Itchy Leg Syndrome

I just finished walking to school and I got the itchy leg syndrome. It was so bad that I stopped in t he middle of the walkway and scratched. Thankfully campus was a little deserted. This has always happened to me when I have attempted to walk as my daily exercise. Immediately upon arriving at the library, I searched for possible reasons why. I think I had done this before, but obviously the information did not stick. There are a number of possibilities: dry skin (doesn't seem to fit my case because I moisturize religously), irration to fabric (a possiblility), irriatation to soap, sweat, blood moving, and (get this) I may have exercise induced anaphylaxis that could kill me. Okay, I think my exercise will be aerobics from now on.