Cellulitis Guidelines

Updated: Apr 26, 2022
  • Author: Thomas E Herchline, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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Guidelines Summary

In 2014, the Infectious Diseases Society of America (IDSA) published updated guidelines for the management of various SSTIs, with emphasis on the clinical skills needed to properly treat the likely pathogens before and after culture results are available. [4]

The guidelines include a treatment algorithm that begins by determining whether the cellulitis is nonpurulent or purulent, as follows [4] :

  • Nonpurulent cellulitis includes rapidly spreading superficial cellulitis and erysipelas; typically involves groups A, B, C, and G beta-hemolytic streptococci and, occasionally, methicillin-susceptible Staphylococcus aureus (MSSA); these infections are diagnosed clinically, and cultures are not mandatory since there is usually no reliable and easily accessible source of specimen to culture
  • Purulent cellulitis includes cutaneous abscesses, carbuncles, furuncles, and sebaceous cyst infection typically involving S aureus, both MSSA and methicillin-resistant S aureus (MRSA); culture should be performed when possible to determine the pathogen’s presence and resistance pattern

Outpatient therapy with oral antibiotics is indicated for healthy individuals who have no evidence of systemic inflammatory response syndrome (SIRS). [4]

Inpatient therapy with parenteral antibiotics is recommended in patients with associated SIRS, hemodynamic instability, and/or mental status changes. Poor compliance, failure to respond to oral antibiotics, facial involvement, and immune suppression are additional indications for inpatient parenteral therapy until the patient is stable and improving. The initial antibiotic selection should cover MRSA in patients with coexisting penetrating and/or surgical trauma, evidence of MRSA infection elsewhere, known nasal MRSA colonization, and/or intravenous drug abuse. Coverage should also take into consideration the prevalence of MRSA in the patient’s hospital and community. [4]


Nonpurulent Cellulitis

According to the IDSA treatment algorithm, any of the following oral antibiotics is indicated for mild infection [4] :

In patients with moderate infection, intravenous antibiotics options include the following [4] :

In patients with severe infection and suspected polymicrobic infection, vancomycin plus piperacillin/tazobactam is recommended. [4]


Purulent Cellulitis

According to the IDSA treatment algorithm, incision and drainage of abscess is indicated for all purulent infections and is sufficient for mild infections. For moderate infections, options for oral antibiotics include the following:

For severe infection or patients in whom incision and drainage plus oral antibiotics have failed, inpatient intravenous treatments include the following:


Staphylococcal and Streptococcal Skin and Soft Tissue Infections

Once microorganisms are identified based on cultures, treatment is tailored to the patient’s needs. The most common organisms are staphylococcal and streptococcal strains. [4]

Impetigo (Staphylococcus and Streptococcus)

IDSA treatment recommendations include any of the following oral antibiotics [4] :

  • Dicloxacillin
  • Cephalexin
  • Erythromycin (some strains of S aureus and S pyogenes are resistant)
  • Clindamycin
  • Amoxicillin-clavulanate

In patients with a limited number of lesions, retapamulin or mupirocin ointment may be applied topically.

Methicillin-susceptible S aureus (MSSA)

IDSA guidelines recommend oral dicloxacillin or IV nafcillin or oxacillin as the drugs of choice, but note that nafcillin and oxacillin are inactive against MRSA. For patients allergic to penicillin, cefazolin is indicated. [4]

Methicillin-resistant S aureus (MRSA)

IDSA recommends the following outpatient oral antibiotics [4] :

Some MRSA strains have inducible resistance, and this may result in treatment failure; a D-test can be performed by microbiology for evaluation.

Inpatient IV antibiotic treatment options include the following [4] :