Doctors of USC

The infection can start with something as small as bump or a scrape. Sometimes there is no visible laceration at all. Left untreated, it can be fatal in 24 hours.

"The so-called flesh-eating bacteria cause one of the most aggressive and deadliest infections known," says Stephen Schnall, USC associate professor of clinical orthopaedics and chief of the Hand Surgery Service.

Necrotizing fasciitis (decaying flesh) is a form of infection generally caused by group A streptococcus, a variant of the same bug that causes strep throat. The bacterium picks its victims indiscriminately, attacking healthy and sick persons alike.

Even more alarming is the fact that no one knows how necrotizing fasciitis is transmitted, Schnall says. One of his patients was infected from a tiny scratch he got falling from his bike; another woman merely bumped her elbow, he explains.

"It's just somebody's unfortunate luck to get it," he says. The symptoms are abrupt and severe, Schnall explains. There may be swelling and discoloration of the infected area and the skin may feel warm and very tender. Other common symptoms are pain, fever, dizziness, profound weakness and shock.

"I've seen people deteriorate in front of my very eyes," he adds. The rapidly reproducing bacteria release toxins that kill tissue and invade the blood stream, which may cause the patient to go into septic shock.

"The treatment includes early detection but primarily aggressive surgery to cut away all the infected tissues," Schnall says. Blood transfusions may be necessary due to the severity of the disease, he adds.

The best way to avoid a bacterial skin infection is to clean the wounded area well, apply an antibiotic and then a bandage, Schnall says. Consult a doctor immediately if you get a rapidly spreading infection, or any of the symptoms described above.