What antibiotics are recommended for treating cellulitis?

Antibiotic Treatment for Cellulitis

For uncomplicated cellulitis, clindamycin 300-450 mg orally three times daily for 5-7 days is recommended as first-line therapy, with treatment extension until 2-3 days after clinical resolution if inadequate improvement occurs. 1

First-Line Treatment Options for Cellulitis

Outpatient Management (Mild to Moderate Cellulitis)

• Clindamycin: 300-450 mg orally three times daily for 5-7 days 1
• Alternative options:
  • Doxycycline: 100 mg orally twice daily (not for children <8 years) 1
  • Minocycline: 200 mg loading dose, then 100 mg orally twice daily 1
  • Levofloxacin: 500 mg orally daily (effective for uncomplicated cellulitis in a 5-day course) 2, 3

Inpatient Management (Severe Cellulitis)

• IV Clindamycin: 600-900 mg every 6-8 hours 1
• IV Vancomycin: 15-20 mg/kg/dose every 8-12 hours (particularly for MRSA coverage) 1
• Alternative IV options:
  • Linezolid: 600 mg twice daily 1
  • Daptomycin: 4 mg/kg/day 1
  • Telavancin: 10 mg/kg/day 1

Treatment Considerations

Duration of Therapy

• A 5-7 day course is typically sufficient for uncomplicated cellulitis 1
• Evidence shows that 5 days of therapy is as effective as 10 days for uncomplicated cases 3, 4
• Extend therapy until 2-3 days after clinical resolution if inadequate improvement occurs 1

MRSA Coverage

• Consider MRSA coverage (clindamycin, doxycycline, or linezolid) in areas with high MRSA prevalence or if risk factors are present 1
• However, adding trimethoprim-sulfamethoxazole (for MRSA coverage) to cephalexin did not improve outcomes in non-purulent cellulitis 5

Special Populations

• Children: Clindamycin 30-40 mg/kg/day divided in 3 doses 1
• Penicillin-allergic patients: Clindamycin is a useful alternative 1
• Avoid tetracyclines in children under 8 years of age 1

Indications for Inpatient Treatment

Consider inpatient management for patients with:

• Systemic toxicity
• Rapidly progressive infection
• Extensive disease
• Significant comorbidities
• Immunosuppression
• Extremes of age
• Lack of response to oral antibiotics 1

Prevention and Management of Complications

• Elevate the affected area to reduce edema 1
• Address underlying conditions (edema, obesity, eczema, venous insufficiency) to prevent recurrence 1
• For recurrent cellulitis (3-4 episodes per year), prophylactic antibiotics may be considered 1
• Maintain good personal hygiene and keep draining wounds covered 1
• Monitor for signs of orbital involvement if cellulitis is near the eye (proptosis, pain with eye movements, vision changes) 1
• For abscesses with significant cellulitis, both incision and drainage plus antibiotic therapy are recommended 1

Common Pitfalls

• Failure to recognize and treat anaphylaxis promptly can be life-threatening 1
• Clindamycin carries a higher risk of C. difficile-associated disease compared to other oral agents 1
• Extended antibiotic courses (>7 days) have not demonstrated superior outcomes for uncomplicated cases and increase risk of adverse effects and antimicrobial resistance 1
• Obtain appropriate culture and susceptibility tests before treatment when possible, especially in severe cases 2

The evidence strongly supports a 5-7 day course of antibiotics for uncomplicated cellulitis, with clindamycin being a first-line agent recommended by the Infectious Diseases Society of America. For more severe cases requiring hospitalization, intravenous therapy with agents like vancomycin may be necessary, particularly when MRSA coverage is needed.