Diaper rash is one of the most common skin ailments among infants. What causes it? Diaper rash is an inflammatory response that occurs when skin stays in contact with urine or feces for periods of time. Feces produces enzymes that act as skin irritants and directly contribute to skin inflammation and breakdown. That's why it's important to regularly change a baby's diapers and cleanse the diaper area thoroughly. Cleansing helps to remove the fecal enzymes that cause skin irritation and diaper rash. Some moms enjoy the convenience of baby wipes, but there are diaper washes available that you can apply with a soft cloth.