From the Guidelines
Necrotizing fasciitis is characterized by severe pain, disproportionate to clinical findings, along with signs of systemic toxicity, and should be immediately suspected in patients with these symptoms. The diagnosis of necrotizing fasciitis may not be apparent upon first seeing the patient, but certain features can suggest involvement of deeper tissues, including:
- Severe pain that seems disproportional to the clinical findings, as noted in the 2014 update by the Infectious Diseases Society of America 1
- Failure to respond to initial antibiotic therapy
- The hard, wooden feel of the subcutaneous tissue, extending beyond the area of apparent skin involvement
- Systemic toxicity, often with altered mental status
- Edema or tenderness extending beyond the cutaneous erythema
- Crepitus, indicating gas in the tissues
- Bullous lesions
- Skin necrosis or ecchymoses
These signs, particularly severe pain and systemic toxicity, are critical indicators of necrotizing fasciitis, and a high index of suspicion is paramount for early diagnosis and treatment, as emphasized in the guidelines 1. Computed tomography (CT) or magnetic resonance imaging (MRI) may show edema extending along the fascial plane, but clinical judgment is the most important element in diagnosis, and these imaging studies should not delay definitive diagnosis and treatment. The most important diagnostic feature of necrotizing fasciitis is the appearance of the subcutaneous tissues or fascial planes at operation, which typically shows swollen and dull gray fascia with stringy areas of necrosis and a thin, brownish exudate. Prompt recognition and treatment of necrotizing fasciitis are crucial to prevent morbidity, mortality, and to improve quality of life, and should be based on clinical judgment and suspicion, rather than relying solely on imaging studies or laboratory tests 1.
From the Research
Obvious Signs of Necrotizing Fasciitis
The obvious signs of necrotizing fasciitis include:
- Local pain and tenderness, which was the most common symptom in 90.3% of patients 2
- Spreading inflammation and necrosis starting from the fascia, muscles, and subcutaneous fat, with subsequent necrosis of the overlying skin 3
- Septic shock, which occurred in 12.9% of patients and strongly correlated with mortality 2
- Thickening of the deep fasciae due to fluid accumulation and reactive hyperemia, best seen on magnetic resonance imaging 4
- The presence of gas within the necrotized fasciae, which is characteristic but may be lacking 4
Clinical Presentation
The clinical presentation of necrotizing fasciitis can be non-specific, making early diagnosis challenging:
- The disease often presents with subtle and rapid onset of symptoms 3
- It can be underestimated or confused with cellulitis or abscess in the initial stages 3
- A high index of clinical suspicion is required for early diagnosis 3, 2, 5
Laboratory and Imaging Findings
Laboratory and imaging findings can help support the diagnosis of necrotizing fasciitis: