55 y/o female with Grover's Disease

I was recently diagnosed with Grover's disease although I am not convinced it's proper diagnosis. The rash coincides with the purchase of a new polyurethane mattress. However, I have since moved to another room and it persists... so it could be coincidence. It started on my temples as little bumps that had an INTENSE ITCH and then they slowly progressed over a couple months down the back of my head, then neck, upper, back, then low back and around to my stomach with a few small outbreaks on my elbows. I was superscribed prednisone which was a god send. It stopped the itching completely and the bumps almost completely disappeared. Until I ran the course, and it all came back with a vengeance! The itching is awful! I can't sleep. No antihistamines work, no over the counter creams work. It's only been about three months since this all started and I can't imagine living like this for years! I have had custody of my 16 month old grand daughter since her birth so I can't afford to lose any more sleep! I need HELP!