It has been described at least since the time of Hippocrates. The term "necrotizing fasciitis" first came into use in 1952. Signs and symptoms
Symptoms may include fever, swelling, and complaints of excessive pain. The initial skin changes are similar to cellulitis or abscess, thus making the diagnosis at early stages difficult. Hardening of the skin and soft tissue and swelling beyond the area of skin changes are commonly present in those with early necrotizing changes. The redness and swelling usually blend into surrounding normal tissues. The overlying skin may appear shiny and tense. Other signs which are more suggestive of necrotizing changes (but present in later stages in 7 to 44% of the cases) are: formation of bullae, bleeding into the skin which is present before skin necrosis (skin turning from red to purple and black due to thrombosis of blood vessels), presence of gas in tissues, and reduced or absent sensation over the skin (due to the necrosis of the underlying nerves). Rapid progression to shock despite antibiotic therapy is another indication of necrotizing fasciitis. Necrotizing changes affecting the groin are known as Fournier gangrene.However, those who are immunocompromised (have cancer, use corticosteroid, on radiotherapy, chemotherapy, HIV/AIDS, or prior organ or bone marrow transplantation) may not show typical symptoms. Immunocompromised persons also have twice the risk of death from necrotizing infections, so higher suspicion should be maintained in this group.
Myonecrotic infections caused by these clostridial species commonly occur in injecting heroin users. Those with clostridial infections typically have severe pain at the wound site, where the wound typically drains foul-smelling blood mixed with serum (serosanguinous discharge). Shock can progress rapidly after initial injury or infection, and once the state of shock is established, the chance of dying exceeds 50%. Another bacterium associated with similar rapid disease progression is group A streptococcal infection (mostly Streptococcus pyogenes). Meanwhile, other bacterial infections require two or more days to become symptomatic.Type II infection: This infection accounts for 20 to 30% of cases, mainly involving the extremities. This mainly involves  Streptococcus pyogenes bacteria, alone or in combination with staphylococcal infections. Both types of bacteria can progress rapidly and manifest as toxic shock syndrome. Streptococcus species produce M protein, which acts as a superantigen, stimulating a massive systemic immune response which is not effective against the bacterial antigen, precipitating shock. Type II infection more commonly affects young, healthy adults with a history of injury.Type III infection: Vibrio vulnificus, a bacterium found in saltwater, is a rare cause of this infection, which occurs through a break in the skin. Disease progression is similar to type II but sometimes with little visible skin changes.Type IV infection: Some authors have described the type IV infection as fungal in nature. Diagnosis
Early diagnosis is difficult, as the disease often looks early on like a simple superficial skin infection.