Clostridial necrotizing infection with multiorgan failure in an unhoused patient following a presumed spider bite

Abstract Spider bites are commonly encountered in medicine and, when recognized early, can often be effectively managed with supportive care or antivenom. However, in rare cases, particularly in individuals with poor living conditions, chronic comorbidities, or immunocompromised states, arachnid envenomation can act as a portal for rare but life-threatening complications. We introduce the case of a 59-year-old male who presented with a presumed spider bite and later developed necrotizing soft tissue infection complicated by compartment syndrome, acute mesenteric ischemia, septic shock, and multiorgan failure, including pulmonary edema, acute kidney injury, and hepatic dysfunction. This case highlights the importance of early recognition and multidisciplinary intervention in medically and socially complex patients, and underscores how structural vulnerability can both increase exposure risk and amplify clinical severity.