One source claims that most people who sought medical attention for a sting entered anaphylaxis before or during the medical session, and that deaths from envenomation are primarily related to anaphylactic shock or cardiac arrest. Either way, certainly some venom fractions are immunogenic and some are cardiotoxic to mammals. Deaths have occurred as a result of multiple organ failure, typically after a large number of stings. Sting victims that experience life-threatening organ failure commonly exhibit signs of skin hemorrhaging and necrosis, though in patients without organ failure, these symptoms are very rare. The two likely reasons for skin hemorrhaging and necrosis are an inability to effectively neutralize the venom, or unusually potent venom toxicity for that set of stings. In either case, for a small number of victims, these stings lead to multiple organ injury. While not all such victims displayed lesions or necrosis, a strong correlation existed between the number of stings and the severity of injury. Those who died, on average, were stung 59 times (with a standard error of 12), while those who survived suffered only, on average, 28 stings (with a standard error of four, and a p=0.01).