What is the treatment plan for impetigo?

Treatment Plan for Impetigo

Topical mupirocin 2% ointment is the first-line treatment for limited impetigo lesions, while oral antibiotics are indicated for extensive disease or when topical therapy is impractical. 1, 2

Diagnosis Confirmation

• Impetigo presents in two main forms:
  • Nonbullous impetigo (70% of cases): Characterized by honey-colored crusts on erythematous base, typically affecting face and extremities
  • Bullous impetigo (30% of cases): Presents with large, flaccid bullae, more likely to affect intertriginous areas

Treatment Algorithm

Step 1: Assess Extent of Disease

• Limited lesions (few lesions, small area): Use topical therapy
• Extensive disease (numerous lesions, large area): Use oral antibiotics

Step 2: Select Appropriate Treatment

For Limited Disease:

1. First choice: Topical mupirocin 2% ointment 1, 2, 3

   • Apply three times daily for 5-7 days
   • Clinical improvement should be seen in 85-100% of patients within 3-5 days 4
   • FDA-approved for impetigo due to S. aureus and S. pyogenes 3

2. Alternative topical options:

   • Retapamulin ointment: Apply twice daily for 5 days 5
   • Fusidic acid (where available)

For Extensive Disease or When Topical Therapy is Impractical:

1. First choice oral antibiotics: 1, 2

   • Penicillinase-resistant semisynthetic penicillin (dicloxacillin)
   • First-generation cephalosporin (cephalexin)
   • Amoxicillin-clavulanate

2. For penicillin-allergic patients: 1

   • Clindamycin
   • Macrolides (erythromycin)
   • Doxycycline (for patients >8 years old)

3. For suspected/confirmed MRSA: 2, 6

   • Trimethoprim-sulfamethoxazole (note: inadequate streptococcal coverage)
   • Clindamycin (if susceptible)

Step 3: Treatment Duration

• Topical therapy: 5-7 days 2
• Oral therapy: 7-10 days 2

Comparative Efficacy

• Topical mupirocin has been shown to be as effective as oral erythromycin in treating impetigo, with fewer adverse effects 7, 8
• In clinical trials, mupirocin demonstrated 89.5% clinical success rate at end of therapy compared to 53.2% for placebo 5

Important Considerations

Pitfalls to Avoid

1. Don't use penicillin V alone - It's seldom effective against S. aureus 6
2. Don't use trimethoprim-sulfamethoxazole as a single agent for initial treatment if group A Streptococcus is suspected due to potential resistance 1
3. Don't use topical disinfectants - They are inferior to antibiotics and should not be avoided 6
4. Don't ignore potential resistance - Be aware of increasing prevalence of MRSA, macrolide-resistant streptococcus, and mupirocin-resistant strains 6

Special Populations

• Safety of retapamulin has not been established in patients younger than 9 months 5
• For children, dosing of oral antibiotics should be weight-appropriate

Prevention Measures

• Good hygiene practices
• Avoid sharing personal items
• Limit exposure to infected individuals
• Prompt identification and treatment of cases to prevent spread 1

Follow-up

• Re-evaluate patients in 24-48 hours if using tetracyclines or trimethoprim-sulfamethoxazole to verify clinical response 2
• Most cases resolve within 2-3 weeks without scarring 6
• Complications are rare, with poststreptococcal glomerulonephritis being the most serious (rate <1 case/1,000 population per year) 1, 2