What is the treatment for impetigo?

Treatment of Impetigo

Topical mupirocin is the first-line treatment for localized impetigo, while oral antibiotics are recommended for extensive disease or when topical therapy is impractical. 1, 2

Diagnosis and Clinical Presentation

• Impetigo is a highly contagious, superficial bacterial skin infection most commonly affecting children 2-5 years of age 3
• Two principal types exist: nonbullous impetigo (70% of cases) and bullous impetigo (30% of cases) 3
• Nonbullous impetigo presents with honey-colored crusts on face and extremities, caused by Staphylococcus aureus or Streptococcus pyogenes 3
• Bullous impetigo presents with flaccid bullae, exclusively caused by S. aureus 3
• Lesions typically occur on exposed areas of the body, particularly face and extremities 4

Treatment Algorithm

First-Line Treatment: Topical Antibiotics

• Mupirocin 2% ointment applied three times daily for 5-7 days is the preferred topical treatment 1, 2
• Clinical efficacy rates for mupirocin are 71-93%, significantly higher than placebo (35%) 2
• Mupirocin is effective against both S. aureus and S. pyogenes, the primary causative organisms 2
• Topical therapy is preferred for limited disease due to fewer systemic side effects 5
• Retapamulin is an alternative topical agent when available 5

Second-Line Treatment: Oral Antibiotics

Oral antibiotics should be used when:

• Impetigo is extensive or involves multiple sites 1
• Topical therapy is impractical 5
• No response to topical therapy after 3-5 days 1
• Systemic symptoms are present 1

For presumed methicillin-susceptible S. aureus (MSSA):

• Dicloxacillin: 250 mg four times daily for adults 1, 5
• Cephalexin: 250-500 mg four times daily for adults 1, 5
• Amoxicillin-clavulanate: 875/125 mg twice daily for adults 5

For suspected or confirmed MRSA:

• Clindamycin: 300-450 mg three times daily for adults 1, 5
• Trimethoprim-sulfamethoxazole: 1-2 double-strength tablets twice daily for adults 1, 5
• Doxycycline: 100 mg twice daily (not for children under 8 years) 5

Important Clinical Considerations

• Penicillin alone is not effective for impetigo as it lacks adequate coverage against S. aureus 1, 5
• Duration of therapy: 5-7 days for topical treatment and 5-10 days for oral antibiotics 1
• Obtain cultures from lesions if there is treatment failure, MRSA is suspected, or in cases of recurrent infections 1
• Mupirocin has shown equal or superior efficacy to oral erythromycin in clinical trials 2, 6
• Increasing prevalence of antibiotic-resistant bacteria should be considered when selecting empiric therapy 3
• Keep lesions covered with clean, dry bandages and maintain good personal hygiene to prevent spread 1

Special Populations

• For pregnant patients, cephalexin is generally considered safe 1, 5
• Avoid tetracyclines (doxycycline, minocycline) in children under 8 years and pregnant women 1, 5
• For pediatric patients, dosing should be adjusted appropriately:
  • Dicloxacillin: 12 mg/kg/day in 4 divided doses 5
  • Cephalexin: 25 mg/kg/day in 4 divided doses 5
  • Clindamycin: 10-20 mg/kg/day in 3 divided doses 5

Monitoring and Follow-up

• Clinical improvement should be seen within 3-5 days of starting treatment 7
• Re-evaluate if no improvement after 48-72 hours of therapy 5
• Most cases resolve within 2-3 weeks without scarring 3
• Consider alternative diagnosis if presentation is atypical or not responding to appropriate therapy 5