What is the recommended treatment for a patient with bacterial impetigo?

Treatment for Bacterial Impetigo

First-Line Treatment Based on Disease Extent

For limited impetigo, topical mupirocin 2% ointment applied twice daily for 5 days is the first-line treatment, while extensive disease requires oral antibiotics such as cephalexin or dicloxacillin for 7 days. 1

Topical Therapy for Limited Disease

• Topical mupirocin 2% ointment applied twice to three times daily for 5 days is highly effective for limited impetigo, achieving cure rates 6-fold higher than placebo 1, 2
• Topical retapamulin ointment (ALTABAX) applied twice daily for 5 days is FDA-approved for impetigo in patients aged 9 months or older, covering up to 100 cm² in adults or 2% total body surface area in pediatric patients 3
• Topical therapy may be superior to oral antibiotics for limited disease and causes fewer side effects, particularly gastrointestinal ones 1, 2
• The treated area may be covered with a sterile bandage or gauze dressing 3

When to Switch to Oral Antibiotics

Oral antibiotics are indicated when: 1, 4

• Numerous lesions are present or disease is extensive
• No response to topical therapy after 3-5 days
• Systemic symptoms are present
• Lesions involve the face, eyelid, or mouth
• During outbreaks to decrease transmission

Oral Antibiotic Selection

For Presumed Methicillin-Susceptible S. aureus (MSSA)

• Cephalexin: 25-50 mg/kg/day divided into 4 doses for children; 250-500 mg four times daily for adults, for 7 days 1, 4
• Dicloxacillin: 25-50 mg/kg/day divided into 4 doses for children; 250 mg four times daily for adults, for 7 days 1, 4
• Co-amoxiclav (amoxicillin-clavulanic acid): An acceptable alternative recommended by IDSA and WHO for 7 days 1

For Suspected or Confirmed MRSA

• Clindamycin: 20-30 mg/kg/day divided into 3 doses for children; 300-450 mg three times daily for adults, for 7 days 1, 4
• Trimethoprim-sulfamethoxazole (SMX-TMP): 8-12 mg/kg/day (based on trimethoprim component) divided into 2 doses for children; 1-2 double-strength tablets twice daily for adults, for 7 days 1, 4
• Doxycycline: 2-4 mg/kg/day divided into 2 doses for children over 8 years old; standard adult dosing for 7 days 1

Critical Treatment Considerations

What NOT to Use

• Penicillin alone is seldom effective and should only be used when cultures confirm streptococci alone, as it lacks adequate coverage against S. aureus 1, 4
• Amoxicillin alone should not be used because it lacks adequate coverage against S. aureus, which is now the predominant causative organism 1
• Topical clindamycin cream (formulated for acne) lacks FDA indication for impetigo and should not be used 4
• Bacitracin and neomycin are considerably less effective and should not be used 4
• Topical disinfectants are inferior to antibiotics and should not be used as primary therapy 1, 2

Treatment Duration

• Topical antibiotics: 5 days 1, 3
• Oral antibiotics: 7 days (not the shorter 5-day course) to avoid treatment failure 1, 4

Special Populations

• Tetracyclines (doxycycline) should be avoided in children under 8 years due to risk of permanent dental staining 1, 4
• Cephalexin can be considered a safe alternative for pregnant patients 1
• For penicillin allergy: Use clindamycin or macrolides, though resistance rates to erythromycin are rising 1, 4
• Avoid cephalosporins if type 1 hypersensitivity (anaphylaxis/hives) to β-lactams 4

High MRSA Prevalence Areas

• In areas with high MRSA prevalence, empiric therapy should cover MRSA until culture results are available 1
• Consider clindamycin or SMX-TMP as first-line oral therapy in these settings 1

Infection Control Measures

To prevent spread and recurrence: 1, 4

• Keep lesions covered with clean, dry bandages
• Maintain good personal hygiene with regular handwashing
• Avoid sharing personal items that contact the skin
• Clean high-touch surfaces that contact bare skin

When to Obtain Cultures

Cultures are indicated for: 4

• Treatment failure after 3-5 days of appropriate therapy
• MRSA is suspected or in high-prevalence areas
• Recurrent infections
• Immunocompromised patients

Special Clinical Situations

Immunocompromised or Diabetic Patients

• Lower threshold for oral antibiotics 1
• Monitor closely for treatment failure or deeper infection 4
• Consider longer treatment duration based on clinical response 4
• Consider hospital admission if extensive disease or systemic signs are present 1

During Outbreaks of Poststreptococcal Glomerulonephritis

• Systemic antimicrobials should be used to help eliminate nephritogenic strains of S. pyogenes from the community 1, 4

Bullous Impetigo

• Apply plain petrolatum ointment and bandages over any open erosions after bullae have deroofed 1
• Systemic antibiotics are typically required due to exclusive S. aureus etiology 1