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Home Topics Infectious Diseases Infections A-Z Necrotising fasciitis (NF) General information - Necrotising Fasciitis

General information - Necrotising Fasciitis

Necrotising fasciitis (NF) is a bacterial infection that affects the soft tissue and fascia (a sheet or band of fibrous connective tissue separating or binding together muscles and organs). It can occur following a cut or some other opportunity for the bacteria to enter the body, such as surgery. The bacteria can also enter through weakened skin, like a blister. Sometimes there is no obvious entry point.

NF is a rare but serious condition.  One of the early signs is intense and severe pain which may seem out of proportion to any external signs of infection on the skin. There may be a small cut or scratch on the skin, for example, but the pain will be very bad. As it progresses, fever, diarrhoea and vomiting can develop, with the person eventually falling unconscious as the infection overcomes them. The skin typically becomes a dark violet colour, blisters may form and the tissue underneath begins to die. Without treatment, such as surgery, to remove the affected tissue and antibiotics, NF will progress rapidly and can result in death.

A number of different bacteria can cause NF, including the group A streptococcus which is associated with a particularly severe form of necrotising fasciitis.

It is estimated that in the UK there are approximately 500 cases of necrotising fasciitis per year, with around 70-100 caused by the group A streptococcus.

How do you get it?

Necrotising fasciitis often occurs following a small cut, or other opportunity for the bacteria to enter the body, such as surgery. The bacteria can also enter through weakened skin, like a blister. Sometimes there is no obvious entry point.

The most important cause of NF is group A streptococcus, as this causes the more severe type of necrotising fasciitis. These bacteria are spread through close person-to-person contact, through secretions from the mouth and throat, or from direct skin contact with individuals carrying the organism.

Who is most at risk?

Necrotising fasciitis can affect anyone. People with medical conditions that weaken their immune systems, create skin lesions, or require invasive treatment procedures, including cancer, diabetes mellitus, kidney dialysis, alcohol abuse and chronic heart and lung disease, are at increased risk.

Injecting drug users are also at increased risk of NF due to the entry of the needle into skin, muscle or blood vessels, the likelihood that they will have compromised  immune systems and their sometimes crowded or unhygienic living conditions.

Healthy people can also develop necrotising fasciitis.

The symptoms

There are three stages of symptoms.

Early symptoms (usually within 24 hours) include:

  • The presence of a minor skin trauma, such as a cut
  • Pain in the general area of the injury - not necessarily at the site of the injury but in the same area or limb
  • Pain that is usually disproportionate to the injury and that gradually increases
  • Flu-like symptoms, such as fever
  • Intense thirst, which will develop as the body becomes dehydrated.

The most important early symptom of necrotising fasciitis is a combination of all the above.

  • Advanced symptoms (usually within 3-4 days) include:
  • Swelling of the painful area, accompanied by a rash
  • Large dark blotches, that will turn into blisters and fill up with fluid
  • A mottled, flaky appearance at the trauma site, as the tissue underneath begins to die
  • Diarrhoea and vomiting.

Critical symptoms (usually within 4-5 days) include:

  • Severe fall in blood pressure
  • Toxic shock from the poisons released by the bacteria
  • Unconsciousness as the body weakens.

Diagnosis and treatment

If you have several symptoms you should visit your doctor to rule out the infection. The early signs and symptoms of  NF are not always easy to recognise and, if you are concerned, insist that you are examined.

If necrotising fasciitis is suspected, it will be treated in hospital with intravenous (directly into the vein) antibiotics. Exploratory surgery may  be undertaken and any affected tissue removed. Drugs that raise the blood pressure may be used and, in extreme circumstances, amputation may be necessary to halt the spread of the infection.

There is no vaccine for NF.

The role of the Health Protection Agency

The Health Protection Agency is an independent organisation, set up by the government to protect the public from the health effects of infectious diseases and other hazards to health. The agency identifies, researches and responds to these threats, which include increases in group A streptococcal infection. It gives advice to the public on how to avoid harm, provides data and information to government, and advises people working in healthcare.

For more information

For further information on necrotising fasciitis visit The Lee Sparks NF Foundation http://www.nfsuk

If you have concerns about your health contact NHS Direct on 0845 4647 or visit their website, or see your family doctor.

Reviewed: 23 February 2010

Did you know ...?

Necrotising fasciitis is often called the flesh-eating disease, but this is misleading. The bacteria don't actually consume the flesh - rather, poisons released by the bacteria (these are known as toxins), destroy the skin and muscle.