Gas gangrene

Gas gangrene usually affects deep muscle tissue. As the condition progresses, your skin may become pale and then turn to a gray or purplish-red color. Your skin will have a bubbly appearance and the affected skin may make a crackling sound when you press on it because of the gas within the tissue.

Gas gangrene is usually caused by infection with the bacterium Clostridium perfringens, which develops in an injury or surgical wound that's lacking Blood flow. The bacterial infection produces toxins that release gas and cause tissue..