What is the recommended treatment course for uncomplicated impetigo?

Treatment Course for Uncomplicated Impetigo

For limited impetigo, topical mupirocin 2% ointment applied three times daily for 5 days is first-line therapy, while extensive disease, systemic symptoms, or facial/oral lesions require oral antibiotics for 7 days. 1

Initial Treatment Selection Based on Disease Extent

Limited Disease (Few Lesions)

• Topical mupirocin 2% ointment applied three times daily for 5 days is the most effective first-line treatment, achieving cure rates 6-fold higher than placebo and superior to oral antibiotics 1, 2
• Topical retapamulin 1% ointment applied twice daily for 5 days is an alternative for patients aged 9 months or older, covering up to 100 cm² in adults or 2% total body surface area in children 3
• The shorter 5-day topical course is adequate and differs from the 7-day requirement for oral therapy 1

Extensive Disease or Treatment Failure

• Switch to oral antibiotics if no improvement after 3-5 days of topical therapy, if lesions are numerous, or if systemic symptoms develop 1
• Oral antibiotics are mandatory for lesions on the face, eyelid, or mouth 1
• During outbreaks, oral therapy is preferred to decrease transmission 1

Oral Antibiotic Regimens (7-Day Duration)

For Presumed Methicillin-Susceptible S. aureus (MSSA)

• Cephalexin: 250-500 mg four times daily for adults; 25-50 mg/kg/day divided into 4 doses for children 1, 3
• Dicloxacillin: 250 mg four times daily for adults; 25-50 mg/kg/day divided into 4 doses for children 1, 3
• Amoxicillin-clavulanate: 875/125 mg twice daily for adults; 25 mg/kg/day (amoxicillin component) in 2 divided doses for children 3, 4

For Suspected or Confirmed MRSA

• Clindamycin: 300-450 mg three to four times daily for adults; 20-30 mg/kg/day in 3 divided doses for children 1, 3
• Trimethoprim-sulfamethoxazole: 1-2 double-strength tablets twice daily for adults; 8-12 mg/kg/day (trimethoprim component) in 2 divided doses for children 1, 3
• Doxycycline: 100 mg twice daily for adults; 2-4 mg/kg/day in 2 divided doses for children >8 years 1, 3
• Initiate empiric MRSA coverage when lesions exhibit purulent drainage, prior treatment has failed, or community CA-MRSA prevalence exceeds 10% 3

Critical Treatment Duration Principles

• Topical antibiotics require 5 days of treatment 1, 2
• Oral antibiotics require 7 days of treatment—do not shorten this course, as it increases failure and recurrence risk 1, 3
• Reassess at 3-5 days; if no improvement occurs, consider MRSA infection, deeper infection, non-compliance, or antibiotic resistance 1

Antibiotics to Avoid

• Penicillin alone is seldom effective and should only be used when cultures confirm streptococci alone, as it lacks adequate coverage against S. aureus 1, 3
• Amoxicillin alone is inadequate because it does not cover S. aureus 3
• Macrolides (erythromycin, azithromycin) show rising resistance rates and should be used only with caution 3, 4
• Cefdinir and other beta-lactams should not be used when MRSA is suspected, documented, or confirmed 3
• Topical clindamycin cream (formulated for acne) lacks FDA indication for impetigo and should not be used 1

Special Population Considerations

Pediatric Patients

• Avoid tetracyclines (doxycycline) in children under 8 years due to risk of permanent dental staining 1, 3
• Cephalexin liquid suspension offers practical dosing advantages over dicloxacillin in children 3

Penicillin Allergy

• Cephalexin may be used in patients with non-immediate penicillin hypersensitivity (cross-reactivity <5%) 3
• In cases of immediate hypersensitivity (anaphylaxis, angioedema, urticaria), use clindamycin instead 3

Pregnancy and Breastfeeding

• Cephalexin is considered safe during pregnancy 1, 3
• Cephalexin, dicloxacillin, trimethoprim-sulfamethoxazole, and doxycycline are acceptable during breastfeeding due to minimal breast milk concentrations 3
• In newborns ≤28 days or infants with jaundice, prematurity, or G6PD deficiency, avoid trimethoprim-sulfamethoxazole and use clindamycin instead 3

Immunocompromised Patients

• Use a lower threshold for oral antibiotics 1
• Monitor closely for treatment failure or deeper infection 1
• Consider longer treatment duration based on clinical response 1

Infection Control Measures (Essential Adjuncts)

• Keep draining lesions covered with clean, dry bandages 1, 3
• Perform regular hand hygiene with soap and water or alcohol-based hand rubs 1, 3
• Do not share personal items that contact skin (towels, razors, linens, sports equipment) 1, 3
• Clean high-touch surfaces (counters, doorknobs, bathtubs) that may contact bare skin 3
• Athletes should be excluded from participation until 24 hours after initiation of effective antimicrobial therapy, and lesions must be covered 1

Management of Treatment Failure

• If mupirocin fails after 5 days, switch to oral antibiotics (dicloxacillin, cephalexin, clindamycin, or amoxicillin-clavulanate) 4
• Consider possible mupirocin resistance, especially in areas with high MRSA prevalence 4
• Obtain cultures from lesions if treatment failure occurs, MRSA is suspected, or in cases of recurrent infections 1, 4
• Rule out deeper infection or alternative diagnosis if clinical presentation is atypical 4
• For recurrent impetigo, consider decolonization strategies using topical nasal mupirocin therapy for S. aureus carriers 1, 4

Common Pitfalls to Avoid

• Do not prescribe oral antibiotics for limited impetigo when topical mupirocin is appropriate and more effective 1, 3
• Do not use cephalexin or any beta-lactam when MRSA is documented or strongly suspected 3
• Do not shorten oral therapy to less than 7 days 1, 3
• Do not use disinfectant solutions as primary therapy, as there is little evidence they improve outcomes 1, 5
• Do not assume cephalexin provides MRSA coverage in regions with high community-acquired MRSA prevalence 3