Diaper rash, yeast: Infection in the diaper area caused by a yeast formerly called Monilia and now called Candida. These organisms are part of the germs normally found in various parts of the body and ordinarily do not cause any symptoms.
Certain conditions, such as antibiotic use or excessive moisture, may upset the balance of microbes and allow an overgrowth of Candida. Candida may exacerbate diaper rash and make it much worse, as this yeast grows very readily on damaged skin. The infected skin is usually fiery red with areas that may have a raised red border.