Why do diabetics wear special socks?
Poor blood sugar control leads to damage in the capillaries, which are essential for healing wounds. Thus, if a diabetic wounds his/her foot even in normal ways (such as a common blister or dry skin cracking around the heel), the simple, trivial wound can eventually become gangrenous and require amputation.
Diabetic socks are a simple way to avoid blisters and cracking. They cost about the same as other socks and can prevent you from becoming an amputee.