Thrush is a common infection in the mouth of newborns that is caused by a yeast-like organism called Candida albicans. Thrush commonly shows up about 7 to 10 days after birth, and many experts believe that babies get it from their mothers during birth because the organism usually lives in the vagina.
Thrush appears as white spots that look like milk curd and often occurs in areas of the mouth that are cracked from too much sucking (particularly in babies who sleep with a pacifier) and in babies who have recently taken antibiotics. The white spots of thrush may be mistaken for residual milk; however, thrush is not easily scraped off and the spots may bleed when scraped. If the thrush makes your baby's mouth sore and feeding difficult, restrict pacifier use as much as possible and use a cup and spoon to feed her if necessary.
Thrush can be transferred from baby to the mother's breast, and back to baby, which can result in chronic thrush for both. A yeast infection of the nipples can be very painful, causing cracking, redness, burning or itching, and/or flaky, dry skin, and can occasionally spread to the inside of the breast and infect the milk ducts, causing severe shooting pains in the breast during or after breastfeeding.
Mild cases of thrush usually clear up on their own; however, your baby may need a prescription anti-fungal medicine, such as nystatin, so you should call your pediatrician at the first sign of infection. The medicine needs to remain on the rash as long as possible before it is swallowed, so paint it directly on the affected area and don't give your baby anything to eat or drink for at least half an hour afterwards. Because this type of yeast is present in the gastrointestinal tract, your baby may also have a rash on her bottom at the same time as the thrush, for which your pediatrician will probably prescribe a topical nystatin cream or ointment.
To prevent re-infection, wash all bottles, nipples, and pacifiers with hot, soapy water, and then boil them to eliminate yeast from the cracks and crevices. If the yeast is very stubborn and chronic thrush develops, try washing your laundry, dishes, and baby items in water above 122 degrees F, which is hot enough to kill the yeast. Also try microwaving your undergarments and for 5 minutes on high (be sure your bra doesn't contain any metal pieces), or hanging them in the sun (sun kills yeast). White vinegar added to baths or the laundry can also help kill the yeast.
Call your pediatrician if your child refuses to drink, the thrush gets worse during treatment, or it lasts longer than 10 days.