What is necrotizing fasciitis?

Necrotizing fasciitis is a term that describes a disease condition of rapidly spreading infection, usually located in fascial planes of connective tissue that results in tissue necrosis (dead and/or damaged tissue). Fascial planes are bands of connective tissue that surround muscles, nerves, and blood vessels. Fascial planes can bind structures together as well as allow body structures to slide over each other effectively. The disease occurs infrequently, but it can occur in almost any area of the body. Although many cases have been caused by group A beta-hemolytic streptococci (Streptococcus pyogenes), most investigators now agree that many different bacterial genera and species, either alone or together (polymicrobial infections), can cause this disease. Occasionally, mycotic (fungal) species cause necrotizing fasciitis. Popular publications and the media term necrotizing fasciitis as a "flesh eating" or "skin eating" disease or infection. In addition, the organisms that typically cause necrotizing fasciitis are termed "flesh-eating bacteria" or "flesh-eating parasites" because of the rapid rate with which they can infect and kill human tissue.

Historically, several people described this rapidly advancing condition in the 1840s to 1870s; however, Dr. B. Wilson first termed the condition “necrotizing fasciitis” in 1952. It is likely that the disease had been occurring for many centuries before it was first described in the 1800s. Currently, there are many names that have been used loosely to mean the same disease as necrotizing fasciitis: flesh-eating bacterial infection or flesh-eating disease; suppurative fasciitis; dermal, Meleney, hospital, or Fournier's gangrene; and necrotizing cellulitis. Body regions frequently have the term necrotizing placed before them to describe the initial localization of necrotizing fasciitis (for example, necrotizing colitis, necrotizing arteriolitis), but they all refer to the same disease process in the tissue. Important in understanding necrotizing fasciitis is the fact that whatever the infecting organism(s), once it reaches and grows in connective tissue (fascial planes), the spread of the infection can be so fast (investigators suggest some organisms can progress to involve about 3 centimeters of tissue per hour) that the infection becomes difficult to stop even with both antimicrobial drugs and surgery. Fortunately, this disease is relatively rare; various statistical sources estimate about 500 to 1,500 individuals are reported to have the disease per year in the U.S.

Statistics show mortality (death) rates have been reported as high as 75% for necrotizing fasciitis associated with Fournier's (scrotal) gangrene, but the mortality in patients with the infection in other regions of the body (for example, legs or arms) is about 25%. Patients with necrotizing fasciitis have an ongoing medical emergency that often leads to death or disability if it is not promptly and effectively treated.