What Causes Spreading Rash On Chest?

I have had a rash for 6wks which was initally treated as poison ivy. With 3 rounds of steroids. It has not stopped. I think it is shingles and possibly staph. It is spreading on my chest and hair. I am going to a family doctor tomorrow, Monday, but should I go right to a dermatologist? I have learned that putting an after shower powder with baking soda/cornstarch helps much more than the creams. I am concerned it is a staph infection and would have I to go into a hospital? Thanks