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Necrotizing Fasciitis - Types, Risk, Symptoms, Diagnosis and Treatment

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Necrotizing fasciitis also known as flesh-eating disease is a rare bacterial infection. Read the article below to know more.

Medically reviewed by

Dr. Sugreev Singh

Published At March 18, 2022
Reviewed AtJanuary 19, 2024

What Is Necrotizing Fasciitis?

Necrotizing fasciitis is a severe type of skin infection caused by group A beta-hemolytic streptococci (streptococcus pyogenes). Most scientists now agree that various bacterial species can result in necrotizing fasciitis, either alone or together. Sometimes, fungal species can also cause necrotizing fasciitis. It is a rapidly progressing infection that can destroy top skin layers, underlying muscles, and also subcutaneous tissues. Because of this rapid nature, necrotizing fasciitis is also called "flesh-eating" or "skin-eating" infection, and the causative organisms as "flesh-eating bacteria."

Even though this infection is rare, you can get infected even through a tiny cut. If failed to diagnose and treat promptly, it can be fatal. Around 600 and 700 cases of necrotizing fasciitis are reported in the United States every year, and 25 to 30 % of these cases result in death. The mortality rate of necrotizing fasciitis affecting the scrotum is 75 %, but infection in other regions of the body, legs, or arms, is around 25 to 30 %.


What Are the Types of Necrotizing Fasciitis?

Necrotizing fasciitis is divided into the three following types:

  1. Type 1 - Infection caused by more than one type of bacteria or by rare bacterial species such as Vibrio vulnificus or fungus Candida. Commonly occurs after trauma or surgery.

  2. Type 2 - Infection caused by streptococcus bacteria, rarely seen after minor cuts, abrasion, and insect bites.

  3. Type 3 (gas gangrene) - Wounds that get infected with clostridium bacteria.

How Are Flesh-Eating Bacteria Transmitted?

Bacteria that cause necrotizing fasciitis can enter your body through:

  1. Minor cuts.

  2. Surgical incision.

  3. Any other injury.

  4. Burns.

  5. Insect bites.

  6. Abrasions.

Sometimes, the infection can start without any apparent cause. But once it starts spreading, it rapidly destroys skin, muscle, and fat underneath. Various types of bacteria cause necrotizing fasciitis, and the most common type is group A streptococcus. But, other bacteria that can cause necrotizing fasciitis are Aeromonas hydrophila, Escherichia coli, Clostridium, Klebsiella, and Staphylococcus aureus.

Risk Factors:

The following conditions can increase your risk of getting infected with necrotizing fasciitis:

  1. A weakened immune system.

  2. Alcohol and substance abuse.

  3. Chickenpox.

  4. Cancer.

  5. Liver cirrhosis (liver scarring).

  6. Diabetes.

  7. Heart valve diseases.

  8. Chronic kidney disease.

  9. Lung infections, such as tuberculosis.

  10. Use of steroids.

  11. Use of injectable drugs.

What Are the Symptoms of Necrotizing Fasciitis?

Symptoms of necrotizing fasciitis usually appear after 24 hours of the entry of bacteria into the body. If the bacteria entered the body through a surgical wound, the patient would develop the following symptoms:

  • Severe pain in the surgical site.

  • Swelling or inflammation.

  • Fever.

  • Nausea.

The other signs and symptoms include:

  • Severe pain after a minor injury, such as a cut, abrasion, or opening.

  • The area around the wound looks red and feels warm.

  • Other flu-like symptoms include nausea, fever, chills, dizziness, diarrhea, malaise, and body pain.

  • Dehydration results in intense thirst.

Signs and symptoms that can develop at the site of infection within three to four days include:

  • Purplish-blue skin rash with swelling.

  • Violet marks that become blisters and are filled with foul-smelling fluid.

  • Black scabs (necrotic scabs).

  • Crackling sensation under the skin due to gas formation.

  • Foul-smelling fluid drains from the wound.

  • Gangrene - the tissues die and become discolored, peel, and flaky.

If left untreated, necrotizing fasciitis can lead to a drastic drop in blood pressure, toxic shock, loss of consciousness, and death.

How Is Necrotizing Fasciitis Diagnosed?

Doctors often diagnose necrotizing fasciitis based on the symptoms. They might conduct various tests to confirm the diagnosis. This might include taking a tissue sample from the affected skin. The causative organism will be isolated from this sample. To look at gas formation in tissues and the extent of the infection, the doctor might suggest Doppler ultrasound, CT (computed tomography) scan, or MRI (magnetic resonance imaging). If needed, the doctor will also suggest:

  1. White blood cell (WBC) counts, which gets elevated in necrotizing fasciitis.

  2. BUN (blood urea nitrogen) and sodium, which are decreased in necrotizing fasciitis.

What Are the Complications of Necrotizing Fasciitis?

Necrotizing fasciitis can lead to:

  1. Sepsis (abnormal body's response to chemicals in the blood due to infection).

  2. Streptococcal toxic shock syndrome (a very serious illness caused by group A streptococcus, where the body goes into shock, resulting in low blood pressure and multiple organ failure).

  3. Loss of limbs.

  4. Severe scarring.

  5. Death.

One out of three people affected with necrotizing fasciitis dies even with treatment.

How Is Necrotizing Fasciitis Treated?

The microorganisms isolated from the tissue sample need to be tested for antibiotic resistance because most bacteria that cause this infection are resistant to multiple drugs.

  • IV (Intravenous) Antibiotics - Once the doctor suspects necrotizing fasciitis, they usually do not wait for a confirmatory diagnosis. The patient is immediately admitted, and IV antibiotics are administered. Most doctors prefer multiple antibiotics to be started at the same time to protect the patient from methicillin-resistant staphylococcus aureus (MRSA) and infection with multiple bacteria.

  • Antibiotic Susceptibility Tests - These tests are done on microorganisms isolated from the patient. This will help choose the antibiotics that will be most effective against the infection.

  • Surgical Drainage and Debridement - A surgeon will drain the pus and fluid from the infection site, and if needed, all the necrotic tissue will be removed.

  • Vacuum Dressings - A controlled negative pressure is applied to the wound to stimulate granulation tissue formation and wound healing.

  • Hyperbaric Oxygen Therapy - Here, a specialized chamber is used to give oxygen to the patient under pressure. Oxygen can stop the growth of anaerobic bacteria and promote tissue healing. When done along with surgical treatment and antibiotics, this therapy has shown to reduce mortality by 10 % to 20 %.

  • Skin Grafting - In cases where there is extensive damage to the skin, normal tissue from some part of the body is grafted on to the damaged part.

  • Amputation - When there is extensive damage to the limbs, amputation might be needed to stop the spread of the infection.

Multiple organ failure (heart, kidney, liver) and sepsis need to be treated aggressively to improve prognosis. The patient might need IV fluids, breathing tubes, and drugs to support the heart.

Can Necrotizing Fasciitis Be Prevented?

As a person with necrotizing fasciitis cannot spread the infection to other individuals, preventive antibiotics are not given to close contacts. There are no vaccines available to prevent infection with group A streptococcus,and the only way to protect ourselves is by good wound care.

  1. Make it a point to clean all minor cuts and wounds with soap and water.

  2. Always cover an open wound with dry bandages after you properly clean it.

  3. If the wound is too deep, consult a doctor immediately.

  4. And if you have any open injury, avoid using hot tubs, swimming pools, and rivers or lakes.

For more information on necrotizing fasciitis, you can consult an online doctor.

Frequently Asked Questions


Is Necrotizing Fasciitis Curable?

Necrotizing fasciitis is an unusual bacterial illness that spreads rapidly throughout the body and causes death. Accurate diagnosis, fast antibiotic therapy, and timely surgery are critical for eradicating this disease.


Where Can You Contract Necrotizing Fasciitis?

Necrotizing fasciitis most commonly affects the lower extremities (limbs, toes, feet, and fingers) and is usually seen in diabetic patients. Rarely, the genitals and the head and neck regions are also affected by necrotizing fasciitis.


How Does Necrotizing Fasciitis Spread?

The most common cause of necrotizing fasciitis is bacteria entering the body through a skin break, such as a cut, scrape, burn, insect bite, or wound puncture.


Who Is Predisposed to Necrotizing Fasciitis?

Streptococcal necrotizing fasciitis can affect healthy people. However, it is usually observed either systemically or locally in immunocompromised patients. These individuals often have underlying medical conditions, such as diabetes, peripheral vascular disease, or malignancy.


What Is the Most Commonest Route of Entry for Necrotizing Fasciitis?

The most prevalent route for bacteria to enter the body is a cut in the skin, but it can also occur if the patient suffers from a trauma that does not break the skin. Bacteria can invade the skin in the following ways: Cuts, scratches, and burns are all possibilities. Insect stings.


How Does Necrotizing Skin Appear?

The skin may appear pale initially, but it rapidly turns red or bronze, is warm to the touch, and occasionally shows swelling. Later, the skin becomes violet, frequently forming huge fluid-filled blisters (bullae).


Which Medication Induces Necrotizing Fasciitis?

Jardiance can cause necrotizing fasciitis of the perineum (Fournier's gangrene), which is an unusual adverse effect. This is an uncommon, potentially fatal illness caused by bacteria penetrating the layer of tissue immediately beneath the skin in the perineum, which is the area between the anus and the scrotum in men and the anus and the vulva in women.


What Are the Antibiotics Used to Treat Necrotizing Fasciitis?

The first line of drugs for the treatment of necrotizing fasciitis is Ampicillin or Ampicillin-Sulbactam coupled with Metronidazole or Clindamycin. Anaerobic coverage is crucial for type 1 infection; effective antimicrobials include Metronidazole, Clindamycin, and Carbapenems (imipenems).


Can Necrotizing Fasciitis Be Causedcause by Foods?

Yes. People are usually infected with bacteria and viruses after consuming raw or undercooked seafood, especially oysters. Others contact the bacteria through open wounds and swimming in contaminated waters. Vibrio infection can induce necrotizing fasciitis in rare circumstances.


Is It Possible to Detect Necrotizing Fasciitis with a Blood Test?

Yes. Diagnosis is frequently missed due to a lack of indicators and a low index of suspicion.  With a statistically good link between the LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis)  score and a genuine diagnosis of necrotizing fasciitis, the LRINEC score is important as a clinical determinant in the diagnosis and surgical treatment of patients with necrotizing fasciitis.


Which Age Group of People Are Mostly Affected by Necrotising Fasciitis?

A patient infected with necrotizing fasciitis is usually between the ages of 38 and 44. This condition is common in children.


What Surgery Is Done for Necrotizing Fasciitis?

The primary aspects of surgical therapy are aggressive surgical debridement, necrosectomy (removal of dead tissues), and fasciotomy (relief of acute compartment syndrome). For optimal therapy, only surgical debridement is necessary. Depending on the clinical course and the patient's overall state, debridement is usually repeated within the next 24 hours or later.


Can We Identify Necrotizing Fasciitis by Smell?

Yes. The dark, foul-smelling necrotic fascia that does not flow when incised may be noticed in the final stages.


How Is Necrosis Treated?

Avascular necrosis has no treatment, but if identified early with X-rays or an MRI, nonsurgical therapies such as activity restriction, anti-inflammatory drugs, injections, and physiotherapy may delay its spread. Because avascular necrosis is a progressive disease, surgery is usually needed.


How Do You Get Rid of Necrotizing?

Antibiotics and surgery are usually the first lines of defense when a doctor believes the patient has necrotizing fasciitis. Necrotizing fasciitis is treated with intravenous antibiotics.
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Dr. Sugreev Singh
Dr. Sugreev Singh

Internal Medicine


necrotizing fasciitis
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