What are the early symptoms of gangrene in the foot?

S&S of foot gangrene. In the early stages, a wound surrounded by redness followed by tissue death with darkened avascular tissue, drainage, air entrapped in the tissues causing a crunching sound with eventual malodorous drainage and red streaks running up the leg followed by fever, sepsis and eventually death may occur in untreated gangrene.
Pain, Purple Skin. Initially, gangrene can be forewarned by pain at rest that may be improved by dangling the foot. The skin color may be purplish or reddened, depending on the severity. As the disease worsens, the skin will turn darker and even become black, dry and hard or else wet and soupy. This stage will require partial or complete amputation. A vascular surgeon may be able to prevent this if treated early.