Solution: Necrotizing fasciitis is commonly known as the "flesh eating bacteria" and although it is predominantly caused by Group A Strep, many different organisms can cause this process and it can be a monomicrobial or polymicrobial process. Although there are other possible sources of subcutaneous and retroperitoneal air as seen in this case, it would be rare for any of them to extend over multiple spaces and be as extensive as in this case. So, while other more common causes such as penetrating trauma, perforation of a bowel loop or the esophagus and lung trauma should be considered and evaluated for, when you see subcutaneous air, you have to at least think of this possibility. This process often leads to rapidly overwhelming sepsis and death. The mainstay of treatment is aggressive surgical debridement and intravenous antibiotics to keep the infection from spreading.