’s mouth and cannot be easily wiped away. When you attempt to wipe them away, the sores may bleed. Oral thrush will usually also have a red border around the white patch.1

Thrush in babies doesn't always appear just in the mouth, however. It can also affect the following areas:2

• Fingernails 

• Eyes

• Diaper area (the vagina or groin)

• Skin folds (armpits or folds in the neck)

If the yeast enters a baby’s digestive tract and their stool, it may lead to a yeast infection in the diaper area. If you notice that your baby has a diaper rash in addition to oral symptoms, they may have two yeast infections rather than just one.3

Is Baby Thrush Serious?

Thrush in babies can be a nuisance, but it is not a serious condition.

However, since its symptoms can cause babies to refuse to eat, it may lead to dehydration.

See a healthcare provider about oral thrush in babies if:

• It seems to be causing pain or your baby becomes inconsolable.

• It doesn't seem to be getting better on its own.

• Your baby is refusing to eat.

• You notice a decline in the number of wet diapers.

Causes of Thrush in Babies

Candida albicans is the yeast responsible for thrush in babies. Antibiotic use is the most common reason why this yeast, which is normally present on the body without causing problems, can grow out of control and cause an infection.

A baby could also become infected with the yeast during childbirth.

Since yeast thrives in warm, moist places, a baby's mouth is a perfect place for it to flourish.

Antibiotic Use

As antibiotics kill off harmful bacteria, they kill off healthy bacteria along with it. Thus, the good bacteria that normally keep yeast in check die off, allowing thrush to grow.

This can lead to different types of yeast infections, including a yeast infection of the nipples. Once this happens, it’s likely that the infection will pass on to a nursing baby’s mouth during feedings.3

Likewise, a baby's own use of antibiotics can also cause them to develop thrush that can then get passed along to a nursing person during feedings.

Frequent signs of a yeast infection of the nipples include nipple skin that is darker in color, cracked, and/or sore, as well as pain with breastfeeding.

Childbirth

Though less common, thrush in babies can also occur during vaginal childbirth.

If a parent has a vaginal yeast infection, the yeast can pass on to a baby as it moves through the birth canal and is delivered.

Diagnosis

Fortunately, thrush is quick and simple to diagnose. Most pediatricians can identify it by looking in your baby’s mouth. The velvety, white patches that cannot be wiped away are classic signs of thrush.

Occasionally, your healthcare provider may recommend scraping off a sample of the white patch for lab testing.

If you notice that your baby is getting frequent thrush infections, talk with your pediatrician to find out if further testing is needed. 

How to Treat Baby Thrush

Thrush in babies does not always require treatment and sometimes goes away on its own after a few days. It is still beneficial to have your pediatrician confirm that the sores in your baby’s mouth are caused by thrush and not another infection.

Your pediatrician may prescribe an antifungal medication to treat your child’s infection. This medication can be painted onto the sores in your baby’s mouth. If the mother has a yeast infection on her nipples as well, her healthcare provider will most likely recommend an over-the-counter antifungal cream to be applied directly to the nipples. The healthcare provider could also recommend an oral antifungal prescription such as Diflucan (fluconazole).3 

Most cases of thrush in babies resolve within two weeks of starting treatment.2

Why Thrush Isn't Going Away

If your baby's thrush isn't going away, it could be due to reinfection. This might be the case if the baby is continuously breastfeeding from nipples that have a yeast infection, or is sharing bedding or anything else with someone who also has a thrush infection. It's important that the baby, and anyone with thrush living in the same house as the baby, be treated at the same time to prevent reinfection.4

Preventing Thrush in Babies

Taking a regular probiotic may help prevent thrush and other types of yeast infections. Probiotics help support the good bacteria, which keep yeast growth under control.5

Talk with your pediatrician before beginning a supplement regimen for your infant. If you are breastfeeding, hold off on starting any natural remedies until you’ve talked with your healthcare provider. 

Aside from that, these strategies can help you reduce the risk of infection:

• Thoroughly clean and sterilize anything that goes into your baby’s mouth, such as a pacifier or bottle nipple.

• Change your baby’s diaper often to help prevent a yeast infection in their diaper area.

• If both you and your baby are experiencing a yeast infection at the same time (or think you might be), get an evaluation and have both infections treated right away. If you nurse and only one of you is treated, it’s likely that you will continue to pass the infection back and forth each time you breastfeed. 

Summary

Thrush is a common yeast infection in babies caused by the fungus Candida. It typically looks like white patches on the mouth, cheeks, or tongue. Antibiotic use and childbirth are the two main causes of baby thrush.

Thrush in babies usually isn't serious and the condition may go away on its own. However, you should notify a healthcare provider if your baby seems uncomfortable, is dehydrated, or is refusing to eat. A doctor may prescribe an antifungal cream.

Sources

Seattle Children’s. Thrush.

American Academy of Pediatrics. Thrush and other Candida infections.

MedlinePlus. Thrush in newborns.

Mount Sinai. Thrush in babies.

Matsubara VH, Bandara HM, Mayer MP, Samaranayake LP. Probiotics as antifungals in mucosal candidiasis. Clin Infect Dis. 2016;62(9):1143-53. doi:10.1093/cid/ciw038

Additional Reading

KidsHealth. Oral thrush (for parents).

Lyu X, Zhao C, Yan ZM, Hua H. Efficacy of nystatin for the treatment of oral candidiasis: a systematic review and meta-analysis. Drug Des Devel Ther. 2016 Mar 16;10:1161-71. doi:10.2147/DDDT.S100795

Pankhurst CL. Candidiasis (oropharyngeal). BMJ Clin Evid. 2013 Nov 8;2013:1304.

Vainionpää A, Tuomi J, Kantola S, Anttonen V. Neonatal thrush of newborns: oral candidiasis? Clin Exp Dent Res. 2019;5(5):580-582. doi:10.1002/cre2.213

By Carrie Madormo, RN, MPH
Carrie Madormo, RN, MPH, is a health writer with over a decade of experience working as a registered nurse. She has practiced in a variety of settings including pediatrics, oncology, chronic pain, and public health.