MAYBE ALLERGIE TO THE METAL PART OF YOUR BELT It could be hives. I took a medication that I didn't know I was allergic too and had hives (diagnosed.) It was on my stomach to waist and lighter on my arms. It could also be your laundry detergent or softener you are using on your clothes. Change that to see if this is the cause. Also check out any body lotions you may be using. Usually "Aveeno" (made with oatmeal) is the best for one's skin and has a lower risk of allergies.