What Causes Warm, Itching And Smooth Rash With Cough?

I have hot, itching, smooth rash with a cough and extreme shortness of breath at time. The rash will fade sometimes but is never completely gone. It is unbearable. I am taking prednisone and Benadryl and just spent 3 days in the hospital with this and the physicains haven t been able to diagnose the problem. Please help