What do you put on impetigo?

Treatment Options for Impetigo

For impetigo, topical mupirocin ointment applied three times daily is the first-line treatment for limited lesions, while oral antibiotics like dicloxacillin or cephalexin should be used for extensive disease. 1

Understanding Impetigo

Impetigo is a highly contagious superficial bacterial skin infection that presents in two forms:

• Nonbullous impetigo (70% of cases): Characterized by honey-colored crusts on exposed areas like the face and extremities
• Bullous impetigo (30% of cases): Presents with flaccid bullae that may rupture, leaving thin crusts

The infection is typically caused by:

• Staphylococcus aureus (most common)
• Streptococcus pyogenes (Group A strep)
• Or both organisms together

Treatment Algorithm

1. For Limited Lesions (Few, Localized)

• First choice: Topical mupirocin 2% ointment applied three times daily for 5-7 days 1, 2
  • Clinical efficacy rates of 71-93% in studies 2
  • Complete pathogen eradication in 94-100% of cases 2

2. For Extensive Disease (Multiple Lesions or Widespread)

• Oral antibiotics for 7 days with one of the following: 1
  • Dicloxacillin: 250 mg four times daily (adults); 12 mg/kg/day in 4 divided doses (children) 1
  • Cephalexin: 250 mg four times daily (adults); 25 mg/kg/day in 4 divided doses (children) 1
  • Amoxicillin/clavulanate: 875/125 mg twice daily (adults); 25 mg/kg/day of amoxicillin component in 2 divided doses (children) 1

3. For Penicillin-Allergic Patients

• For mild allergy: Cephalexin (if no immediate hypersensitivity reaction) 1
• For severe allergy: 1
  • Clindamycin: 300-400 mg three times daily (adults); 10-20 mg/kg/day in 3 divided doses (children)
  • Doxycycline: 100 mg twice daily (adults, and children ≥8 years)
  • Trimethoprim-sulfamethoxazole (for suspected MRSA only)

4. For Suspected MRSA

• Clindamycin or trimethoprim-sulfamethoxazole (note: trimethoprim-sulfamethoxazole should not be used as monotherapy if streptococcal infection is suspected) 1

Important Clinical Considerations

• Duration of therapy: 5-7 days for topical treatment; 7 days for oral antibiotics 1
• Clinical response: Improvement typically seen within 3-5 days 3
• Resolution: Complete resolution usually occurs within 2-3 weeks without scarring 4

Common Pitfalls to Avoid

1. Not considering MRSA: Local resistance patterns should guide empiric therapy choices 1
2. Using penicillin V: This is seldom effective for impetigo 5
3. Using topical disinfectants: These are inferior to antibiotics and should not be used 5
4. Inadequate coverage: When both S. aureus and streptococci are suspected, ensure the antibiotic covers both (trimethoprim-sulfamethoxazole alone is inadequate for streptococcal infections) 4
5. Undertreating extensive disease: Systemic antibiotics are preferred for multiple lesions or during outbreaks to reduce transmission 1

Special Populations

• Children in organized sports: Prompt identification and treatment is crucial to prevent outbreaks 1
• Outbreak settings: Systemic antibiotics should be used to help eliminate nephritogenic strains of S. pyogenes and prevent post-streptococcal glomerulonephritis 1

Mupirocin has been shown to be as effective as oral erythromycin with fewer side effects, making it an excellent choice for limited disease 2, 6. For extensive disease, oral antibiotics remain the standard of care to ensure adequate treatment and prevent complications.