Necrotising fasciitis

Necrotising fasciitis is a life-threatening subcutaneous soft-tissue infection that requires a high index of suspicion for diagnosis.

Always suspect necrotising fasciitis in a patient with a rapidly progressing soft-tissue infection and any of the following: severe pain (disproportionate to the clinical findings) or anaesthesia over the site of infection; oedema and erythema (oedema will typically extend beyond the erythema); systemic signs of infection. However, necrotising fasciitis can be easily missed because the patient may present earlier in the disease process with non-specific signs and symptoms.

If you suspect necrotising fasciitis, immediately refer the patient for urgent surgical debridement; do not wait for the results of investigations before referral. Necrotising fasciitis is a clinical diagnosis. However, investigations can support the diagnosis if this is unclear.

Surgical debridement should be repeated as necessary until the patient has no necrotic tissue remaining.

Adjunctive antibiotic therapy and supportive care is crucial. Start intravenous empirical antibiotics as soon as you have obtained blood cultures. Once culture results are available, tailor the antibiotics to target the causative organism.

Necrotising fasciitis is a life-threatening subcutaneous soft-tissue infection that progressively extends to the deep soft tissues including muscle fascia and overlying fat, but not into the underlying muscle. The causal organisms may be aerobic, anaerobic, or mixed flora. Type I necrotising fasciitis is a polymicrobial infection with anaerobes such as Bacteroides, Peptostreptococcus, or Clostridium, and facultative anaerobes such as certain Enterobacterales or non-group A streptococcus.​​​[1]Pasternack MS, Swartz MN. Cellulitis, necrotizing fasciitis, and subcutaneous tissue infections. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett’s principles and practice of infectious diseases. Philadelphia, PA: Elsevier; 2015:1194-215.[2]Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014 Jul 15;59(2):e10-52. https://academic.oup.com/cid/article/59/2/e10/2895845 http://www.ncbi.nlm.nih.gov/pubmed/24973422?tool=bestpractice.com [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 Dec 14;13:58. https://wjes.biomedcentral.com/articles/10.1186/s13017-018-0219-9 http://www.ncbi.nlm.nih.gov/pubmed/30564282?tool=bestpractice.com [4]Sartelli M, Coccolini F, Kluger Y, et al. WSES/GAIS/WSIS/SIS-E/AAST global clinical pathways for patients with skin and soft tissue infections. World J Emerg Surg. 2022 Jan 15;17(1):3. https://www.doi.org/10.1186/s13017-022-00406-2 http://www.ncbi.nlm.nih.gov/pubmed/35033131?tool=bestpractice.com [5]Diab J, Bannan A, Pollitt T. Necrotising fasciitis. BMJ. 2020 Apr 27;369:m1428. http://www.ncbi.nlm.nih.gov/pubmed/32341079?tool=bestpractice.com ​​​​ Type II necrotising fasciitis is a monomicrobial infection, most commonly with Streptococcus pyogenes (group A streptococci) and occasionally Staphylococcus aureus.​[1]Pasternack MS, Swartz MN. Cellulitis, necrotizing fasciitis, and subcutaneous tissue infections. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett’s principles and practice of infectious diseases. Philadelphia, PA: Elsevier; 2015:1194-215.[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 Dec 14;13:58. https://wjes.biomedcentral.com/articles/10.1186/s13017-018-0219-9 http://www.ncbi.nlm.nih.gov/pubmed/30564282?tool=bestpractice.com [4]Sartelli M, Coccolini F, Kluger Y, et al. WSES/GAIS/WSIS/SIS-E/AAST global clinical pathways for patients with skin and soft tissue infections. World J Emerg Surg. 2022 Jan 15;17(1):3. https://www.doi.org/10.1186/s13017-022-00406-2 http://www.ncbi.nlm.nih.gov/pubmed/35033131?tool=bestpractice.com [5]Diab J, Bannan A, Pollitt T. Necrotising fasciitis. BMJ. 2020 Apr 27;369:m1428. http://www.ncbi.nlm.nih.gov/pubmed/32341079?tool=bestpractice.com ​​ ​

Other infectious aetiologies may rarely cause a monomicrobial necrotising infection that may be associated with specific exposures or risk factors. These include freshwater exposure associated with Aeromonas hydrophila, saltwater exposure or consumption of raw oysters associated with Vibrio vulnificus, and recent travel to (or living in) Taiwan, where Klebsiella pneumoniae is a common cause of monomicrobial infection.[6]Cheng NC, Yu YC, Tai HC, et al. Recent trend of necrotizing fasciitis in Taiwan: focus on monomicrobial Klebsiella pneumoniae necrotizing fasciitis. Clin Infect Dis. 2012 Oct;55(7):930-9. https://www.doi.org/10.1093/cid/cis565 http://www.ncbi.nlm.nih.gov/pubmed/22715175?tool=bestpractice.com ​ Rarely, necrotising fasciitis can be caused by fungal pathogens.  

This topic covers the diagnosis and management of necrotising fasciitis in adults only.