Causes

Causes of gangrene include:

• Lack of blood supply. Your blood provides oxygen and nutrients to your body. It also provides your immune system with antibodies to ward off infections. Without a proper blood supply, your cells can't survive, and your tissue decays.
• Infection. An untreated bacterial infection can cause gangrene.
• Traumatic injury. Gunshot wounds or crushing injuries from car crashes can cause open wounds that let bacteria into the body. If the bacteria infect tissues and remain untreated, gangrene can occur.

Types of gangrene

• Dry gangrene. This type of gangrene involves dry and shriveled skin that looks brown to purplish blue or black. Dry gangrene may develop slowly. It occurs most commonly in people who have diabetes or blood vessel disease, such as atherosclerosis.

• Wet gangrene. Gangrene is referred to as wet if there's a bacterial infection in the affected tissue. Swelling, blistering and a wet appearance are common features of wet gangrene.

  Wet gangrene may develop after a severe burn, frostbite or injury. It often occurs in people with diabetes who unknowingly injure a toe or foot. Wet gangrene needs to be treated immediately because it spreads quickly and can be deadly.

• Gas gangrene. Gas gangrene typically affects deep muscle tissue. If you have gas gangrene, the surface of your skin may look normal at first.

  As the condition worsens, your skin may become pale and then turn gray or purplish red. The skin may look bubbly and may make a crackling sound when you press on it because of the gas within the tissue.

  Gas gangrene is most commonly caused by infection with a bacterium called Clostridium perfringens. Bacteria gather in an injury or surgical wound that has no blood supply. The bacterial infection produces toxins that release gas and cause tissue death. Like wet gangrene, gas gangrene is a life-threatening condition.

• Internal gangrene. Gangrene that affects one or more of your organs, such as your intestines, gallbladder or appendix, is called internal gangrene. This type of gangrene occurs when blood flow to an internal organ is blocked — for example, when your intestines bulge through a weakened area of muscle in your stomach area (hernia) and become twisted.

  Left untreated, internal gangrene can be deadly.

• Fournier's gangrene. Fournier's gangrene involves the genital organs. Men are more often affected, but women also can develop this type of gangrene. An infection in the genital area or urinary tract causes this type of gangrene.
• Meleney's gangrene. This rare type of gangrene — also called progressive bacterial synergistic gangrene — is usually a complication of surgery. People with Meleney's gangrene develop painful skin lesions one to two weeks after their operations.