Gangrene typically affects fingers, toes and limbs in diabetics, according to WebMD. This condition is called dry gangrene and occurs when loss of blood supply causes body tissue to die. If dry gangrene becomes infected, it can spread inward, harming inner organs and muscles.
Hands and feet are most commonly affected in diabetics suffering from dry gangrene. Poor blood circulation causes the tissue to dry up, turn color and then fall off. The color of dry gangrene ranges from brown to purplish-blue to black. If blood flow is blocked to an inner organ, the condition is called internal gangrene. This usually involves organs such as the appendix or colon, explains WebMD.