Symptoms and Complications
Areas affected by gangrene are usually warm and swollen. The skin may be pale at first, but soon turns red or brown and finally greenish-black. Sometimes, a brown fluid forms under the skin, causing large skin bubbles to rise. If clostridia are the cause of the gangrene, the gas produced by the bacteria can be seen bubbling in these pockets. It often smells foul.
The substances produced by the bacteria are highly toxic to human tissue and kill cells ahead of the infection, keeping the oxygen supply low. Unless the infection is stopped, these bacterial toxins soon reach the bloodstream and begin to poison the vital organs (see Toxic Shock), with the kidneys failing first.