rash on right arm ~ again

When I had my daughter 4 years ago I developed a rash on my right arm. A few bumps on my left arm but the majority on the right arm The rash stuck around for about ayear, sometimes itchy but most of the time just visually annoying. It looked like tiny pimples up and down my arm, red around the outside and a small white dot in the middle. I had my son 6 months ago and the rash is back in the same area.  Has been itching me more and more lately and nothing i put on it helps at all.  Any info or suggestions you have for me would be greatly appreciated! Thank you!