A. She may have thrush, a common yeast infection that appears on a baby's lips, tongue, the inside of the cheeks, and the roof of the mouth. Usually it's just a nuisance, but it can irritate the inside of your baby's mouth during feeding. Call your pediatrician to confirm that it's thrush.
Although it's unlikely that your baby would give another infant thrush, there's a chance she could transfer it to your nipples during breastfeeding. If they suddenly become sore -- red, itchy, with a burning sensation, perhaps puffy or flaky -- you may have a yeast infection. Deep, shooting pain around your nipples during or after feedings is also a warning sign. If your baby has thrush and you're nursing, be on the lookout for these symptoms -- you may need treatment too.
Your doctor may prescribe an antifungal solution to paint on the patches of thrush and the rest of the mucous membranes of the mouth and tongue four times a day for ten days. (If you've developed a yeast infection on your nipples, you may be prescribed a similar antifungal cream.)
Thrush can recur, and another course of treatment may be needed. Don't be surprised if a fungal diaper rash appears too; if so, you may be directed to use an over-the-counter antifungal cream in the diaper area.
While your baby has thrush, sterilize bottle nipples or pacifiers by boiling them for a few minutes, and wash any toys your baby chews on. Soap and water is fine, as is the dishwasher -- but there's no need to boil any toys.