My Son Has Been Experiencing A Very Itchy Butt Crack

My son has been experiencing a very itchy butt crack for weeks now. There are round red areas. He has gone to the ER as the itching was driving him mad where they prescribed an anti fungal. He experienced no relief. In desperation he has started using bleach wipes that he is rubbing on the affected area and then applying Vaseline. This is providing some relief. His buttocks also sweat terribly. Can you help him?