History and exam

Key diagnostic factors

common

history of traumatic or nontraumatic cutaneous lesion

Cutaneous injury, surgery, trauma, intravenous drug use, or chronic or acute skin conditions (e.g., eczema, psoriasis, cutaneous ulcers, and burns) may serve as a cutaneous portal of entry for infective organisms.​​​[1]​​​[5][16]​​[29]

anesthesia or severe pain over site of cellulitis

Anesthesia or severe pain over the site of cellulitis indicates necrotizing fasciitis.​[1][5][16]​​​​[43]​​ The pain experienced with necrotizing fasciitis may be disproportionate to the visible skin changes.

fever

Systemic symptom of infection, though present in only 40% of patients with necrotizing fasciitis.​[1][3]​​​[5]​​​​[16]

palpitations, tachycardia, tachypnea, hypotension, and lightheadedness

Systemic symptoms/signs of infection.​[1][3]​​​[5]​​​​[16]

nausea and vomiting

Systemic symptoms of infection.​[1]​​[5]​​

uncommon

delirium

Systemic symptom of infection.​[1]​​[5]​​

crepitus

Examination of the skin overlying the area of cellulitis may reveal crepitus.[3][16]​​

vesicles or bullae

Examination of the skin overlying the area of cellulitis may reveal vesicles or bullae.[3][16]​ It should be noted that patients with necrotizing fasciitis can present with normal overlying skin and that skin changes overlying group A streptococcal necrotizing fasciitis are a late sign.[16]​ Subtle skin changes such as leakage of fluid and edema precede the overt skin changes of blistering and redness.[Figure caption and citation for the preceding image starts]: Small areas of skin necrosis in a young woman with cellulitis and necrotizing fasciitis of her lower abdomen 5 days after a cesarean sectionFrom: Hasham S, Matteucci P, Stanley PRW, et al. Necrotising fasciitis. BMJ. 2005 Apr 9;330(7495):830-3 [Citation ends].com.bmj.content.model.Caption@282e577f​

gray discoloration of skin

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

edema or induration

Examination of the skin overlying the area of cellulitis may reveal edema.[5]​ Induration may be noted beyond the area of cellulitis.[5]​ It should be noted that patients with necrotizing fasciitis can present with normal overlying skin and that skin changes overlying group A streptococcal necrotizing fasciitis are a late sign. Subtle skin changes such as leakage of fluid and edema precede the overt skin changes of blistering and redness.​​[Figure caption and citation for the preceding image starts]: Small areas of skin necrosis in a young woman with cellulitis and necrotizing fasciitis of her lower abdomen 5 days after a cesarean sectionFrom: Hasham S, Matteucci P, Stanley PRW, et al. Necrotising fasciitis. BMJ. 2005 Apr 9;330(7495):830-3 [Citation ends].com.bmj.content.model.Caption@32e29371[Figure caption and citation for the preceding image starts]: Necrotizing 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].com.bmj.content.model.Caption@52289b04

location of lesion

About half of cases occur in the extremities, with the remainder concentrated in the perineum, trunk, and head and neck areas.​​[1][5][16]​​​​​​[19][20] The most common site of group A streptococcal necrotizing fasciitis is the thigh and necrotizing fasciitis of a limb, especially the arm, is more likely to be due to group A streptococcus than a polymicrobial infection. Some cases of necrotizing fasciitis may have associated myositis due to contiguous spread. This is more common in group A streptococcal than polymicrobial infections.

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

Risk factors

strong

inpatient contact with index case

Patient to patient spread of group A streptococcal infection, with median interval of 4 days to spread from index case to second case.​​​[1]​​​[29]

Varicella zoster infection

Serves as a cutaneous portal of entry for infective organisms.​​​[1]​​​[29]

cutaneous injury, surgery, trauma

Serve as a cutaneous portal of entry for infective organisms.​[1][5]​​[16]​

nontraumatic skin lesions

Chronic or acute skin conditions, for example, eczema, psoriasis, cutaneous ulcers, and burns, may serve as a cutaneous portal of entry for infective organisms.​​​[1][5]​​[16]​​​​[29]​​

intravenous drug use

Intravenous drug use provides a cutaneous portal of entry for infective organisms.[16]

weak

chronic illness

A generalized immunosuppressed state as a consequence of longstanding disease (alcoholism, diabetes mellitus, cardiac or pulmonary disease, peripheral vascular disease, renal failure) may predispose to soft-tissue infections.​​​[1][3]​​[5][16]​​​​​[29]​​

immunosuppression

Immunosuppression due to malignancy and/or chemotherapy or radiation therapy, medications (especially chronic corticosteroid use), or infection (HIV) may predispose to soft-tissue infections.[3]​ Immunosuppressed status may lead to a delay in diagnosis and surgical management leading to greater risk of death.[16][25][30]

nonsteroidal anti-inflammatory drugs (NSAIDs)

It has been postulated that use of NSAIDs may mask symptoms of necrotizing fasciitis, delaying diagnosis and that suppression of neutrophils and alterations of cytokine production caused by NSAIDs may impair response to infection and allow progression to severe disease. In an animal model of group A streptococcus soft tissue infection, ibuprofen worsened disease and increased mortality.[31][32]​ However, good evidence for the association of NSAIDs and necrotizing fasciitis in humans is not available.

Use of this content is subject to our disclaimer