itchy rash on back

My back started itching about six months ago with small rashes that would come and go, about three months later it it was itching a lot and covered most of my back and on my buttox. I tried sarna anti itch lotion and it seemed to get worse.  I went to emergency and they said it was contact dermatitis and perscribed hydrocortizone cream that did not work and I went back.  The rash was looking a bit different and they thought it was a fungal rash and perscribed atarax, clotrimazole cream usp, 1% and triamcinolone acetonide cream .01% I used that and put vasaline on top of it and it went away.  About three weeks ago it came back the doctor told me it was contact dermatitis and perscribed triamcinolone acetonide .025% lotion it got worse.  I am thinking it is a reaction to one of my medications geodon. I stoped taking it yesterday and went to the emergency room they perscribed prednisone this morning it was feeling better it looked about the same but the itching and burning was better.  I was told not to put anything on it even if it gets dry well it's getting dry and starting to get itchy again. I am waiting to see a dermatologist. Does anyone know what this might be?