I have the same exact problem - and I can't find the answer either! my skin turns red and seems to swell a tad, then i can't stop itching and it sucks. It seems to be worse if it's cold outside. Plus, it happens to my arms sometimes when riding a bike outside on a bumpy road. I used to think it was because I was 10 pounds overweight, but then I went through a period when I was extremely thin and it still happened.