What are the symptoms of necrotizing fasciitis?

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Last updated: April 9, 2025View editorial policy

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From the Guidelines

Necrotizing fasciitis is characterized by severe pain disproportionate to the visible skin changes, along with other symptoms such as failure to respond to initial antibiotic therapy, systemic toxicity, and skin necrosis or ecchymoses, as outlined in the 2014 update by the Infectious Diseases Society of America 1. The symptoms of necrotizing fasciitis can be subtle at first, but they progress rapidly. Key symptoms include:

  • Severe pain that seems disproportionate to the clinical findings
  • Failure to respond to initial antibiotic therapy
  • 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 symptoms are critical to recognize, as necrotizing fasciitis is a life-threatening infection that requires immediate medical attention. The infection is caused by various bacteria, most commonly Group A Streptococcus, that release toxins destroying tissue. Prompt recognition of these symptoms is essential for survival, as surgical debridement and appropriate antibiotics are necessary to treat the infection 1. It is also important to note that 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. The diagnosis of necrotizing fasciitis is often confirmed by the appearance of the subcutaneous tissues or fascial planes at operation, which are swollen and dull gray in appearance with stringy areas of necrosis. Anyone experiencing severe pain with seemingly minor skin changes, especially if accompanied by fever and rapid worsening, should seek emergency care immediately 1.

From the Research

Symptoms of Necrotizing Fasciitis

The symptoms of necrotizing fasciitis include:

  • Local pain and tenderness, which was the most common symptom reported by 90.3% of patients in a study 2
  • Septic shock, which occurred in 12.9% of patients and strongly correlated with mortality 2
  • Other symptoms may include:
    • Redness and swelling of the affected area
    • Warmth or tenderness to the touch
    • Blistering or peeling of the skin
    • Fever and chills
    • General feeling of illness or malaise

Affected Areas

Necrotizing fasciitis can affect various parts of the body, including:

  • Perineum (46.8% of cases) 2
  • Lower limbs (35.5% of cases) 2
  • Upper limbs and axillary region (8.1% of cases) 2
  • Abdominal wall

Coexisting Conditions

Certain coexisting conditions may increase the risk of developing necrotizing fasciitis, including:

  • Diabetes mellitus (40.3% of patients) 2
  • Hypertension (25.8% of patients) 2
  • Obesity (17.7% of patients) 2

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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