From the Guidelines
Necrotizing fasciitis is characterized by severe pain, systemic toxicity, and signs of deep tissue involvement, including a hard, wooden feel of the subcutaneous tissue, crepitus, bullous lesions, and skin necrosis. The diagnosis of necrotizing fasciitis can be challenging, but certain features suggest involvement of deeper tissues, including:
- Severe pain that seems disproportional to the clinical findings
- 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 1. These signs are critical in distinguishing necrotizing fasciitis from other skin and soft tissue infections, such as cellulitis. The presence of these signs, particularly severe pain and systemic toxicity, should prompt a high index of suspicion for necrotizing fasciitis and prompt further evaluation and treatment 2, 3, 4. In addition to these clinical signs, imaging studies such as CT or MRI may show edema extending along the fascial plane, although the sensitivity and specificity of these imaging studies are not well defined 1, 3. The diagnosis of necrotizing fasciitis is ultimately confirmed by the appearance of the subcutaneous tissues or fascial planes at operation, which may show a swollen and dull gray appearance with stringy areas of necrosis and a thin, brownish exudate 1, 3. It is essential to note that the signs of necrotizing fasciitis can be subtle, and a high index of suspicion is necessary to make a timely diagnosis and initiate appropriate treatment 2, 4. Recent guidelines also emphasize the importance of clinical judgment in the diagnosis of necrotizing fasciitis, as well as the need for prompt surgical intervention and broad-spectrum antibiotic therapy 5.
From the Research
Signs and Symptoms of Necrotizing Fasciitis
The signs of necrotizing fasciitis can be subtle and may not always be present, making diagnosis difficult 6, 7, 8, 9. Some common signs and symptoms include:
- Local pain, fever, and systemic toxicity 7, 8
- Spreading inflammation and necrosis of the fascia, muscles, and subcutaneous fat 6, 8
- Necrosis of the overlying skin 6
- Purpura with or without blister and ulceration accompanied by severe pain and tenderness in the affected skin 10
- Lack of skin inflammatory signs such as redness and heat, which may be a clinical clue to predict the fulminant type 10
Clinical Presentation
The clinical presentation of necrotizing fasciitis can vary, but it is often characterized by:
- Rapid onset of symptoms 6, 8
- Severe pain and tenderness in the affected area 7, 10
- Fever and systemic toxicity 7, 8
- Variable amounts of thrombi and numerous bacteria detected by Gram stain 10
Diagnostic Challenges
Diagnosing necrotizing fasciitis can be challenging due to the lack of specific clinical features in the initial stage of the disease 6. A high index of clinical suspicion is necessary to avert potentially disastrous consequences 8. Definitive diagnosis is often made at surgery by demonstration of a lack of resistance of normally adherent fascia to blunt dissection 7.