Necrotizing fasciitis attacks the deeper layers of skin and the tissues that lie under the skin, called the fascia. It spreads easily through the tissue that covers the muscles and lies beneath the skin.
The infection affects muscle and fat tissue as the bacteria release toxins; it can result in shock and organ failure.
Necrotizing fasciitis is extremely dangerous, and it has a high fatality rate, between 20 and 80 percent. In the United States, the Centers for Disease Control and Prevention (CDC) note that between 700 and 1,100 cases of necrotizing fasciitis caused by group A streptococcus have been reported every year since 2010.
- It is commonly known as flesh-eating disease.
- Infection starts at the site of a wound, for instance, a major trauma, a wound from surgery, a small cut, a broken bone, or simply a rash.
- With no treatment, the condition can be fatal.
- It is usually caused by group A streptococcus (GAS).
The most common bacterium associated with necrotizing fasciitis is group A streptococcus, but other types of bacteria can lead to this serious condition as well.
The bacteria enter through the skin, via a cut, scrape, abrasion, or contusion. Sometimes, there is no visible wound.
The patient may be exposed to the bacteria through direct contact with a carrier, or the bacteria may already be present on the patient.
Group A streptococcus
Group A streptococcus is the same bacterium that causes "strep throat" or streptococcal pharyngitis. It is also responsible for skin infections, as well as rare, severe illnesses, such as toxic shock syndrome.
There are various strains of the bacteria, some of which are more powerful than others. With the right set of conditions, Group A streptococcus can cause severe damage.
If the bacteria are deep within the tissue, signs of inflammation may not be apparent in the early stages.
As the infection progresses, signs and symptoms will become more apparent. They may include fever and a general feeling of being unwell. It might take 3-4 days for symptoms to appear.
The skin will become red, hot, and blistered, and there will be intense pain in the infected area. Pain out of proportion with the redness around the affected area is a warning sign of necrotizing fasciitis. There may be edema, or swelling, and crackling under the skin.
The patient may also experience:
- diarrhea and vomiting
- skin swells and changes color, turning violet
- areas of tissue turn black and start to die
- intense pain until the necrosis or gangrene kills the nerve endings
After 4-5 days, the person is likely to be extremely ill, as the infection enters the bloodstream. They will have a high temperature and dangerously low blood pressure, and they may lose consciousness. Without treatment, necrotizing fasciitis is fatal.
Necrotizing fasciitis can affect healthy individuals, but some people are at higher risk; these include:
Heavy consumers of alcohol or drugs are more likely to develop necrotizing fasciitis.
- heavy consumers of alcohol or drugs
- people with diabetes
- older adults
- individuals with malnutrition
- people with chronic or severe ill health
- those with a weakened immune system
- patients with peripheral vascular disease
- those who have recently undergone surgery or experienced trauma
- people with obesity
- women in childbirth
Rarely, it may affect children with chicken pox.
Diagnosis and treatment
A physician will diagnose necrotizing fasciitis by examining the tissues. Samples of tissue are sent to a lab for analysis under a microscope. If the physician suspects or diagnoses necrotizing fasciitis, the patient will receive intravenous antibiotic therapy immediately, due to the risk of systemic shock.
Patients will be treated in the intensive care unit (ICU).
Necrotizing fasciitis is a rapidly spreading infection, and it can cause extensive tissue death and damage. Prompt treatment is vital. Early detection minimizes the need for surgical removal of skin and soft tissue, and it reduces the risk of toxic shock.
However, emergency surgery is often needed to remove infected tissue, as this can stop the infection from spreading. In advanced cases, major limb amputation is necessary.
If necrotizing fasciitis starts deep under the skin, it may be some time before a diagnosis is made. The initial diagnosis might be inaccurate.
When the disease spreads into other areas of the body, for example, the bloodstream, this can lead to an overwhelming bacterial infection and death.
A high level of infection and toxicity in the system can cause all the bodily functions to shut down. There may be respiratory failure, heart failure, low blood pressure, and renal failure.
When doctors are confident that the infection has been stopped, the wounds, either from the initial infection or from emergency surgical treatment, will either be closed or allowed to fill in.
The recovery process involves extended physical therapy, and long-term psychological and emotional healing.
A large open wound will normally require skin grafting. Hyperbaric oxygen treatment can be a beneficial supplementary therapy for people with large, open wounds.
Necrotizing fasciitis is potentially fatal, but with prompt medical attention, patients can be treated successfully.
Since the infection mostly occurs in people with wounds due to surgery or injury, appropriate precautions and care should be taken in these circumstances. All wounds, however minor, should be kept thoroughly clean.
Other prevention methods include:
- Spotting signs of infection - such as redness, swelling, inflammation, hot skin, or secretion.
- Good hygiene habits - people should wash their hands with warm water and soap after sneezing, coughing, before preparing meals, after using the restroom, and before eating.
The Centers for Disease Control and Prevention (CDC) state:
"If you're healthy, have a strong immune system, and practice good hygiene and proper wound care, your chances of getting necrotizing fasciitis ('flesh-eating' bacteria) are extremely low."
The CDC's Active Bacterial Core surveillance (ABCs) monitors the incidence of necrotizing fasciitis that is caused by group A strep in the U.S. The incidence in the U.S. does not seem to be increasing, says the CDC.