Rare Diseases: Necrotizing Fasciitis
This particular form of strep infection usually starts at an area of trivial skin injury - a bruise, scrape, or small cut. The area becomes reddened and hot to the touch as the infection begins, but over 2-3 days the infected tissue begins to die (necrotize). The skin will gradually darken to purplish or black, and large, blood-filled blisters called bullae will begin to form. The below photo from UCSD med school illustrates both the appearance of skin infected with necrotizing fasciitis and the blood-filled bullae.
Left untreated, this infection can quickly march over enormous areas of the body and lead to death in a matter of a couple of days. Treatment involves surgically removing all dead and infected tissue in a process called debridement (de-breed-ment), which usually leaves the muscle layer intact and simply removes all the superficial tissue and skin in the affected region and for a clear margin around the lesion. If the infection continues to spread over limbs after attempts to debride, amputation may be life saving.
Both the infection itself and the treatment are horrendously painful. The lady in the photo above would likely have all the skin stripped off her leg from below the knee to the crotch if she wants to live, after which she'll look like she's been partially dissected until after skin grafts are applied. Meanwhile, not having skin is a huge risk for other types of infections. Recovery is likely to be a long process, involving physical therapy and plastic surgery and lots and lots of medications.
While very rare, the Centers for Disease Control reports that there are fewer than 1000 cases a year in the US. Even with quick treatment, death occurs in many cases. Some names you may recognize of individuals who have been infected or died from Group A Strep necrotizing fasciitis include Jim Henson of muppet fame, and Melvin Franklin of The Tempations.
For more information, see these articles from:
-- The Centers for Disease Control though this article discusses all invasive forms of Group A Strep together, not just Necrotizing Fasciitis.