What is the treatment for staphylococcal (Staph) skin infections, including impetigo and ecthyma?

Treatment for Staphylococcal Skin Infections, Impetigo, and Ecthyma

For staphylococcal skin infections, topical mupirocin 2% ointment is the first-line treatment for localized impetigo, while oral antibiotics such as dicloxacillin or cephalexin are recommended for ecthyma or extensive impetigo, with alternative agents like doxycycline, clindamycin, or sulfamethoxazole-trimethoprim when MRSA is suspected. 1, 2

Treatment Approach Based on Infection Type

Impetigo Treatment

1. Localized impetigo (first-line):

   • Topical mupirocin 2% ointment applied to affected areas twice daily for 5 days 1, 3
   • Alternative: retapamulin applied twice daily for 5 days 1, 2

2. Extensive impetigo or multiple lesions:

   • Oral antibiotics for 7 days 1:
     • Methicillin-susceptible S. aureus (MSSA): dicloxacillin or cephalexin
     • Suspected/confirmed MRSA: doxycycline, clindamycin, or sulfamethoxazole-trimethoprim (SMX-TMP)
     • Streptococci alone: oral penicillin

Ecthyma Treatment

• Always requires oral antibiotics for 7 days 1:
  • First-line: dicloxacillin or cephalexin (for MSSA)
  • For suspected/confirmed MRSA: doxycycline, clindamycin, or SMX-TMP
  • For streptococcal infection only: oral penicillin

Diagnostic Considerations

• Gram stain and culture of pus or exudates are recommended to identify causative organisms (S. aureus and/or β-hemolytic Streptococcus) 1
• Treatment can begin before culture results in typical cases 1
• If no improvement within 3-5 days, obtain bacterial culture and sensitivity testing 2

Antibiotic Dosing Guidelines

• Topical mupirocin: Apply to affected areas 2-3 times daily for 5-7 days 2, 3
• Oral antibiotics (adults): 2
  • Cephalexin: 250 mg four times daily
  • Clindamycin: 300-450 mg three times daily
  • SMX-TMP: 1-2 double-strength tablets twice daily
• Oral antibiotics (children): 2
  • Cephalexin: 25-50 mg/kg/day in 3-4 divided doses
  • Clindamycin: 10-13 mg/kg/dose every 6-8 hours

Special Considerations

MRSA Infections

• For confirmed MRSA infections, use doxycycline, clindamycin, or SMX-TMP 1, 2
• Note that SMX-TMP covers MRSA but is inadequate for streptococcal infections 4

Poststreptococcal Glomerulonephritis Prevention

• Systemic antimicrobials should be used during outbreaks of poststreptococcal glomerulonephritis to eliminate nephritogenic strains of S. pyogenes 1

Recurrent Infections

• For patients with recurrent skin infections, consider a 5-day decolonization regimen with: 2
  • Intranasal mupirocin
  • Daily chlorhexidine washes
  • Daily decontamination of personal items

Prevention Measures

• Keep draining wounds covered with clean, dry bandages 2
• Practice regular handwashing 2
• Avoid sharing personal items that contact skin 2
• Change clothing that contacts affected areas daily 2
• Clean high-touch surfaces regularly 2

Treatment Pitfalls to Avoid

• Failing to consider MRSA in recalcitrant cases 2
• Using penicillin alone for impetigo (inferior to other antibiotics) 2, 4
• Inadequate duration of therapy 2
• Relying solely on topical therapy for extensive disease 2
• Not addressing underlying conditions that predispose to recurrent infection 2

Expected Outcomes

• Resolution typically occurs within 7-10 days of starting appropriate treatment 2
• Clinical response should be evaluated within 48-72 hours of initiating therapy 2