Necrotizing fasciitis is caused by several kinds of bacteria. Some of these bacteria also cause infections such as strep throat and impetigo . Usually the infections caused by these bacteria are mild. But in rare cases they can cause a more dangerous infection.
You can get necrotizing fasciitis when bacteria enter a wound, such as from an insect bite, a burn, or a cut. You can also get it in:
Wounds that come in contact with ocean water, raw saltwater fish, or raw oysters, including injuries from handling sea animals such as crabs.
An intestinal surgery site, or in tumors or gunshot injuries in the intestines.
A muscle strain or bruise, even if there is no break in the skin.
The bacteria that cause necrotizing fasciitis can be passed from person to person through close contact, such as touching the wound of the infected person. But this rarely happens unless the person who is exposed to the bacteria has an open wound, chickenpox, or an impaired immune system .