What is the recommended treatment for impetigo?

Treatment of Impetigo

For limited impetigo, topical mupirocin is the first-line treatment, while extensive disease, treatment failure after 3-5 days, or systemic symptoms require oral antibiotics targeting both S. aureus and S. pyogenes. 1, 2

Initial Treatment Selection

Topical Therapy (First-Line for Limited Disease)

• Mupirocin 2% ointment applied three times daily is the most effective topical agent for impetigo caused by S. aureus and S. pyogenes 1, 3
• Retapamulin is an FDA-approved alternative for patients ≥9 months old, effective against methicillin-susceptible S. aureus and S. pyogenes 4
• Bacitracin and neomycin are considerably less effective and should not be used 1
• Clinical improvement should be evident within 3-5 days; if not, switch to oral antibiotics 2, 5

Important caveat: Mupirocin resistance has been increasingly documented, particularly in areas with high MRSA prevalence 6. If topical therapy fails, do not simply switch to another topical agent—move to oral antibiotics 2.

Oral Antibiotic Therapy (For Extensive Disease)

Indications for oral antibiotics include: 2

• Numerous lesions
• Lesions on face, eyelid, or mouth
• Failure to respond to topical therapy after 3-5 days
• Need to limit spread to others
• Systemic symptoms present

For Presumed Methicillin-Susceptible S. aureus (MSSA):

• Dicloxacillin 250 mg four times daily (adults) or 12 mg/kg/day in 4 divided doses (children) 2, 6
• Cephalexin 250-500 mg four times daily (adults) or 25 mg/kg/day in 4 divided doses (children) 2, 6
• Amoxicillin-clavulanate 875/125 mg twice daily (adults) or 25 mg/kg/day in 2 divided doses (children) 6

For Suspected or Confirmed MRSA:

• Clindamycin 300-450 mg three times daily (adults) or 10-20 mg/kg/day in 3 divided doses (children) 2, 6
• Trimethoprim-sulfamethoxazole 1-2 double-strength tablets twice daily (adults) or 8-12 mg/kg/day in 2 divided doses (children) 2, 6
• Doxycycline 100 mg twice daily (adults only; avoid in children <8 years) 6

Critical pitfall: Penicillin alone is NOT effective for impetigo because it lacks adequate coverage against S. aureus 2, 6. This is a common prescribing error that leads to treatment failure.

Treatment Duration

• Topical antibiotics: 5-7 days 2
• Oral antibiotics: 5-10 days 2, 6

Special Populations

Pregnant Patients

• Cephalexin is considered safe and is the preferred oral option 2, 6
• Avoid tetracyclines (doxycycline) 6

Children Under 8 Years

• Avoid all tetracyclines including doxycycline 2, 6
• Cephalexin, dicloxacillin, or clindamycin are safe alternatives 2

Penicillin-Allergic Patients

• Clindamycin is the preferred alternative 1
• Macrolides (erythromycin) have increasing resistance rates and should be used with caution 6

When to Obtain Cultures

Obtain cultures from lesions if: 2, 6

• Treatment failure occurs
• MRSA is suspected or confirmed
• Recurrent infections develop
• Atypical clinical presentation

Infection Control Measures

• Keep lesions covered with clean, dry bandages 2
• Maintain good personal hygiene with regular handwashing 2
• Avoid sharing personal items that contact the skin 2
• For recurrent impetigo, consider decolonization strategies for S. aureus carriers 6

Treatment Failure Algorithm

If no improvement after 48-72 hours of appropriate therapy: 6

1. Reassess diagnosis and rule out deeper infection or alternative diagnosis
2. Obtain cultures to identify pathogen and resistance patterns
3. Consider MRSA and switch to clindamycin or TMP-SMX
4. For severe cases or treatment failure with oral antibiotics, consider hospitalization with IV vancomycin 6

Common pitfall: Do not use topical disinfectants as primary therapy—they are inferior to antibiotics and should not be used 7.