Necrotising Fasciitis
Key points
Definition & Overview
Rare, aggressive soft tissue infection involving fascia & subcutaneous tissue.
Rapid progression → tissue necrosis, sepsis, multi-organ failure.
Paediatric incidence: 0.8 per 100,000/year - higher in children < 5 years of age
Paediatric mortality: 0–15% (lower than adults).
Aetiology & Classification
Type I (Polymicrobial):
Less common in children
More often in infants < 1 year of age
Immunocompromised or postsurgical patients
Type II (Monomicrobial):
Most common in children.
Often caused by Group A Streptococcus (Streptococcus pyogenes) or Staphylococcus aureus
Risk Factors
• Varicella infection (most frequent trigger).
• Minor trauma (injections, scratches, insect bites).
• Penetrating injuries, omphalitis, dental abscess.
• Immunocompromised state (malignancy, neutropenia).
• Recent surgery or BCG vaccination.
Clinical Features
May become critically ill within first 24-48 hours.
Can progress as fast as 1 inch / hour
Forms
Necrotising fasciitis
Fournier's gangrene
Local Signs
Erythema (58–95%)
Induration, swelling (48–100%)
Skin discoloration → bullae → necrosis
Pain disproportionate to appearance
Crepitus (gas in tissues) – late finding
Systemic Signs
Fever (77–100%)
Tachycardia, hypotension
Tachypnoea, altered mental state
Septic shock, SIRS (seen in >65% of cases)
Common Sites
Children: Trunk > Extremities > Head/Neck
Adults: Extremities most common
Neonates: Umbilicus (omphalitis), perineum
Microbiology
Group A Streptococcus (GAS, Streptococcus pyogenes) – most common (≈45%)
Staphylococcus aureus (including MRSA)
Gram-negative organisms - Pseudomonas aeruginosa, E. coli
Polymicrobial in ~17%
Rare: anaerobes, fungi (Zygomycetes)
Diagnosis
Clinical suspicion is key — early signs are non-specific!
Labs: The Pediatric- LRINEC score has been proposed - CRP > 20 and Sodium < 135 had a specificity of 95%
Imaging
CT shows gas in tissue planes, fascial oedema (should not wait for CT if high clinical suspicion!)
Managment
Surgical
Urgent wide debridement — do not delay!
Repeat debridement often needed
Skin grafting required in ~50% of cases
Flaps occasionally used
Medical
Empiric IV antibiotics - Adjust based on cultures
IVIG in cases with streptococcal toxic shock
Supportive care in PICU: fluids, vasopressors, transfusions
Exam Pearls & High-Yield Points
• Pain out of proportion is a key early clue
• Suspect in febrile child with pain + swelling + erythema
• Post-varicella or trauma = red flag context
• Don't delay surgery for imaging if suspicion is high
• Clindamycin suppresses streptococcal toxin production
• Skin findings (bullae, necrosis) = late signs
• Skin grafts often required post-debridement
• Early diagnosis and debridement = lifesaving
Page edited by Mr Mahmoud Abdelbary MSc, MRCS August 2025
Page edited by Mrs Charnjit Seehra BSc August 2025
References
Zundel S, Lemaréchal A, Kaiser P, Szavay P. Diagnosis and Treatment of Pediatric Necrotizing Fasciitis: A Systematic Review of the Literature. Eur J Pediatr Surg. 2017 Apr;27(2):127-137. doi: 10.1055/s-0036-1584531. Epub 2016 Jul 5. PMID: 27380058.
Schröder A, Gerin A, Firth GB, Hoffmann KS, Grieve A, Oetzmann von Sochaczewski C. A systematic review of necrotising fasciitis in children from its first description in 1930 to 2018. BMC Infect Dis. 2019 Apr 11;19(1):317. doi: 10.1186/s12879-019-3941-3. Erratum in: BMC Infect Dis. 2019 May 27;19(1):469. doi: 10.1186/s12879-019-4003-6. PMID: 30975101; PMCID: PMC6458701.
Eneli I, Davies HD. Epidemiology and outcome of necrotizing fasciitis in children: an active surveillance study of the Canadian Paediatric Surveillance Program. J Pediatr. 2007 Jul;151(1):79-84, 84.e1. doi: 10.1016/j.jpeds.2007.02.019. PMID: 17586195.
VanderMeulen H, Pernica JM, Roy M, Kam AJ. A 10-Year Review of Necrotizing Fasciitis in the Pediatric Population: Delays to Diagnosis and Management. Clin Pediatr (Phila). 2017 Jun;56(7):627-633. doi: 10.1177/0009922816667314. Epub 2016 Sep 23. PMID: 27663964.
Wang JM, Lim HK. Necrotizing fasciitis: eight-year experience and literature review. Braz J Infect Dis. 2014 Mar-Apr;18(2):137-43. doi: 10.1016/j.bjid.2013.08.003. Epub 2013 Nov 22. PMID: 24275377; PMCID: PMC9427441.