What is this rash and why won't it go away?

[Km2745]

For the past week I have had tiny bumps all over my body.  At first I thought it was just dry winter skin or mild eczema bc I've had that since I was teen on my legs. I even thought it was a side effect from stress or that I was getting sick. I used my heavy moisturizer and steroid cream that my derm gave me. Nothing has helped. I have these tiny itchy bumps on my arm, chest, neck, back, all over my legs, behind my ears, there are even a few on my stomach and back.  I have tried cream given to me by my dermatologist for dry skin, all kinds of moisturizer, even oatmeal baths. While I can soothe the rash for a few hours it remains still in raised little bumps on my skin. What is this and how the hell so I find some relief before I scratch my skin off?!?!