Necrotizing fasciitis

Necrotizing fasciitis, also known as flesh-eating disease, is an uncommon non-malignant skin disease with a high mortality.

Necrotizing fasciitis
Diagnosis in short
Necrotizing fasciitis. H&E stain.
LM	necrotic fascia - amorphous grey or pink material and neutrophils
LM DDx	vasculitis
Gross	sloughing, bulae, erythema
Site	skin / subcutaneous tissue
Clinical history	+/-trauma
Signs	subcutaneous emphysema, edema, skin sloughing, bulae, erythema, signs of sepsis
Symptoms	pain
Prevalence	uncommon
Prognosis	poor
Clin. DDx	cellulitis, abscess
Treatment	surgical debridement, antibiotics

It should not to be confused with nodular fasciitis.

In the perineum/genital region it is known as Fournier gangrene.

General

Clinical:

• Pain - classically out-of-keep with appearance.
• Features of sepsis - late.
• Often nonspecific.

Clinical DDx:

• Abscess.
• Cellulitis.

Epidemiology:

• Classically associated with Group A streptococcus.
• High mortality.
• Usually adults, sometimes children.

Treatment:

• Operative debridement - emergency.
• Broad spectrum antibiotics.

Note:

• May be diagnosed at frozen section.

Gross

Features:

• Subcutaneous emphysema.
• Edema.
• Erythema.
• Bulae.
• Skin sloughing.

Image

• 

  Necrotizing fasciitis. (WC)

Microscopic

Features:

• Necrosis of fascia - key feature.
  • PMNs and necrotic debris (amorphous grey or pink material).
• +/-Vascular thrombosis.

Note:

• Fat lobules between septae may be normal.

DDx:

• Cellulitis.
• Vasculitis.
• Erythema nodosum.^{[citation needed]}

Images

• 

  Necrotizing fasciitis - intermed. mag. (WC)

• 

  Necrotizing fasciitis - high mag. (WC)

Sign out

Perianal Skin and Subcutaneous Tissue, Excision:
- Consistent with clinical impression of necrotizing fasciitis.

Alternate

Submitted as "Tissue from Left Elbow", Excision:
     - Skin and subcutaneous tissue with marked inflammation (see microscopic), 
       consistent with clinical impression of necrotizing fasciitis. 

Comment:
The positive tissue cultures are noted.

Micro

Necrotic fascial tissue with inflamed adipose tissue and micro-abscess formation at dermis/subcutis interface. The overlying skin is moderately inflamed and edematous appearing.

See also

• Non-malignant skin disease.