Necrotising fasciitis

Overview 
Theory 
Diagnosis 
Management 
Follow up 
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Key diagnostic factors

common

presence of risk factors

Key risk factors include immunosuppression due to chronic illness (e.g., diabetes mellitus, alcohol dependence); cutaneous trauma, surgery, or ulcerative conditions; varicella zoster infections; intravenous drug use; and hospitalisation.[1][2][16][24][30][43]

Necrotising fasciitis in the context of recent abdominal surgery or in the groin is most likely to be polymicrobial.

anaesthesia or severe pain over site of infection

Anaesthesia or severe pain over the site of infection indicates necrotising fasciitis.[1][2][16][53] The pain experienced with necrotising fasciitis may be disproportionate to the visible skin changes.

fever

Systemic symptom of infection, though present in only 40% of patients with necrotising fasciitis.[1][2][4][16][35]

palpitations, tachycardia, tachypnoea, hypotension, and lightheadedness

Systemic symptoms/signs of infection.[1][2][4][16][35]

nausea and vomiting

Systemic symptoms of infection.[1][35]

uncommon

delirium

Systemic symptom of infection.[1][2]

crepitus

Examination of the skin overlying the area of infection may reveal crepitus.[4][16]

vesicles or bullae

Examination of the skin overlying the area of infection may reveal vesicles or bullae.[4][16] It should be noted that patients with necrotising fasciitis can present with normal overlying skin and that skin changes overlying group A streptococcal necrotising fasciitis are a late sign.[16] Subtle skin changes such as leakage of fluid and oedema precede the overt skin changes of blistering and redness.

grey discoloration of skin

Examination of the skin overlying the area of infection may reveal greyish discoloration. It should be noted that patients with necrotising fasciitis can present with normal overlying skin and that skin changes overlying group A streptococcal necrotising fasciitis are a late sign.

oedema or induration

Examination of the skin overlying the area of infection may reveal oedema.[4] Induration may be noted beyond the area of cellulitis. It should be noted that patients with necrotising fasciitis can present with normal overlying skin and that skin changes overlying group A streptococcal necrotising fasciitis are a late sign. Subtle skin changes such as leakage of fluid and oedema precede the overt skin changes of blistering and redness.

[Figure caption and citation for the preceding image starts]: Split thickness skin grafting after surgical debridementFrom: Hasham S, Matteucci P, Stanley PRW, et al. Necrotising fasciitis. BMJ. 2005 Apr 9;330(7495):830-3 [Citation ends].[Figure caption and citation for the preceding image starts]: Necrotising fasciitis on the right abdomen of a 2-year old girl following varicella infectionFrom: de Benedictis FM, Osimani P. Necrotising fasciitis complicating varicella. BMJ Case Rep. 2009;2009:bcr2008141994 [Citation ends].

location of lesion

About half of cases occur in the extremities, with the remainder affecting the perineum, trunk, or head and neck.[1][2][16][19][20] The most common site of group A streptococcal necrotising fasciitis is the thigh. Necrotising fasciitis of a limb, especially the arm, is more likely to be due to group A streptococcus than a polymicrobial infection. Some cases of necrotising fasciitis may have associated myositis due to contiguous spread. This is more common in group A streptococcal than polymicrobial infections.

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