In recent years, with the continuous improvement of people’s living standards, the incidence of perianal necrotizing fasciitis has also increased, so many people will ask, what is necrotizing fasciitis? What is the cause of it? What are the symptoms? What is necrotizing fasciitis? Necrotizing fasciitis is a soft tissue infection characterized by widespread and rapid necrosis of subcutaneous tissue and fascia, often accompanied by systemic toxic shock. As early as 1871, the American surgeon Josepoh Jones called the disease “hospital gangrene”; in 1909, Fedden described the disease as “acute infectious gangrene”; later, Mccafferty et al. called the disease In 1924, Meleney named the disease “hemolytic streptococcal gangrene”; in 1952, Wilson suggested that the progressive gangrene of the superficial and deep veins of the subcutaneous tissue be collectively called acute necrotizing fasciitis. Unlike streptococcal necrosis, this disease is a mixed infection of multiple bacteria, chief among which are aerobic bacteria such as Streptococcus pyogenes and Staphylococcus aureus. The infection damages only the subcutaneous tissues and fascia, and it is an important feature that it does not involve the muscle tissue at the site of infection. Symptoms and signs Different pathogenic bacterial infections can have different clinical manifestations. It can manifest as an acute necrotic process or as a chronic recalcitrant underlying lesion. And it is mostly seen in patients with diabetes and renal disease. 1, hemolytic streptococcal gangrene. This disease is a severe acute septic disease caused by Streptococcus haemolyticus, which is considered by some to be a form of gangrenous dysentery. Characterized by a fulminant course, soon appear local redness and pain and large or bloody blisters, with a burning sensation, partly fused into a sheet, blisters easily broken, broken after peeling the necrotic epidermis, revealing a bright red vesicular surface, part of the necrosis deeper formation of gangrene and ulcers. Mostly seen in the extremities. Mostly accompanied by high fever, exhaustion and other systemic symptoms, untimely treatment can be septicemia or shock and death. 2, clostridium or non-clostridium anaerobic cellulitis. Most often occurs in dirty wound sites, especially perianal, abdominal wall, buttocks and lower limbs and other easy to contaminate the site. It is characterized by the sudden appearance of red, swollen and painful skin, which soon develops into a black central plaque, with the black area gradually becoming gangrenous, with fever and chills. The secretions are black and foul-smelling, often containing small droplets of fat. Clostridium perfringens infection has obvious twisted pronunciation and other manifestations of gas gangrene around the lesion, while mixed anaerobic flora infection is absent. 3, Fornier gangrene. It is a severe gangrene that occurs in the male penis, scrotum, perineum and abdominal wall. It may be caused by intestinal bacilli, gram-positive bacteria or anaerobic infections. It is most commonly seen in patients with diabetes mellitus, localized trauma, embedded circumcision, urethral fistula, or after surgery to the genital area. Clinical manifestations are sudden local skin redness and swelling, and many develop into central dark red plaques and ulcers with submerged ulcer margins, plasmacytic exudate on the surface, severe pressure pain, and often fever. How can we respond as patients? The first thing we need to do as patients is “early detection and early treatment”. Because necrotizing fasciitis is extremely fast, once it is detected, we are in a race with the causative agent! Therefore, we must quickly seek medical attention and go to the relevant hospitals and treatment institutions that are capable of dealing with such diseases, and give emergency surgical treatment, a second earlier, the patient’s danger is one point less, the healing is one point faster, so if you find the signs and symptoms described above, you must pay enough attention!