 [ Symptoms ] what causes diaper rash and how is it treated [ Disease ] any irritation of the skin in the diaper area can be considered a diaper rash they are extremely common in babies especially those who have loose stools or who have very wet diapers such as infants over 9 months changes in a child is diet can also cause the stool to irritate a baby is skin even if she is changed right away if the baby is not fussy it is likely not a serious rash and will probably go away after a few days of using a diaper cream or ointment if a baby has a fever develops sores in the diaper area has bleeding or pus from the skin has a rash for longer than a few days or seems very uncomfortable it is important to have her checked out by the pediatrician