What Is The Treatment For Skin Rashes On The Breast And Armpit?

I have developed a rash I have had for several weeks now. It started out on the sides of my breasts and then near the arm pit. It would feel like tiny bee stings and if itched would swell quite largely. And when the swelling would calm down a tiny pin hole like red scab would be left behind. It stopped and then it started on my belly and sometimes the rash would appear on my thighs and behind my knees. My doctor things it could be something I am allergic to and gave me a steroid cream to use.

I am hoping it is not scabies. I have also had a couple spots appear on my left arm and on my right foot. I have also had the rash appear on my left thumb but it was a blister that poped and heal and i also got one on my right hand.

What could this be??