Necrotizing fasciitis (NF) represents a rapidly progressive, life-threatening infection involving skin, soft tissue, and deep fascia. An early diagnosis is crucial to treat NF effectively. The disease is generally due to an external trauma that occurs in predisposed patients: the most important risk factor is represented by diabetes mellitus. NF is classified into 3 different subtypes according to bacterial strains responsible: type 1 associated to polymicrobial infection, type 2 NF, generally associated to Streptococcus species, often associated to Staphylococcus aureus and, eventually, Type 3, due to Gram-negative strains, such as Clostridium difficile or Vibrio. NF is usually characterized by the presence of the classic triad of symptoms: local pain, swelling, and erythema. In daily clinical practice immune-compromised or neuropathic diabetic patients present with atypical symptomatology. This explains the high percentage of misdiagnosed cases in the emergency department and, consequently, the worse outcome presented by these patients. Prompt aggressive surgical debridement and antibiotic systemic therapy are the cornerstone of its treatment. These must be associated with an accurate systemic management, consisting in nutritional support, glycemic compensation, and hemodynamic stabilization. Innovative methods, such as negative pressure therapy, once the acute conditions have resolved, can help fasten the surgical wound closure. Prompt management can improve prognosis of patients affected from NF reducing limb loss and saving lives.