What is the treatment for impetigo?

Treatment of Impetigo

The first-line treatment for impetigo is topical mupirocin 2% ointment applied three times daily for 5-7 days for limited lesions. 1

Treatment Algorithm

First-Line Treatment: Topical Antibiotics

• Mupirocin 2% ointment is FDA-approved for the topical treatment of impetigo due to Staphylococcus aureus and Streptococcus pyogenes, applied to affected areas three times daily for 5-7 days 1, 2
• Retapamulin 1% ointment (Altabax) is an effective alternative, applied twice daily for 5 days for patients aged 9 months or older 1, 3
• Topical antibiotics have been shown to have better cure rates than placebo (risk ratio 2.24) 4
• Topical therapy is preferred for limited disease due to fewer systemic side effects compared to oral antibiotics 5, 6

Second-Line Treatment: Oral Antibiotics

• Oral antibiotics are recommended in cases of:
  • Extensive disease (multiple lesions or large affected areas)
  • When topical therapy is impractical
  • Failure of topical treatment
  • Presence of systemic symptoms 1
• First-line oral options include:
  • Dicloxacillin
  • First-generation cephalosporins (e.g., cephalexin) 1
• Oral erythromycin has been shown to be slightly less effective than topical mupirocin (risk ratio 1.07) 4
• Penicillin V is inferior to erythromycin and cloxacillin and should not be used as monotherapy 5, 4

Special Considerations

Community-Acquired MRSA (CA-MRSA)

• Consider empiric therapy for CA-MRSA in the following scenarios:
  • Patients at risk for CA-MRSA infection
  • Failure to respond to first-line therapy
  • High local prevalence of CA-MRSA 1
• Treatment options for suspected CA-MRSA include:
  • Trimethoprim-sulfamethoxazole (covers MRSA but inadequate for streptococcal infections)
  • Clindamycin
  • Doxycycline 1, 5

Treatment Duration and Follow-up

• Complete the full course of prescribed antibiotics even if symptoms improve quickly 1
• Most cases resolve within 2-3 weeks without scarring 5
• Monitor for complications such as post-streptococcal glomerulonephritis, though these are rare 1, 5

Important Clinical Pearls

• Impetigo primarily affects children 2-5 years of age and is highly contagious 1, 5
• There are two principal types: nonbullous (70% of cases) and bullous (30% of cases) 5
• Diagnosis is typically made clinically based on characteristic honey-colored crusts (nonbullous) or flaccid bullae (bullous) 5, 6
• Topical disinfectants are inferior to antibiotics and should not be used 4, 6
• Growing antibiotic resistance is a concern, particularly for erythromycin and mupirocin 5, 4
• For retapamulin, a newer topical agent, no resistance has yet been reported 4

Treatment Pitfalls to Avoid

• Failing to complete the full course of antibiotics, which can lead to treatment failure or recurrence 1
• Using penicillin V as monotherapy, which has poor efficacy against S. aureus 5, 4
• Overlooking the possibility of MRSA in cases that fail to respond to initial therapy 1, 5
• Using topical disinfectants instead of antibiotics, as they have been shown to be ineffective 4, 6
• Not considering oral antibiotics for extensive disease or when topical treatment is impractical 1, 6