Rash on torso

I periodically get rashes all over my torso. Mainly on my chesk, shoulder, stomach & neck. It comes and goes, but when I have it it's around for more than a week. It's terribly itchy and I'm at the point that my bra is uncomfortable and so is anything too abrasive. I have been diagnosed with atopical dermitits and I am allergic to Dust mites & molds, I take Clarinex D12 2x's a day for my allergies but this rash persists. I work in a highly stressful environment and find myself scratching while at work. I'm not sure if I'm allergice to something or is it just stress.