Cellulitis Organism-Specific Therapy

Organism-specific therapeutic regimens for cellulitis are provided below, including those for group A beta-hemolytic streptococci (GABHS) ^[1] and community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). ^{[2, 3, 4, 5, 6, 7]}

The Infectious Diseases Society of America (IDSA) published 2014 guidelines for the treatment of cellulitis (see Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America). ^[8]

GABHS

Outpatient treatment recommendations:

• Dicloxacillin 500 mg PO q6h for 10-14 days or
• Cephalexin 500 mg PO q6h for 10-14 days or
• Clindamycin 300-600 mg PO q8h for 10-14 days or
• Amoxicillin-clavulanate 875 mg/125 mg PO BID for 10-14d

Inpatient treatment recommendations:

• Nafcillin 2 g IV q4h for 1-3 days or
• Clindamycin 600-900 mg IV q8h

CA-MRSA

Outpatient treatment recommendations:

• No single agent demonstrates superiority; use sensitivities to guide therapy if available
• Doxycycline 100 mg PO BID for 10-14 days (not for use in pregnant women or in children) or
• Trimethoprim-sulfamethoxazole (160 mg/800 mg) DS 2 tablets PO BID for 10-14 days or
• Linezolid 600 mg PO BID for 10-14 days or
• Clindamycin 300-600mg PO q 8hrs for 10-14 days
• Some CA-MRSA strains have inducible resistance to clindamycin, and this may result in treatment failure; a D-test can be performed by microbiology to look for this

Inpatient treatment recommendations:

• Vancomycin 15 mg/kg IV q12h for 1-3 days; draw level 0.5 hours before 5th dose if checking levels or
• Daptomycin (creatinine clearance [CrCl] > 30 mL/min): 4 mg/kg IV q24h infused over 30 minutes or
• Tigecycline 100 mg IV as a single dose; then 50 mg IV q12h

Treatment Updates

In June 2017, the FDA approved delafloxacin (Baxdela) for the treatment of acute bacterial skin and skin structure infections (ABSSSI). Delafloxacin exhibits activity against both gram-positive and gram-negative pathogens, including MRSA, and is available in both intravenous (IV) and oral formulations. ^[9]  This agent should be avoided in individuals younger than 18 years.

Recommended dose:

• 300 mg IV q12hr for 5-14 days or
• 300 mg IV q12hr, then switch to a 450-mg tablet PO q12hr for 5-14 days or
• 450 mg PO q12hr for 5-14 days

Adjunctive therapy

Elevation of the affected extremity may speed resolution.

Consider surgical consultation in the following cases:

• Urgent consultation with a surgeon should be sought in the setting of crepitus, circumferential cellulitis, necrotic-appearing skin, rapidly evolving cellulitis, pain disproportional to physical examination findings, severe pain on passive movement, or other findings that raise clinical concern for necrotizing fasciitis

• Serious concern for necrotizing fasciitis or the presence of necrotic skin should prompt examination of the fascial planes by direct observation; this can be performed at the bedside by an experienced surgeon in most cases

• Circumferential cellulitis may result in compartment syndrome, and surgical decompression may be necessary; measurement of compartment pressures may be helpful in diagnosis

• Cellulitis associated with an abscess requires surgical drainage of the source of infection for adequate treatment