Approach Considerations
Treatment of impetigo typically involves local wound care along with antibiotic therapy. Antibiotic therapy for impetigo may be with a topical agent alone or a combination of systemic and topical agents.
Gentle cleansing, removal of the honey-colored crusts of nonbullous impetigo using antibacterial soap and a washcloth, and frequent application of wet dressings to areas affected by lesions are recommended. Good hygiene with antibacterial washes, such as chlorhexidine or sodium hypochlorite baths, may prevent the transmission of impetigo and prevent recurrences, but the efficacy of this has not been proven.
For antibiotic therapy, the chosen agent must provide coverage against both Staphylococcus aureus and Streptococcus pyogenes. The prevalence of methicillin-resistant S aureus (MRSA) and macrolide-resistant Streptococcus has changed empiric treatment options for impetigo. MRSA was responsible for 78% of all community staphylococcal-related skin and soft tissue skin infections in a multicenter US study. [35]
Community-acquired MRSA (CA-MRSA) infection most commonly manifests as folliculitis or abscess because it possesses the Panton-Valentine leukocidin gene rather than the exfoliative toxin gene. CA-MRSA is thus less likely to cause exfoliative infections such as impetigo and more likely to cause suppurative infections such as abscesses. [36] Therefore, beta-lactam drugs remain an appropriate initial empiric choice for systemic antibiotics for the treatment of impetigo. [37] However, the continued increased presence of CA-MRSA may limit the utility of these agents. In this situation, trimethoprim/sulfamethoxazole, clindamycin, or doxycycline in children older than 8 years can be used if the isolate is susceptible. [37, 38]
Topical mupirocin or retapamulin is adequate treatment for single lesions of nonbullous impetigo or small areas of involvement. Systemic antibiotics are indicated for nonbullous impetigo with extensive involvement, in athletic teams, childcare clusters, multiple family members, or for bullous impetigo. [27, 37]
In patients with bullous impetigo who present to the emergency department with large areas of involvement resulting in denuded skin from ruptured bullae, management also includes intravenous fluid resuscitation. Fluid is given at a volume and rate similar to standard volume replacement for burns.
Inpatient care is required for patients with impetigo who have widespread disease or for infants at risk of sepsis and/or dehydration due to skin loss. If inpatient care is warranted in the child with untreated impetigo, contact isolation is recommended.
A clinical guideline summary from the Infectious Diseases Society of America that includes recommendations on impetigo, Practice guidelines for the diagnosis and management of skin and soft-tissue infections, may be helpful.
Topical Antibiotic Treatment
Topical antibiotic therapy is considered the treatment of choice for individuals with uncomplicated localized impetigo. Topical therapy eradicates isolated disease and limits the individual-to-individual spread. The topical agent is applied after removal of the infected crusts and debris with soap and water. Disadvantages of topical treatment are that it cannot eradicate organisms from the respiratory tract and that applying topical medications to extensive lesions is difficult.
Mupirocin
Mupirocin ointment (Bactroban) has been used for both the lesions and to clear chronic nasal carriers. Although it is expensive, it has been shown to be superior to topical polymyxin B and neomycin [39, 40] and to be equally effective as oral cephalexin. Both mupirocin and oral cephalexin are superior to bacitracin. [41] It is applied to the affected area 2 times daily. A 5-day course is usually standard, although few large studies have been performed to verify this as the most effective approach. Unfortunately, S aureus and MRSA resistance to mupirocin has emerged at estimated rates ranging from 5-10%. [39, 42]
Retapamulin
Retapamulin (Altabax) ointment is in a relatively new class of topical antimicrobials. It is approved by the US Food and Drug Administration (FDA) for treatment of localized impetigo caused by S pyogenes and methicillin-susceptible S aureus in children older than 9 months. [43, 44] It is applied twice daily for 5 days. It is not for mucosal use; epistaxis has been reported with nasal mucosa application.
Retapamulin has an excellent spectrum of activity, surpassing the bacterial spectrum of mupirocin. [39, 45, 46] It has been shown to preserve its activity against bacteria that were resistant to multiple antibiotic drugs, such as methicillin, erythromycin, fusidic acid, mupirocin, azithromycin, and levofloxacin. [47, 48] The spectrum of retapamulin also includes erythromycin-resistant S pyogenes, fusidic acid–resistant and mupirocin-resistant S aureus, and MRSA (including P-VL–positive strains). [6]
In more than 1900 patients evaluated in several comparative studies, retapamulin has been demonstrated to be as effective as topical fusidic acid and oral cephalexin, with a low rate of adverse events. [39] In another study, retapamulin 1% ointment showed more efficacy than fusidic acid 2% ointment for the treatment of impetigo. [49]
Fusidic acid
Topical sodium fusidate (fusidic acid), currently not available in the United States, has been recognized as first-line therapy in Europe and other parts of the world. [7, 50] High resistance rates have been reported with the use of fusidic acid, however, ranging from 32.5-50%. [7, 49, 51, 52, 53]
A Swedish study of 38 patients with impetigo showed resistance of S aureus to fusidic acid in 75% of bullous cases and 32% of nonbullous ones. The authors recommended restricted use of fusidic acid in order to limit the rising levels of resistance. [54]
Other topical antibiotics
Other topical antibiotics have been reported to have some benefit for the treatment of impetigo. Clindamycin (cream, lotion, and foam) is useful in several MRSA infections. [55, 56] Gentamicin ointment or cream has been used in many countries for some gram-positive staphylococcal infections, including impetigo and pyoderma. Its use is precluded by the potential development of ear and kidney toxicity. [39, 55]
Hydrogen peroxide 1% cream, available in many countries, has demonstrated comparable bactericidal activity and longer duration of action than hydrogen peroxide 1% aqueous solution in vitro. It is applied 2-3 times a day on the affected area for a maximum of 3 weeks. Although the potential for sensitization is low, hypersensitivity reactions have been reported to other ingredients in the commercially available product. [55, 57]
Tetracycline has been used for localized impetigo. It is not widely prescribed because of the potential risk of skin photosensitivity reactions [3, 55] and because it is contraindicated in children younger than 8 years.
Drugs such as sulfanilamide, nitrofurazone, and silver sulfadiazine, which are widely used for the treatment of burns, are not currently used for the treatment of impetigo. Because of their antibacterial spectrum and proven efficacy and tolerability, these drugs may need to be considered in the future for the treatment of impetigo and other community-acquired skin infections. [39, 55]
FDA approved ozenoxacin based on two phase 3 multicenter, randomized double-blind placebo-controlled studies. Both phase 3 pivotal studies demonstrated ozenoxacin cream 1% applied topical twice daily for 5 days, was superior to placebo on both the clinical and bacteriological endpoints. Patients (N=723) ≥2 months old with an affected body surface area of up to 100 cm2, and not exceeding 2% for patients aged 2 months to 11 years, were randomized to ozenoxacin or placebo. Clinical success was defined as no need for additional antimicrobial therapy of the baseline affected areas and absence or reduction in clinical signs and symptoms assessed at the end of therapy.
In both studies, a higher percentage of patients had clinical success in the ozenoxacin group compared to the placebo group (Trial 1: 34.8% vs. 19.2%; Trial 2: 54.4% vs. 37.9%). The success rates for ozenoxacin were significantly different than placebo in both trials.
Ozenoxacin produced more rapid microbiological clearance than placebo after 2 days of therapy. The rapid clinical response of ozenoxacin could be clinically beneficial in terms of reducing the likelihood of disease spread to other parts of the body or to other persons; this is particularly important in the pediatric population. Data from a pooled analysis of the 2 trials demonstrated ozenoxacin to be a rapid and effective new treatment for impetigo. [58, 59]
Future promising topical treatments on the horizon include topical minocycline foam, [60] which is highly effective against MRSA.
Systemic Antibiotic Treatment
Infections that are widespread, complicated, or are associated with systemic manifestations (outbreaks of poststreptococcal glomerulonephritis) are usually treated with antibiotics that have gram-positive bacterial coverage. Systemic therapy is also recommended if multiple incidents of pyoderma occur within daycare, family, or athletic team settings.
Beta-lactamase‒resistant antibiotics (eg, cephalosporins, amoxicillin-clavulanate, dicloxacillin) are recommended as S aureus isolates from impetigo are usually methicillin-susceptible. [37] Cephalexin appears to be the drug of choice for oral antimicrobial therapy in children.
Community-acquired MRSA has become widespread. [35, 61] If MRSA is suspected, alternative antibiotics include clindamycin, trimethoprim/sulfamethoxazole, and doxycycline in patients older than 8 years. [37] Empiric treatment depends on the prevalence and sensitivities of MRSA in a particular geographic region. [62] Physicians should be aware of local resistance patterns.
Erythromycin and clindamycin are alternatives in patients with penicillin hypersensitivity. Macrolide resistance has been increasing in the United States. Thus, avoid treatment of impetigo with erythromycin in geographic regions that are known to have a high resistance rate. Group A beta hemolytic streptococci (GABHS) and S aureus resistance to clindamycin has also been reported.
Deterrence and Prevention
Children with impetigo should avoid close contact with other children if possible. Current recommendations call for the exclusion of children with impetigo from school or day care for 24 hours after the initiation of antibiotics. This recommendation primarily assumes that GABHS is the cause. If S aureus is documented to be the etiology, exclusion from school or day care is not necessary.
Inspect household members for impetiginous lesions. With neonatal impetigo, also evaluate hospital nursery staff and household members for pyodermas or asymptomatic bacterial carrier states. Failure to treat other infected persons may result in continued transmission.
Treat traumatized skin with mupirocin because this has been shown to decrease the rates of impetigo spread. Treat preexisting underlying skin diseases, such as atopic dermatitis. Antihistamines and topical steroids help decrease scratching. Treating the underlying disease has also been shown to decrease the pathogen count on the skin.
Teach good personal hygiene. For example, keep nails short and clean and wash hands frequently with antibacterial soap and water or waterless antibacterial cleansers. Advise patients about improving environmental conditions through the addition of air conditioning and by keeping surroundings clean.
For patients with recurrent impetigo, asymptomatic family members, and S aureus nasal carriers, prescribe 2% mupirocin cream or ointment (Bactroban) for application inside nostrils 3 times per day for 5 days each month to reduce colonization in the nose. Retapamulin may replace mupirocin for this indication, although data are needed to support its use in this setting. Patients who are chronic nasal carriers can also be treated with clindamycin or rifampin plus dicloxacillin.
Polymerase chain reaction to detect the mecA gene has become an effective tool for the screening for MRSA colonization upon hospital admission. However, screening has not been shown to significantly reduce transmission of and infection with MRSA. [6]
A study by Romani et al that conducted a trial of mass drug administration for scabies control in Fiji reported that mass drug administration, particularly the administration of ivermectin, was efficacious for the control of scabies and impetigo. [63, 64]
Consultations and Long-Term Monitoring
The need for consultation is determined by the extent of involvement and the age of the patient. Neonates with bullous impetigo may require a consultation with a neonatologist.
Recurrent disease should trigger a specialist consult. Consult a nephrologist if signs and symptoms of acute glomerulonephritis develop.
Follow-up is important to ensure complete clearing of lesions. Schedule a follow-up visit within 1 week. If the lesions have not improved, check the bacterial culture and sensitivity results, look for MRSA, and prescribe alternative antibiotics accordingly. If the patient was treated with oral antibiotics, prescribe alternative antibiotics depending on bacterial culture and sensitivity results.
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Bullous impetigo with circumscribed lesions with a thin collarette of scale.
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Bullous impetigo on the buttocks. Courtesy of Medical University of South Carolina, Department of Dermatology.
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Following dermabrasion, this patient developed nonbullous impetigo in the same area as several herpes simplex lesions. Note the grouped vesicles which are classic for herpetic lesions, as well as additional crusted pink plaques. Concurrent bacterial impetigo can often be seen with herpes simplex and aerobic bacterial cultures are important to identify secondary impetigo.
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A nummular eczema lesion on the knee, impetiginized with Staphylococcus aureus.
