My 3 year old son has a rash that extends from his perineum up to the top of his gluteal crease. It has been present for a little over a week. At first it looked like ringworm , it has rough edges and was slightly raised and red. Now it appears to be peeling and the skin is smooth. It looks excoriated. I though maybe it was a yeast so I was placing lotrimin cream on it, but it is not improving. He tends to try to scratch at times. He has not been consitpated nor has he had loose stools. He is no longer in diapers, he is potty trained. What could this be? I am concerned.