What Is The Treatment For Red Rashes On The Scalp?

I have taken my daughter to a dermatologist three times since the age of two, mot recently the only remedy to alleviate her scalp rash/flaky red area was antiobiotics and trimcinoione acetonide cream with oatmeal baths and head n shoulders. Now that the antibiotics ran out her rash is back full fledged. ??What does she have? The derma said maybe acute dermatitis but maybe psoriasis but last time she had impetigo at two?