Mine started about 1.5 weeks after being in a boot for a foot sprain. I have always felt that I might have avoided it if I had not worn the boot. The pain kept getting weirder and more diffuse, but I had never heard of CRPS so I just thought it was that the injury was getting worse from walking in the boot. So then I went to non-weight bearing which of course just made it worse. I saw two podiatrists who never mentioned CRPS. I was diagnosed about 6 weeks after the first symptoms by a neurologist. I definitely think immobilization and using that dang knee scooter that helped mine develop.