Necrotising fasciitis is a very rare skin infection, caused by bacteria, which has a devastating effect on the human body. The infection usually begins in an open wound, but often there is no obvious site of entry in a healthy individual. The first symptom is a redness over an area of the skin. This area is often painful, tender and warm to the touch.
People with Necrotising fasciitis feel very ill, may develop a rapid heart rate and suffer from confusion. In severe cases, the infection can cause unconsciousness and ultimately death.
The Lee Sparks NF Foundation also offer a lot of good information about the disease on their website.