Thrush, Infant and Child

Thrush (oral candidiasis) is a fungal infection caused by yeast (candida) that grows in your baby's mouth. This is a common problem and is easily treated. It is seen most often in babies who have recently taken an antibiotic.

A newborn can get thrush during birth, especially if his or her mother had a vaginal yeast infection during labor and delivery. Symptoms of thrush generally appear 3 to 7 days after birth. Newborns and infants have a new immune system and have not fully developed a healthy balance of bacteria (germs) and fungus in their mouths. Because of this, thrush is common during the first few months of life.

In otherwise healthy toddlers and older children, thrush is usually not contagious. However, a child with a weakened immune system may develop thrush by sharing infected toys or pacifiers with a child who has the infection. A child with thrush may spread the thrush fungus onto anything the child puts in their mouth. Another child may then get thrush by putting the infected object into their mouth.

Mild thrush in infants is usually treated with topical medications until at least 48 hours after the symptoms have gone away.


  • You may notice white patches inside the mouth and on the tongue that look like cottage cheese or milk curds. Thrush is often mistaken for milk or formula. The patches stick to the mouth and tongue and cannot be easily wiped away. When rubbed, the patches may bleed.

  • Thrush can cause mild mouth discomfort.

  • The child may refuse to eat or drink, which can be mistaken for lack of hunger or poor milk supply. If an infant does not eat because of a sore mouth or throat, he or she may act fussy.

  • Diaper rash may develop because the fungus that causes thrush will be in the baby's stool.

  • Thrush may go unnoticed until the nursing mother notices sore, red nipples. She may also have a discomfort or pain in the nipples during and after nursing.


  • Sterilize bottle nipples and pacifiers daily, and keep all prepared bottles and nipples in the refrigerator to decrease the likelihood of yeast growth.

  • Do not reuse a bottle more than an hour after the baby has drunk from it because yeast may have had time to grow on the nipple.

  • Boil for 15 minutes all objects that the baby puts in his or her mouth, or run them through the dishwasher.

  • Change your baby's diaper soon after it is wet. A wet diaper area provides a good place for yeast to grow.

  • Breast-feed your baby if possible. Breast milk contains antibodies that will help build your baby's natural defense (immune) system so he or she can resist infection. If you are breastfeeding, the thrush could cause a yeast infection on your breasts.

  • If your baby is taking antibiotic medication for a different infection, such as an ear infection, rinse his or her mouth out with water after each dose. Antibiotic medications can change the balance of bacteria in the mouth and allow growth of the yeast that causes thrush. Rinsing the mouth with water after taking an antibiotic can prevent disrupting the normal environment in the mouth.


  • The caregiver has prescribed an oral antifungal medication that you should give as directed.

  • If your baby is currently on an antibiotic for another condition, you may have to continue the antifungal medication until that antibiotic is finished or several days beyond. Swab 1 ml of the nystatin to the entire mouth and tongue 4 times a day. Use a nonabsorbent swab to apply the medication. Apply the medicine right after meals or at least 30 minutes before feeding. Continue the medicine for at least 7 days or until all of the thrush has been gone for 3 days.


  • The thrush gets worse during treatment.

  • Your child has an oral temperature above 102° F (38.9° C), not controlled by medicine.

  • Your baby is older than 3 months with a rectal temperature of 102° F (38.9° C) or higher.

  • Your baby is 3 months old or younger with a rectal temperature of 100.4° F (38° C) or higher.