What is the recommended treatment for a patient with impetigo?

Impetigo Treatment

First-Line Treatment: Topical Mupirocin

For limited impetigo lesions, topical mupirocin 2% ointment applied three times daily for 5-7 days is the most effective first-line treatment, demonstrating superior efficacy to placebo and comparable or better outcomes than oral erythromycin. 1, 2

• Mupirocin is FDA-approved specifically for impetigo caused by Staphylococcus aureus and Streptococcus pyogenes 2
• Clinical cure rates reach 71-93% in evaluable populations, with pathogen eradication rates of 94-100% 2
• Retapamulin is an alternative topical agent if mupirocin is unavailable 1, 3

Critical pitfall: Avoid bacitracin and neomycin—these agents are considerably less effective and should not be used for impetigo 1

When to Switch to Oral Antibiotics

Transition to oral antibiotics if any of the following apply: 1, 3

• Extensive disease (multiple lesions or large affected areas)
• No improvement after 3-5 days of topical therapy
• Lesions on face, eyelid, or mouth
• Systemic symptoms present
• Need to limit spread to others

Oral Antibiotic Selection

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

First-line oral options include: 1, 3

• Dicloxacillin: 250 mg four times daily (adults); 12 mg/kg/day in 4 divided doses (children)
• Cephalexin: 250-500 mg four times daily (adults); 25 mg/kg/day in 4 divided doses (children)
• Amoxicillin-clavulanate: 875/125 mg twice daily (adults); 25 mg/kg/day of amoxicillin component in 2 divided doses (children)

Critical pitfall: Penicillin alone is NOT effective for impetigo as it lacks adequate coverage against S. aureus 1, 3

For Suspected or Confirmed MRSA:

Recommended agents include: 1, 3

• Clindamycin: 300-450 mg three times daily (adults); 10-20 mg/kg/day in 3 divided doses (children)
• Trimethoprim-sulfamethoxazole (TMP-SMX): 1-2 double-strength tablets twice daily (adults); 8-12 mg/kg/day (based on trimethoprim component) in 2 divided doses (children)
• Doxycycline: 100 mg twice daily (adults only—avoid in children under 8 years) 1, 3

Important consideration: TMP-SMX covers MRSA effectively but has inadequate streptococcal coverage; clindamycin covers both MRSA and streptococci, making it the preferred choice when MRSA is suspected 4

Treatment Duration

• Topical therapy: 5-7 days 1
• Oral antibiotics: 5-10 days 1, 3

Special Populations

Pregnant Patients:

• Cephalexin is generally considered safe 3
• Avoid tetracyclines (doxycycline) 3

Children Under 8 Years:

• Avoid all tetracyclines including doxycycline 1, 3
• Clindamycin and TMP-SMX are safe alternatives for MRSA coverage 3

Penicillin-Allergic Patients:

• Clindamycin is the preferred alternative 1

Management of Treatment Failure

If impetigo is refractory to mupirocin: 3

1. Consider mupirocin resistance, especially in high MRSA prevalence areas
2. Obtain cultures to identify pathogen and susceptibilities
3. Initiate oral antibiotics as outlined above
4. Re-evaluate if no improvement after 48-72 hours of oral therapy
5. Consider hospitalization with IV antibiotics (vancomycin for MRSA) if oral therapy fails 3

For recurrent impetigo: Consider decolonization strategies for S. aureus carriers 3

Prevention of Spread

• Keep lesions covered with clean, dry bandages 1
• Maintain good personal hygiene with regular handwashing 1
• Avoid sharing personal items that contact the skin 1

Agents to Avoid

Do NOT use: 1, 5

• Topical clindamycin cream (lacks FDA indication for impetigo; formulated for acne, not bacterial skin infections)
• Topical disinfectants (inferior to antibiotics)
• Penicillin alone (inadequate S. aureus coverage)