Condition
Necrotizing fasciitis of the foot and leg
A rare, fast-spreading infection beneath the skin of the foot or leg that needs emergency surgery.
Medically reviewed by Dr. Efe Ozturk · Last reviewed
Watch: Necrotizing fasciitis of the foot and leg: warning signs and surgery
Read the transcript
Necrotizing fasciitis is a rare, fast-spreading infection that destroys skin, fat and the fascia, the tough layer that wraps the muscles. It needs hospital care, antibiotics and, usually, surgery without delay. If you think it is happening now, call 911 or go to the nearest emergency department. Necrotizing soft-tissue infections spread quickly through the skin, the fat beneath it and the fascia. The infection tends to run along the fascia, which has a poor blood supply. So at first, the skin can look less affected than the tissue underneath. Most cases start out looking like ordinary cellulitis, and the picture can worsen within a few hours. Bacteria usually get in through a break in the skin, such as a cut, insect bite or puncture wound. Conditions that weaken the immune system, such as diabetes or kidney disease, raise the risk. With diabetes, several kinds of bacteria often act together, typically starting in the foot and spreading quickly into the leg. The foot’s compartments connect, which helps infection travel toward the leg. Early on, look for red, warm or swollen skin that spreads quickly, and fever. Severe pain is often far worse than the skin looks, and swelling can extend past the redness. In a more advanced infection, there may be blisters, dark spots, oozing, a crackling feeling under the skin, dizziness or confusion. With diabetes, nerve damage and poor circulation may mask these signs, so don’t wait for pain. This is mainly a clinical diagnosis, made from your symptoms and the examination. In a review of 23 studies, fewer than half of the people who had the infection had a fever. An X-ray found fewer than half of cases, and even a CT scan missed about 1 in 9. Scans should never delay seeing a surgeon or the operation itself. What matters most for survival is early recognition and urgent surgery to remove the dead and infected tissue. In pooled studies, the death rate was 19% when the first operation came within six hours of arrival, and 32% when it came later. The surgeon removes dead tissue back to healthy, living tissue, sparing healthy skin where possible and leaving the wound open. Broad-spectrum antibiotics and support for blood pressure and circulation go alongside surgery. A second look is planned within 12 to 24 hours and repeated until little or no more tissue needs removing. So expect more than one operation. Removing a limb is usually not the first step: an international surgical consensus reserves amputation for late and extreme cases. When circulation is poor, we coordinate with vascular specialists, who perform procedures to restore blood flow. If part of the foot can’t be saved, Dr. Ozturk performs toe and partial foot amputations, keeping as much as possible for walking. Recovery takes time, and after a long hospital stay, many people need months of physical therapy. Once you are home, we can take over your wound care, usually with visits every week or two. We measure the wound, clear away dead tissue, adjust the dressings and fit devices that protect the foot. For the wounds that need more, we offer negative-pressure wound therapy, and skin grafts and local flaps. Call 911 or go to the nearest emergency department right away if redness and swelling spread quickly, especially with severe pain or fever. Don’t wait for an office appointment. With diabetes, call us the same day if a foot wound shows new signs of infection. For a foot wound that isn’t healing, see us within a day or two. Dr. Ozturk, a Foot and Ankle Surgeon board certified in wound care, sees patients in Lyndhurst, Paramus and Millburn. To learn more, visit our website, or call the office to arrange a visit.
General education only; not a substitute for individual medical advice.
What a necrotizing infection is
“Necrotizing” means causing tissue to die. Necrotizing soft-tissue infections are rare, life-threatening infections that spread quickly through the skin, the fat beneath it and the fascia.[1] Necrotizing fasciitis is the name most people know, sometimes called “flesh-eating disease.” Many kinds of bacteria can cause it; group A strep is thought to be the most common.[2] In people with diabetes, several kinds often act together, typically starting in the foot and spreading quickly into the leg.[6,3]
The infection tends to run along the fascia, which has a poor blood supply, so at first the skin can look less affected than the tissue underneath. That can delay the diagnosis.[6] Most cases start out looking like ordinary cellulitis, and the picture can worsen within a few hours.[3]
Who is at risk
Bacteria usually get in through a break in the skin, such as a cut, burn, insect bite, puncture wound or surgical wound. Conditions that weaken the immune system, such as diabetes, kidney disease, cirrhosis or cancer, raise the risk.[2]
With diabetes, a foot wound that is deep, long-standing or keeps coming back is more likely to become infected. The foot’s compartments connect, which helps infection travel toward the leg, and high blood sugar when an infection appears may point to one that is spreading fast.[7] For an open sore, see diabetic foot ulcers and diabetic foot infections.
Warning signs
Early on:
- red, warm or swollen skin that spreads quickly
- fever
- severe pain, including beyond the red area, often far worse than the skin looks
- swelling that extends past the edge of the redness[2,3]
In a more advanced or severe infection:
- blisters, dark or black spots, or skin that changes color
- pus or oozing
- a crackling feeling under the skin (crepitus), or new numbness over the area
- dizziness, tiredness, nausea, a racing heart, low blood pressure or confusion[2,3,7]
An international surgical consensus advises treating any fast-spreading soft-tissue infection as necrotizing from the start.[3] With diabetes, nerve damage and poor circulation may mask the usual signs of infection, so don’t wait for pain.[7]
A red, hot, swollen foot and dark or discolored toes have other, more common causes, but with the signs above, go to the emergency department first.
How it’s diagnosed
This is mainly a clinical diagnosis, made from your symptoms and the examination; a normal blood test or scan does not rule it out.[3,4] An X-ray may show gas deep in the tissues, but in pooled studies it found fewer than half of cases.[7,4] Even a CT scan missed about 1 in 9.[4] Scans should never delay seeing a surgeon or the operation itself.[3] When suspicion is high, early surgical consultation is needed to confirm the diagnosis and treat it.[4]
How surgery saves life and limb
What matters most for survival is early recognition and urgent surgery to remove the dead and infected tissue, alongside broad-spectrum antibiotics and support for blood pressure and circulation.[3] A trauma-surgery guideline recommends the first operation within 12 hours of when the infection is suspected.[1]
The surgeon removes dead tissue back to healthy, living tissue, sparing healthy skin where possible and leaving the wound open. A second look is planned within 12–24 hours and repeated until little or no more tissue needs removing, so expect more than one operation.[3]
With diabetes, the international foot infection guideline calls for an urgent surgical opinion for any necrotizing infection. It adds a vascular specialist when circulation is poor, because infection with poor blood flow sharply raises the risk of poor healing and amputation.[7] We coordinate with vascular specialists, who perform procedures to restore blood flow.
Removing a limb is usually not the first step: the consensus guideline reserves amputation for late and extreme cases.[3] When the infection is very advanced or threatening your life, the surgical team may need to remove more of the limb right away; that decision should not wait.[8,3]
When the infection starts in a diabetic foot ulcer, treatment more often includes removing a toe or part of the foot. In one hospital’s study of 86 surgical patients, that was needed for 8 of the 20 whose infection began in a foot ulcer (40%) and 1 of the 66 others.[8] When part of the foot can’t be saved, Dr. Ozturk performs toe and partial foot amputations, keeping as much of the foot as possible for walking. If a below-knee amputation is ever needed, a vascular or orthopedic surgeon performs it.
Hyperbaric oxygen should never replace or delay surgery.[3] A surgical consensus says it may be considered after surgery, though no randomized trials had tested it.[3] The diabetic foot guideline suggests not using it just to treat a foot infection.[7] Once the infection is under control, if it fits your healing wound, we refer you.
Surgery has limits: even with fast care, this is a serious and sometimes fatal illness. In pooled studies, operating sooner lowered the death rate but did not measurably lower the chance of an amputation.[5]
In an emergency, go to the nearest emergency department; don’t wait for a particular hospital or surgeon. Dr. Ozturk treats necrotizing infections of the foot surgically, removing the infected, dead tissue, and follows you through recovery. He has hospital privileges at Hoboken University Medical Center and Hudson Regional Hospital. For other deep foot infections, see surgery for diabetic foot infections.
Recovery and getting back on your feet
Closing large wounds and regaining function take time. After a long hospital stay, many people need months of physical therapy.[3] Healing can take longer when the infection began in a diabetic foot ulcer. In the study above, 35% of those patients were alive with a healed wound at 90 days, compared with 80% of the others.[8]
Dr. Efe Ozturk, a Foot and Ankle Surgeon, is board certified in wound care (FAPWH). Once you are home, we carry on with your wound care (or take it over if you had surgery elsewhere), usually with visits every week or two. We measure the wound, clear away dead tissue, adjust the dressings and fit devices that protect the foot. For the wounds that need more, we offer negative-pressure wound therapy and skin grafts and local flaps, and Dr. Ozturk performs further foot surgery, such as removing infected bone.
If part of the foot was removed, see problems after a partial foot amputation, and for nerve pain, our sister practice’s page on pain after leg amputation (external site). If, after you have recovered, you are told you need a larger planned amputation, a limb salvage second opinion can help you weigh the options. An amputation the hospital team says is needed to control the infection should never wait for a second opinion.
Lowering your risk
With diabetes, check your feet every day (external site) and keep blood sugar in range, since long-standing high blood sugar may make foot infections more likely.[7] Once an ulcer heals, work on keeping the foot in remission.
When to seek care
References
- 1.Gelbard RB, Ferrada P, Yeh DD, et al. Optimal timing of initial debridement for necrotizing soft tissue infection: A Practice Management Guideline from the Eastern Association for the Surgery of Trauma. J Trauma Acute Care Surg. 2018;85(1):208-214. PubMed 29485428 (external site)
- 2.Centers for Disease Control and Prevention. About Necrotizing Fasciitis. Group A Strep. cdc.gov (external site)
- 3.Sartelli M, Guirao X, Hardcastle TC, et al. 2018 WSES/SIS-E consensus conference: recommendations for the management of skin and soft-tissue infections. World J Emerg Surg. 2018;13:58. PubMed 30564282 (external site)
- 4.Fernando SM, Tran A, Cheng W, et al. Necrotizing Soft Tissue Infection: Diagnostic Accuracy of Physical Examination, Imaging, and LRINEC Score: A Systematic Review and Meta-Analysis. Ann Surg. 2019;269(1):58-65. PubMed 29672405 (external site)
- 5.Nawijn F, Smeeing DPJ, Houwert RM, et al. Time is of the essence when treating necrotizing soft tissue infections: a systematic review and meta-analysis. World J Emerg Surg. 2020;15:4. PubMed 31921330 (external site)
- 6.Wallace HA, Perera TB. Necrotizing Fasciitis. In: StatPearls. StatPearls Publishing; updated 2023. PubMed 28613507 (external site)
- 7.Senneville É, Albalawi Z, van Asten SA, Abbas ZG, Allison G, Aragón-Sánchez J, et al. IWGDF/IDSA guidelines on the diagnosis and treatment of diabetes-related foot infections (IWGDF/IDSA 2023). Diabetes Metab Res Rev. 2024;40(3):e3687. PubMed 37779323 (external site)
- 8.Tang H, Guo W, He J, et al. Diabetic Foot Ulcer-Associated Versus Other Lower-Extremity Necrotising Soft-Tissue Infections: A Retrospective Cohort Study. Int Wound J. 2026;23(9):e71045. PubMed 42788216 (external site)
This page is general health information and isn’t a substitute for advice from a clinician who knows your history. Read our medical disclaimer and how we review content.
Related topics
Condition
Diabetic foot infections
An infection of the skin, deeper tissue or bone of the foot in a person with diabetes, usually starting in a wound.
Treatment
Diabetic foot infection surgery
An operation that drains pus and removes dead and infected tissue from a diabetic foot infection, often in stages, before the wound is closed.
Symptom guide
Red, hot, swollen foot
How infection, active Charcot, gout and a blood clot differ when a foot with diabetes turns red, hot and swollen, and why it needs a call the same day.
Treatment
Limb salvage surgery
Operations that clear infection, remove infected bone, take pressure off ulcers, rebuild collapsed feet and close wounds, with the aim of saving the foot and keeping you walking.