If your baby gets diaper rash, it does not mean you are a bad mom or you are doing something wrong. In many cases, the cause of diaper rash is completely out of a parent’s hands. It can be brought on by a number of conditions, including wetness, chafing, a sensitivity to the diaper material, new foods that change the composition of the stool or an infection. Of course, by keeping your baby’s diaper as dry as possible and paying close attention to their skin’s reaction to the diapers, you can greatly lower the chances that a rash will develop. However, a diaper rash can also develop if your baby is taking antibiotics, or even if you are taking antibiotics and breastfeeding.
Antibiotics upset the natural balance of bacteria in the human system. When women take antibiotics, they are at risk for a yeast infection, because of the delicate balance of those bacteria in the vagina. Unfortunately, baby’s are at risk for that same imbalance, and the diaper rash could be a combination of irritation and a basic yeast infection. When women take antibiotics, they usually also take probiotics to restore balance. However, your baby’s pediatrician might not allow that, because it can be harsh on a baby’s stomach. To prevent yeast infections for a baby who is consuming antibiotics, take extra care to keep the diaper clean, fresh, and dry. Always let the skin dry after a cleaning session before the next diaper gets put on, and allow your baby to keep her bare bottom in the fresh air as much as possible without a diaper on. While at home, lay down a waterproof cloth occasionally so that she can play on that in the nude. Giving her as much time in the open air as possible will make a yeast infection less likely.
Source: Anknsha Jain et al: Emerging Fungal Infections Among Children. The Journal of Pharmacy and Bioallied Science. Volume 2 Issue 4 pp. 314-320 October 2010