Treatment of Staphylococcal Skin Infections
First-Line Treatment
For methicillin-susceptible Staphylococcus aureus (MSSA) skin infections, dicloxacillin or cephalexin for 7 days is the recommended first-line oral therapy, while incision and drainage is the primary treatment for any purulent collection. 1
Procedural Management
- Incision and drainage is the cornerstone of treatment for all abscesses, furuncles, and carbuncles and may be adequate as monotherapy for simple, localized abscesses without systemic signs. 1, 2, 3
- Culture the purulent drainage before initiating antibiotics to confirm the pathogen and guide therapy. 2, 3
Oral Antibiotic Options for MSSA
- Dicloxacillin or cephalexin are the preferred first-line agents because most community-acquired S. aureus isolates from impetigo and ecthyma are methicillin-susceptible. 1
- Cephalexin can be dosed twice daily (enhancing compliance) and achieves cure rates of 90% or higher for staphylococcal skin infections. 4, 5
- Treatment duration should be 7 days for uncomplicated infections. 1
When to Add Antibiotics to Incision and Drainage
Antibiotics are indicated when the abscess is associated with: 1, 3
- Severe or extensive disease involving multiple sites
- Rapid progression with associated cellulitis
- Systemic signs (fever >38°C, tachycardia, tachypnea, abnormal WBC)
- Comorbidities or immunosuppression
- Extremes of age
- Difficult-to-drain locations (face, hand, genitalia)
- Lack of response to drainage alone
Second-Line Treatment (MRSA Coverage)
When MRSA is suspected or confirmed, oral options include trimethoprim-sulfamethoxazole (TMP-SMX), doxycycline, or clindamycin for 5-10 days. 1
Oral Antibiotic Selection for MRSA
Clindamycin 300-450 mg three times daily is preferred when coverage for both MRSA and β-hemolytic streptococci is needed, though cross-resistance can occur in erythromycin-resistant strains. 1, 2, 3
TMP-SMX 1-2 double-strength tablets twice daily is highly effective against MRSA but does not adequately cover β-hemolytic streptococci, so consider adding a β-lactam (such as amoxicillin) if streptococcal coverage is needed. 1, 2, 3
Doxycycline 100 mg twice daily or minocycline 200 mg loading dose then 100 mg twice daily are effective alternatives but are contraindicated in children under 8 years of age and pregnant women in the third trimester. 1, 2, 3
Important Caveats
- Local resistance patterns should guide selection—if clindamycin resistance exceeds 10%, choose an alternative agent. 1
- For purulent cellulitis (cellulitis with purulent drainage but no drainable abscess), empirical MRSA coverage is recommended. 1
- For nonpurulent cellulitis, empirical therapy should target β-hemolytic streptococci first; add MRSA coverage only if the patient fails to respond to β-lactam therapy. 1
Third-Line Treatment (Severe/Hospitalized Cases)
For hospitalized patients with complicated skin infections or systemic toxicity, intravenous vancomycin 15-20 mg/kg every 8-12 hours is the first-line parenteral option. 1, 2
Intravenous Antibiotic Options
- Vancomycin remains the mainstay for serious MRSA infections requiring hospitalization. 1, 2, 6
- Linezolid 600 mg IV/PO twice daily is an alternative with excellent MRSA efficacy and no cross-resistance with other classes, though it is more expensive. 1, 2, 3
- Daptomycin 4 mg/kg IV once daily is effective for complicated skin infections. 1, 2
- Telavancin 10 mg/kg IV once daily is another option for hospitalized patients. 1
- Ceftriaxone once daily offers an advantage for moderate-to-severe MSSA infections requiring IV therapy, as it may allow outpatient parenteral treatment. 7
Treatment Duration for Complicated Infections
- Treat for 7-14 days depending on clinical response and severity. 1, 2, 3
- Reassess within 48-72 hours to ensure adequate response. 2
Pediatric Considerations
- Mupirocin 2% topical ointment is appropriate for minor infections like impetigo in children. 1, 3
- Clindamycin 10-13 mg/kg/dose every 6-8 hours (up to 40 mg/kg/day) is the preferred oral option for children with MRSA infections if local resistance is low. 1, 2, 3
- TMP-SMX 4-6 mg/kg/dose (trimethoprim component) every 12 hours is an alternative for pediatric MRSA infections. 2
- Tetracyclines must be avoided in children under 8 years of age due to risk of tooth discoloration and bone growth effects. 1, 2, 3
- For hospitalized children with complicated infections, vancomycin is recommended, with linezolid as an alternative. 1
Common Pitfalls to Avoid
- Do not use rifampin as monotherapy or adjunctive therapy for skin and soft tissue infections—resistance develops rapidly. 1, 3, 6
- Do not rely on vancomycin for outpatient oral therapy—it is not absorbed orally and requires IV administration. 3
- Do not assume all cellulitis requires MRSA coverage—nonpurulent cellulitis is typically streptococcal and should be treated with a β-lactam first. 1
- Do not prescribe antibiotics for simple abscesses that can be adequately drained—incision and drainage alone may suffice. 1, 2, 3