Diaper rash is found on the skin under a diaper. It is caused by several factors, including microorganisms (that can sometimes spread to other parts of the body if conditions are favorable), excessive moisture and warmth, or happen when the skin is already irritated. When conditions are right and precautions are not taken, such infections may also spread from child to child.

Diaper rash is often unavoidable. By far the most common cause is the constant wetness of the baby's tender skin, which...