Necrotizing soft tissue infections (NSTI) are uncommon infections associated with considerable morbidity and mortality (20%-40%). They are characterized by rapidly progressive necrosis of soft tissue that primarily involves subcutaneous fat and fascia with variable involvement of the overlying skin and muscle. Extensive soft tissue necrosis is often accompanied by systemic toxicity. Establishing the diagnosis in the early stage of the infection can be difficult, which leads to a delay in surgical treatment and a poor outcome. The principles of treatment are early and aggressive surgical debridement, broad spectrum antimicrobial therapy administered empirically and reassessed pending culture and sensitivity results, and intensive care management. We report a case of NSTI of the arm in a 64-year-old female patient caused by group A Streptococcus and Staphylococcus aureus complicated with toxic shock-like syndrome with emphasis on the pathophysiology of toxic shock-like syndrome and treatment modalities. NSTI developed 10 days after a knife cut wound of the thumb. The patient had no significant comorbidity. Treatment included aggressive surgical debridement with removal of necrotic tissue and extensive fasciotomies 24 h of admission, cardiovascular stabilization and monitoring at intensive care unit, and repeat surgical debridement at 72 h of admission. Early triple drug antimicrobial therapy included high-dose clindamycin, which inhibits protein synthesis and bacterial exotoxin production that is responsible for inflammatory response and toxic shock-like syndrome. In addition, the patient received hyperbaric oxygen therapy (8 treatments in total). The above management led to control of the infective process. Prolonged surgical wound care followed by thin split-skin grafting and placement of secondary sutures on day 36 of admission preserved the extremity with good functional and cosmetic result.