Continuing medical education
Lower limb cellulitis and its mimics: Part I. Lower limb cellulitis

https://doi.org/10.1016/j.jaad.2012.03.024Get rights and content

An aging population and obesity have both contributed to a rising incidence of lower limb cellulitis; the most important predisposing factors include older age, obesity, venous insufficiency, saphenous venectomy, and edema. Streptococci are the most commonly implicated pathogen, and often reside in the interdigital toes spaces. Any disruption of the skin surface can allow the organism to invade. Effective management requires an appropriate antibiotic and attention to the predisposing factors. This article summarizes the epidemiology and treatment of this common infection.

Section snippets

Definitions

Key points

  1. Clinicians should use the term “cellulitis” for superficial spreading skin infections without an underlying collection of pus

  2. The term “erysipelas” has been used in 3 different ways

Cellulitis is a superficial, diffuse, spreading infection of the skin. In the most clinically useful nomenclature, the term “cellulitis” does not refer to cutaneous inflammation associated with collections of pus, such as septic bursitis, furuncles, or cutaneous abscesses. In those situations, when redness, heat,

Predisposing factors

Key points

  1. Lower limb cellulitis occurs with about equal frequency in men and women and is more common with advancing age

  2. One attack of lower limb cellulitis predisposes to future episodes, with an annual recurrence rate of about 8% to 20%

Whether it is called erysipelas or cellulitis, this infection involves the lower extremities in about 70% to 80% of cases, as reported in large series, mostly of hospitalized patients.1, 2, 3, 4, 5, 6, 7 Its overall frequency is approximately 199 per 100,000 person-years,

Pathogenesis and pathology

Key points

  1. The organisms causing lower limb cellulitis typically enter the skin through defects in the cutaneous surface, particularly in the presence of edema, venous insufficiency, obesity, trauma, ulceration, or dermatologic disorders

  2. The reservoir for these infecting organisms is often the interdigital toe spaces, especially when maceration, scaling, and fissuring are present

Except for rarely being caused by bacteremia from another site of infection, cellulitis occurs from microbes entering the skin

Clinical features

Key points

  1. Although fever and systemic symptoms may be prominent in many patients, about 30% to 80% of patients with lower limb cellulitis are afebrile

  2. The major dermatologic features of cellulitis are redness, edema, pain, and warmth in the affected skin, often accompanied by cutaneous hemorrhage

The systemic features of infection can be prominent in patients with cellulitis and occasionally precede any signs of cutaneous inflammation by many hours.1 The mechanism is uncertain but may represent a vigorous

Diagnosis

Key points

  1. The white blood cell count, erythrocyte sedimentation rate, and C-reactive protein levels are commonly elevated, but normal values of these tests do not exclude the diagnosis of cellulitis

  2. Evidence from cultures, aspirates, biopsy specimens, and serologic studies implicate streptococci of various groups in about 75% to 90% of cases; Staphylococcus aureus (almost always methicillin-susceptible) is evident in 10% of cases

The white blood cell count is elevated in about 35% to 50% of patients,1, 7,

Treatment

Key points

  1. Most patients do not require hospitalization, and a 5-day regimen of oral antimicrobials effective against streptococci and methicillin-susceptible Staphylococcus aureus, such as dicloxacillin or cephalexin, should usually suffice

  2. A brief course of oral corticosteroids significantly shortens the duration of illness and may reduce the frequency of subsequent episodes

As indicated above, most patients respond well to penicillin, and oral therapy is equivalent to parenteral administration in

Unusual causes of lower limb cellulitis

Key point

  1. Clinicians should suspect unusual organisms as the causes of cellulitis in immunocompromised hosts and in patients with chronic liver disease, animal bites, immersion in salt or fresh water, and penetrating trauma

Conclusion

Cellulitis of the lower limbs is a superficial spreading infection primarily caused by streptococci of various groups, less commonly by S aureus, and occasionally by other microbes. Infection with MRSA is rare. Treatment of cases of typical lower limb cellulitis includes antibiotics active against streptococci and S aureus, leg elevation, and systemic corticosteroids. Clinicians should treat any underlying or predisposing dermatologic conditions, such as venous eczema, and especially

References (111)

  • J.M. Fernández et al.

    Bacteremic cellulitis caused by non-01, non-0139 Vibrio cholerae: report of a case in a patient with hemochromatosis

    Diag Microbiol Infect Dis

    (2000)
  • Y. Horowitz et al.

    Gram-negative cellulitis complicating cirrhosis

    Mayo Clin Proc

    (2004)
  • M.A. Bogaert et al.

    Serratia cellulitis and secondary infection of leg ulcers by Serratia

    J Am Acad Dermatol

    (1991)
  • C.L. Cooper et al.

    Bullous cellulitis caused by Serratia marcescens

    Int J Infect Dis

    (1998)
  • B. Eriksson et al.

    Erysipelas: clinical and bacteriologic spectrum and serological aspects

    Clin Infect Dis

    (1996)
  • A. Jeng et al.

    The role of β-hemolytic streptococci in causing diffuse, nonculturable cellulitis: a prospective investigation

    Medicine (Baltimore)

    (2010)
  • C. Jorup-Rönström

    Epidemiological, bacteriological and complicating features of erysipelas

    Scand J Infect Dis

    (1986)
  • P.-I. Bergkvist et al.

    Antibiotic and prednisolone therapy of erysipelas: a randomized, double blind, placebo-controlled study

    Scand J Infect Dis

    (1997)
  • P. Corwin et al.

    Randomised controlled trial of intravenous antibiotic treatment for cellulitis at home compared with hospital

    BMJ

    (2005)
  • J. Carratalà et al.

    Factors associated with complications and mortality in adult patients hospitalized for infectious cellulitis

    Eur J Microbiol Infect Dis

    (2003)
  • S. Björnsdóttir et al.

    Risk factors for acute cellulitis of the lower limb: a prospective case-control study

    Clin Infect Dis

    (2005)
  • A. Dupuy et al.

    Risk factors for erysipelas of the leg (cellulitis): case control study

    BMJ

    (1999)
  • J.C. Roujeau et al.

    Chronic dermatomycoses of the foot as risk factors for acute bacterial cellulitis of the leg: a case-control study

    Dermatology

    (2004)
  • M. Mokni et al.

    Risk factors for erysipelas of the leg in Tunisia: a multicenter case-control study

    Dermatology

    (2006)
  • M. Dan et al.

    Incidence of erysipelas following venectomy for coronary artery bypass surgery

    Infection

    (1987)
  • M. Karakaş et al.

    Manifestations of cellulitis after saphenous venectomy for coronary artery bypass surgery

    J Eur Acad Dermatol Venereol

    (2002)
  • L.M. Baddour et al.

    Recurrent cellulitis after coronary artery bypass surgery. Association with superficial fungal infection in saphenous venectomy limbs

    JAMA

    (1984)
  • J. Greenberg et al.

    Vein-donor-leg cellulitis after coronary artery bypass surgery

    Ann Intern Med

    (1982)
  • P.I. Bergkvist et al.

    Relapse of erysipelas following treatment with prednisolone or placebo in addition to antibiotics: a 1-year follow-up

    Scand J Infect Dis

    (1998)
  • C. Jorup-Rönström et al.

    Recurrent erysipelas: predisposing factors and costs of prophylaxis

    Infection

    (1987)
  • D.R. McNamara et al.

    A predictive model of recurrent lower extremity cellulitis in a population-based cohort

    Arch Intern Med

    (2007)
  • N.H. Cox

    Oedema as a risk factor for multiple episodes of cellulitis/erysipelas of the lower leg: a series with community follow-up

    Br J Dermatol

    (2006)
  • F. Pavlostsky et al.

    Recurrent erysipelas: risk factors

    J Dtsch Dermatol Ges

    (2004)
  • S. Leclerc et al.

    Recurrent erysipelas: 47 cases

    Dermatology

    (2007)
  • R.J. Damstra et al.

    Erysipelas as a sign of subclinical primary lymphoedema: a prospective quantitative scintigraphic study of 40 patients with unilateral erysipelas of the leg

    Br J Dermatol

    (2008)
  • J.K. Soo et al.

    Lymphatic abnormalities demonstrated by lymphoscintigraphy after lower limb cellulitis

    Br J Dermatol

    (2008)
  • T. Duvanel et al.

    Quantitative cultures of biopsy specimens from cutaneous cellulitis

    Arch Intern Med

    (1989)
  • J.M.P. De Godoy et al.

    Lymphoscintigraphic evaluation in patients after erysipelas

    Lymphology

    (2000)
  • J.D. Semel et al.

    Association of athlete’s foot with cellulitis of the lower extremities: diagnostic value of bacterial cultures of ipsilateral interdigital space samples

    Clin Infect Dis

    (1996)
  • B.K.G. Eriksson

    Anal colonization of group G beta-hemolytic streptococci in relapsing erysipelas of the lower extremity

    Clin Infect Dis

    (1999)
  • J. Dankert et al.

    Recurrent acute leg cellulitis after hysterectomy with pelvic lymphadenectomy

    Br J Obstet Gynaecol

    (1987)
  • R.T. Ellison et al.

    Recurrent postcoital lower-extremity streptococcal erythroderma in women. Streptococcal-sex syndrome

    JAMA

    (1987)
  • A.N. Binnick et al.

    Recurrent erysipelas caused by group B streptococcus organisms

    Arch Dermatol

    (1980)
  • T. Siljander et al.

    Acute bacterial, nonnecrotizing cellulitis in Finland: microbiological findings

    Clin Infect Dis

    (2008)
  • C. Chartrier et al.

    Erysipelas

    Int J Dermatol

    (1990)
  • E.W. Hook et al.

    Microbiologic evaluation of cutaneous cellulitis in adults

    Arch Intern Med

    (1986)
  • D.M. Musher et al.

    Treatment of cellulitis with ceforanide

    Antimicrob Agents Chemother

    (1980)
  • P. Bernard et al.

    Streptococcal cause of erysipelas and cellulitis in adults. A microbiologic study using a direct immunofluorescence technique

    Arch Dermatol

    (1989)
  • C. Liu et al.

    Clinical practice guidelines by the Infectious Diseases Society of America for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children

    Clin Infect Dis

    (2011)
  • Cited by (76)

    • Distinguishing Cellulitis from Its Noninfectious Mimics: Approach to the Red Leg

      2021, Infectious Disease Clinics of North America
      Citation Excerpt :

      About 30% to 80% of patients with lower-limb cellulitis are afebrile.6 Leukocytosis and elevated inflammatory markers (eg, erythrocyte sedimentation rate [ESR], C-reactive protein [CRP]) may suggest a diagnosis of cellulitis, although they are also not reliable diagnostic criteria, as they occur in only 35% to 50% and 60% to 95% of patients, respectively; therefore, their absence is less helpful in ruling out cellulitis.6 Clinical decision-making tools to improve the diagnosis of cellulitis are being developed based on small preliminary studies, including the ALT-70 and NEW HAvUN scores.

    • Most prevalent infectious skin disease

      2020, FMC Formacion Medica Continuada en Atencion Primaria
    View all citing articles on Scopus

    Funding sources: None.

    View full text