From the Guidelines
Impetigo should be treated with either topical mupirocin or retapamulin twice daily for 5 days for mild cases, as recommended by the most recent and highest quality study 1.
Treatment Overview
For mild cases of impetigo, topical antibiotics are the preferred treatment option.
- Topical mupirocin or retapamulin applied twice daily for 5 days is effective for treating bullous and nonbullous impetigo 1.
- For more extensive infections or outbreaks, oral antibiotics such as cephalexin or dicloxacillin for 7 days may be necessary 1.
Antibiotic Selection
The choice of antibiotic depends on the severity of the infection and the suspected causative pathogen.
- For patients with numerous lesions or in outbreaks, oral therapy with an agent active against S. aureus is recommended, unless cultures yield streptococci alone, in which case oral penicillin is the recommended agent 1.
- When MRSA is suspected or confirmed, doxycycline, clindamycin, or sulfamethoxazole-trimethoprim (SMX-TMP) is recommended 1.
Additional Recommendations
While treating impetigo, it is essential to keep the affected areas clean with gentle washing using soap and water, avoid scratching to prevent spread, and cover lesions if possible.
- The infection is highly contagious, so avoiding close contact with others, not sharing personal items, and washing hands frequently are crucial measures to prevent the spread of impetigo 1.
Pathogenesis and Complications
Impetigo is typically caused by Staphylococcus aureus or Streptococcus pyogenes bacteria that enter through breaks in the skin, creating honey-colored crusts or fluid-filled blisters.
- Treatment is important to prevent spread to others and rare complications like cellulitis or post-streptococcal glomerulonephritis 1.
From the FDA Drug Label
The efficacy of topical mupirocin ointment in impetigo was tested in two studies. CLINICAL STUDIES In the first, patients with impetigo were randomized to receive either mupirocin ointment or vehicle placebo t.i. d. for 8 to 12 days. Clinical efficacy rates at end of therapy in the evaluable populations (adults and pediatric patients included) were 71% for mupirocin ointment (n=49) and 35% for vehicle placebo (n=51). Pathogen eradication rates in the evaluable populations were 94% for mupirocin ointment and 62% for vehicle placebo There were no side effects reported in the group receiving mupirocin ointment. In the second study, patients with impetigo were randomized to receive either mupirocin ointment t.i. d. or 30 to 40 mg/kg oral erythromycin ethylsuccinate per day (this was an unblinded study) for 8 days. There was a follow-up visit 1 week after treatment ended. Clinical efficacy rates at the follow-up visit in the evaluable populations (adults and pediatric patients included) were 93% for mupirocin ointment (n=29) and 78. 5% for erythromycin (n=28). Pathogen eradication rates in the evaluable patient populations were 100% for both test groups. There were no side effects reported in the mupirocin ointment group. Pediatrics There were 91 pediatric patients aged 2 months to 15 years in the first study described above Clinical efficacy rates at end of therapy in the evaluable populations were 78% for mupirocin ointment (n=42) and 36% for vehicle placebo (n=49). In the second study described above, all patients were pediatric except two adults in the group receiving mupirocin ointment. The age range of the pediatric patients was 7 months to 13 years The clinical efficacy rate for mupirocin ointment (n=27) was 96%, and for erythromycin it was unchanged (78.5%). Mupirocin ointment, 2% is indicated for the topical treatment of impetigo due to: Staphylococcus aureus and Streptococcus pyogenes.
Mupirocin ointment is effective in the treatment of impetigo due to Staphylococcus aureus and Streptococcus pyogenes, with clinical efficacy rates ranging from 71% to 96% in different studies 2. The pathogen eradication rates were also high, ranging from 94% to 100% 2. Mupirocin ointment is indicated for the topical treatment of impetigo due to these pathogens 2.
- Key points:
- Mupirocin ointment is effective in treating impetigo
- Clinical efficacy rates are high
- Pathogen eradication rates are high
- Indicated for topical treatment of impetigo due to Staphylococcus aureus and Streptococcus pyogenes
From the Research
Definition and Types of Impetigo
- Impetigo is a common superficial bacterial skin infection, with a global disease burden of greater than 140 million 3.
- There are two principal types of impetigo: nonbullous (70% of cases) and bullous (30% of cases) 4, 3.
- Nonbullous impetigo, or impetigo contagiosa, is caused by Staphylococcus aureus or Streptococcus pyogenes, and is characterized by honey-colored crusts on the face and extremities 4.
- Bullous impetigo, which is caused exclusively by S. aureus, results in large, flaccid bullae and is more likely to affect intertriginous areas 4.
Diagnosis and Treatment
- The diagnosis of impetigo is usually made clinically, but rarely a culture may be useful 5.
- Treatment includes topical antibiotics such as mupirocin, retapamulin, and fusidic acid 4, 6.
- Oral antibiotic therapy can be used for impetigo with large bullae or when topical therapy is impractical 4, 7.
- Topical antibiotics have been shown to be effective and may be superior to oral antibiotics 6.
- There is a lack of evidence to support disinfection measures to manage impetigo 6.
Complications and Resistance
- Complications of impetigo are rare, but can occur, with the most serious being poststreptococcal glomerulonephritis 4, 3.
- Rising rates of bacterial resistance to standard treatment regimens should inform treatment decisions 4, 3.
- Fusidic acid, mupirocin, and retapamulin cover methicillin-susceptible S. aureus and streptococcal infections 4.
- Clindamycin proves helpful in suspected methicillin-resistant S. aureus infections 4.
Treatment Patterns
- Oral antibiotics are the most common class of medications used to treat impetigo 7.
- There is an opportunity for physicians to take advantage of the equally efficacious topical antibiotics for treating impetigo 7.
- A shift towards topical antibiotics would likely decrease morbidity (resulting from adverse effects) associated with use of oral agents 7.