What could be wrong if you're itching everywhere but your face?

I constantly itch everywhere but the front part of my face, there is nothing noticably wrong until i start scratching, little bumps start to appear and my skin turns pink after i stop scratching the skin returns to normal color but the bumps stil remain for a while, sometimes longer. I've had chicken poxs and measles and as far as i know I'm not allergic to anything. I don't appear to have dry skin and i still itch after taking a bath/changing clothes/sheets and after making other hygenic efforts. Why am i so itchy? Please help!