Plain language summary
Interventions for the skin infection impetigo
Impetigo causes blister-like sores. The sores can fill with pus and form scabs, and scratching can spread the infection. Impetigo is caused by bacteria. It is contagious and usually occurs in children. It is the most common bacterial skin infection presented by children to primary care physicians. Treatment options include topical antibiotics (antibiotic creams), oral antibiotics (antibiotics taken by mouth), and disinfectant solutions. There is no generally agreed standard treatment, and the evidence on what intervention works best is not clear.
We identified 68 randomised controlled trials comparing various treatments for impetigo. Altogether, these studies evaluated 26 oral treatments and 24 topical treatments, including placebo, and results were described for 5708 participants.
Overall, topical antibiotics showed better cure rates than topical placebo.
Two antibiotic creams, mupirocin and fusidic acid, are at least as effective as oral antibiotics where the disease is not extensive. There was no clear evidence that either of these most commonly studied topical antibiotics was more effective than the other.
Topical mupirocin was superior to the oral antibiotic, oral erythromycin.
We found that the oral antibiotic, oral penicillin, is not effective for impetigo, while other oral antibiotics (e.g. erythromycin and cloxacillin) can help.
It is unclear if oral antibiotics are superior to topical antibiotics for people with extensive impetigo.
There is a lack of evidence to suggest that using disinfectant solutions improves impetigo. When 2 studies with 292 participants were pooled, topical antibiotics were significantly better than disinfecting treatments.
Reported side-effects for topical treatments were mild and low in frequency; the treatments sometimes resulted in itching, burning, or staining. Oral antibiotics produced gastrointestinal complaints, such as nausea and diarrhoea, in 2% to 30% of participants, depending upon the specific antibiotic.
Worldwide, bacteria causing impetigo show growing resistance rates for commonly used antibiotics. For a newly developed topical treatment, retapamulin, no resistance has yet been reported.
Résumé simplifié
Interventions dans l'impétigo (infection cutanée)
L'impétigo provoque des plaies semblables à des cloques. Ces plaies peuvent contenir du pus et former des croûtes et le fait de se gratter entraîne la propagation de l'infection. Des bactéries sont à l'origine de l'apparition de l'impétigo. Il est particulièrement contagieux et touche généralement les enfants. Il s'agit de l'infection bactérienne cutanée la plus couramment diagnostiquée chez les enfants par les médecins généralistes. Les options de traitement incluent des antibiotiques topiques (crèmes antibiotiques), des antibiotiques oraux (antibiotiques avalés par la bouche) et des solutions désinfectantes. En général, il n'existe aucun traitement standard homologué et aucune preuve relative à l'intervention la plus efficace n'a été établie avec certitude.
Nous avons identifié 68 essais contrôlés randomisés comparant plusieurs traitements de l'impétigo. Toutes ces études ont évalué 26 traitements oraux et 24 traitements topiques, y compris un placebo, et les résultats concernant 5 708 participants ont été examinés.
Dans l'ensemble, les antibiotiques topiques ont affichés de meilleurs taux de guérison qu'un placebo topique.
Deux crèmes antibiotiques, la mupirocine et l'acide fusidique, sont au moins aussi efficaces que les antibiotiques oraux en cas de maladie bénigne. Aucune preuve claire n'a permis de démontrer que l'un de ces antibiotiques topiques les plus couramment étudiés était plus efficace qu'un autre.
La mupirocine était plus efficace qu'un antibiotique oral, l'érythromycine orale.
Nous avons trouvé qu'un antibiotique oral, la pénicilline orale, est inefficace pour le traitement de l'impétigo, contrairement à d'autres antibiotiques oraux qui pourraient aider (par ex. : l'érythromycine et la cloxacilline).
On ignore si les antibiotiques oraux sont supérieurs aux antibiotiques topiques chez les personnes souffrant d'un impétigo sévère.
Les preuves sont insuffisantes pour démontrer que les solutions désinfectantes atténue l'impétigo. Lors du regroupement de 2 études composées de 292 participants, les antibiotiques topiques se sont révélés beaucoup plus efficaces que les traitements désinfectants.
La fréquence des effets secondaires signalés pour les traitements topiques était légère et faible ; les traitements provoquaient parfois des démangeaisons, des brûlures ou des tâches. Les antibiotiques oraux entraînaient des maladies gastro-intestinales, comme des nausées et des diarrhées, chez 2 à 30 % des participants en fonction de l'antibiotique spécifique.
Partout dans le monde, les bactéries à l'origine de l'impétigo sont de plus en plus résistantes aux antibiotiques couramment prescrits. Dans le cas d'un traitement topique récemment mis au point, la rétapamuline, aucune résistance n'a encore été signalée.
Notes de traduction
Recherches parrainées
Le parrainage industriel ou l'organisation de l'essai était mentionné(e) dans 20 essais (29 %) : 5 études sur la mupirocine (Goldfarb 1988 ; Mertz 1989 ; Rist 2002 ; Wainscott 1985 ; White 1989), 2 sur le cefdinir (Tack 1997 ; Tack 1998), 2 sur le céfadroxil (Beitner 1996 ; Hains 1989), 2 sur l'azithromycine (Daniel 1991a ; Daniel 1991b), 2 sur le cefditoren (Bucko 2002a ; Bucko 2002b) ; 2 sur la rétapamuline (Koning 2008 ; Oranje 2007) ; 1 sur l'amoxicilline plus l'acide clavulanique (Jaffe 1985), la céfalexine (Dillon 1983 ; Giordano 2006), la clindamycine (Blaszcyk 1998) et l'acide fusidique (Sutton 1992). Cinq essais (9 %) ont été parrainés par d'autres organisations. Pour les 48 essais restants (67 %), aucune déclaration de parrainage ou de financement n'a été indiquée (voir Tableau 2 « Parrainage ou financement déclaré »).
Traduit par: French Cochrane Centre 10th April, 2012
Traduction financée par: Ministère du Travail, de l'Emploi et de la Santé Français
Ringkasan bahasa mudah
Intervensi untuk jangkitan kulit impetigo.
Impetigo menyebabkan kudis yang berupa lepuh. Kudis boleh mengandungi nanah dan membentuk kuping, dan penggaruan kulit boleh merebakkan jangkitan. Impetigo disebabkan oleh bakteria. Ia mudah berjangkit dan biasanya berlaku pada kanak-kanak. Ia adalah jangkitan kulit bakteria yang paling biasa ditunjukkan oleh kanak-kanak kepada doktor penjagaan utama. Pilihan rawatan termasuk antibiotik topikal (krim antibiotik), antibiotik oral (antibiotik diambil melalui mulut), dan larutan disinfektan. Tiada rawatan standard umum yang disetujui dan bukti mengenai intervensi yang berfungsi tidak jelas.
Kami telah mengenal pasti 68 ujian terkawal rawak yang membandingkan pelbagai rawatan untuk impetigo. Semua kajian ini menilai 26 rawatan oral dan 24 rawatan topikal, termasuk plasebo, dan keputusan telah diperolehi daripada 5708 peserta.
Secara keseluruhannya, antibiotik topikal menunjukkan kadar penyembuhan yang lebih baik daripada plasebo topikal.
Dua krim antibiotik, mupirocin dan asid fusidic, sekurang-kurangnya berkesan sebagai antibiotik oral di mana penyakit ini tidak merebak dengan luas. Tidak ada bukti jelas bahawa salah satu daripada kedua-dua antibiotik topikal paling biasa dikaji adalah lebih berkesan daripada yang lain.
Mupirocin topikal lebih berkesan daripada antibiotik oral, erythromycin oral.
Kami mendapati bahawa antibiotik oral, penicillin oral, tidak berkesan untuk impetigo, manakala antibiotik oral lain (misalnya erythromycin dan cloxacillin) boleh membantu.
Ia adalah tidak jelas samada antibiotik oral adalah lebih berkesan daripada antibiotik topikal untuk orang dengan impetigo yang merebak luas.
Terdapat kekurangan bukti yang menunjukkan bahawa penggunaan larutan disinfektan boleh memulihkan impetigo. Apabila 2 kajian dengan 292 peserta telah dikumpulkan, antibiotik topikal adalah jauh lebih baik daripada rawatan pembasmi kuman.
Kesan sampingan untuk rawatan topikal dilaporkan lebih ringan dan tidak begitu kerap; rawatan kadang-kadang menyebabkan kegatalan, rasa panas atau pengotoran. Antibiotik oral menyebabkan aduan gastrousus seperti loya dan cirit-birit, dalam 2% kepada 30% daripada peserta, bergantung kepada antibiotik tertentu.
Di seluruh dunia, bakteria yang menyebabkan impetigo menunjukkan kadar rintangan yang semakin meningkat untuk antibiotik yang biasa digunakan. Untuk rawatan topikal yang baru digunakan retapamulin, tiada rintangan telah dilaporkan.
Catatan terjemahan
Diterjemahkan oleh Ng Chia Shyn (International Medical University). Disunting oleh Tuan Hairulnizam Tuan Kamauzaman (Universiti Sains Malaysia). Untuk sebarang pertanyaan berkaitan terjemahan ini sila hubungi Ng.ChiaShyn@student.imu.edu.my.
Background
Description of the condition
Biology and symptoms
Impetigo or impetigo contagiosa is a contagious superficial bacterial skin infection most frequently encountered in children. It is typically classified as either primary (e.g. direct bacterial invasion of previously normal skin), secondary, or common impetigo (where the infection is secondary to some other underlying skin disease that disrupts the skin barrier, such as scabies or eczema). Impetigo is also classified as bullous or non-bullous impetigo. Bullous impetigo simply means that the skin eruption is characterised by bullae (blisters). The term 'impetigo contagiosa' is sometimes used to mean non-bullous impetigo, and at other times it is used as a synonym for all impetigo.
Non-bullous impetigo is the most common form of impetigo. The initial lesion is a thin-walled vesicle on previously normal skin that rapidly ruptures. It then leaves superficial erosion covered with yellowish-brown or honey-coloured crusts. The crusts eventually dry, separate, and disappear, leaving a red mark that heals without scarring. The most frequently affected areas are the face and limbs. The lesions are sometimes painful. Usually, there are no systemic symptoms such as fever, malaise, or anorexia. Swelling of the lymph nodes draining the infected area of skin is common. It is believed that, in most cases, spontaneous resolution may be expected within two to three weeks without treatment but more prompt resolution occurs with adequate treatment. Diagnostic confusion can occur with a variety of skin disorders including shingles, cold sores, cutaneous fungal infections, and eczema (Hay 1998; Resnick 2000). Pyoderma is sometimes used as a synonym for impetigo in tropical countries. This is usually to denote streptococcal, as opposed to staphylococcal, impetigo.
Bullous impetigo is characterised by larger bullae or blisters that rupture less readily and can persist for several days. Usually there are fewer lesions and the trunk is affected more frequently than in non-bullous impetigo. Diagnostic confusion can occur with thermal burns, blistering disorders (e.g. bullous pemphigoid), and Stevens Johnson syndrome.
Causes
Staphylococcus aureus (S. aureus) is considered to be the main bacterium that causes non-bullous impetigo. However, Streptococcus pyogenes (S. pyogenes), or both S. pyogenes and S. aureus, are sometimes isolated from the skin. In moderate climates, staphylococcal impetigo is more common, whereas in warmer and more humid climates, the streptococcal form predominates. In moderate climates, the relative frequency of S. aureus infections has also changed with time (Dagan 1993). It was predominant in the 1940s and 1950s, after which Group A streptococci became more prevalent. In the past two decades, S. aureus has become more common again. Bullous impetigo is always caused by S. aureus.
Secondary impetigo may occur as a complication of many dermatological conditions (notably eczema). The eruption appears clinically similar to non-bullous impetigo. Usually S. aureus is involved. The underlying skin disease may improve with successful treatment of the impetigo, and the converse may also be true.
Complications of non-bullous impetigo are rare, but local and systemic spread of infection can occur that may result in cellulitis, lymphangitis, or septicaemia. Non-infectious complications of S. pyogenes infection include guttate psoriasis, scarlet fever, and glomerulonephritis (an inflammation of the kidney that can lead to kidney failure). It is thought that most cases of glomerulonephritis result from streptococcal impetigo rather than streptococcal throat infection, and this has always been an important rationale for antibiotic treatment. The incidence of acute glomerulonephritis has declined rapidly over the last few decades. Baltimore 1985 stated that the risk of developing glomerulonephritis is not altered by treatment of impetigo; however, certain subtypes of Group A streptococci are associated with a much greater risk (Dillon 1979b).
Epidemiology
In the Netherlands, most people with impetigo consult their general practitioner and only approximately 1% of the cases are referred to a dermatologist (Bruijnzeels 1993). Although the incidence of impetigo in general practice has been declining, recent data show an increase in consultations for impetigo (Koning 2006; Van den Bosch 2007). Impetigo is still a common disease particularly in young children. It is the third most common skin disorder in children after dermatitis/eczema and viral warts (Bruijnzeels 1993; Dagan 1993; Mohammedamin 2006). Impetigo is the most common skin infection that is presented in general practice by children aged one to four years of age (Mohammedamin 2006). In British general practice, 2.8% of children aged 0 to 4 and 1.6% aged 5 to 15 consult their GP about impetigo each year (McCormick 1995). In the Netherlands in the late 1980s, the consultation rate was 1.7% of all children under 18 years of age; this increased to 2.1% in 2001 (Koning 2006). Peak incidence occurs between the ages of one and eight years (Koning 2006). In some tropical or developing countries the incidence of impetigo seems to be higher than elsewhere (Canizares 1993; Kristensen 1991).
Description of the intervention
Management options for impetigo include the following:
no pharmacological treatment, waiting for natural resolution, hygiene measures;
topical disinfectants (such as saline, hexachlorophene, povidone iodine, and chlorhexidine);
topical antibiotics (such as neomycin, bacitracin, polymyxin B, gentamycin, fusidic acid, mupirocin, retapamulin, or topical steroid/antibiotic combination); and
systemic antibiotics (such as penicillin, (flu)cloxacillin, amoxicillin/clavulanic acid, erythromycin, and cephalexin).
The aim of treatment includes resolving the soreness caused by lesions and the disease's unsightly appearance (especially on the face), as well as preventing recurrence and spread to other people. An ideal treatment should be effective, cheap, easy to use, and accepted by people. It should be free from side-effects, and it should not contribute to bacterial resistance. For this reason, antibiotics should not have an unnecessarily broad spectrum (Espersen 1998; Smeenk 1999), and if a topical antibiotic is used, it should, preferably, not be one which may be needed for systemic use (Carruthers 1988; Smeenk 1999).
Waiting for natural resolution could be acceptable if the natural history were known and benign. Impetigo is considered to be self-limiting by many authors (Hay 1998; Resnick 2000). However, there are no robust data on the natural history of impetigo. Reported cure rates of placebo creams vary from 8% to 42% at 7 to 10 days (Eells 1986; Ruby 1973). Topical cleansing used to be advised in the 1970s as an alternative for antibiotic treatment, but this was later said to be no more effective than placebo (Dagan 1992). Guidelines and treatment advice often do not mention topical cleansing as a treatment because the main concern is preventing the spread of the infection to other children.
A choice has to be made between topical and systemic antibiotic treatment, although in some situations clinicians prescribe both topical and systemic antibiotics. An advantage of the use of topical antibiotics is that the drug can be applied where it is needed, avoiding systemic side-effects such as gastrointestinal upset. Also, compliance may be better (Britton 1990).
The disadvantages of using topical antibiotics include the risks of developing bacterial resistance and sensitisation, e.g. developing an allergic contact dermatitis to one of the constituents of the topical preparation (Carruthers 1988; Smeenk 1999). This is especially common with the older antibiotics, such as gentamycin, bacitracin, and neomycin (Smeenk 1999). Some preparations (e.g. tetracycline) can cause staining of the skin and clothes.
Staphylococcal resistance against penicillin and erythromycin is common (Dagan 1992). Bacterial resistance against the newer topical antibiotics, such as mupirocin ointment and fusidic acid ointment, is increasing (Alsterholm 2010; de Neeling 1998). Another advantage of the newer topical antibiotics is that mupirocin is never, and fusidic acid not often, used systemically.
How the intervention might work
All treatment options listed above aim to either eradicate or prevent growth of the bacteria.
Why it is important to do this review
Guidelines concerning treatment vary widely - some recommend oral antibiotic treatment, others local antibiotic treatment or even just disinfection in mild cases (Hay 1998; Resnick 2000) - so clinicians have many treatment options. The evidence on what works best is not clear. There is potential conflict between what is in the best interest of the individual and what would best benefit the community in terms of cost and the increase in antibiotic resistance.
Objectives
To assess the effects of treatments for impetigo, including waiting for natural resolution.
Methods
Criteria for considering studies for this review
Types of studies
We included randomised controlled trials.
Types of participants
We included people who have impetigo or impetigo contagiosa diagnosed by a medically trained person (and preferably confirmed by bacterial culture). We recorded whether or not bacterial culture was performed. The diagnosis could be either non-bullous or bullous impetigo. Studies using a broader diagnostic category such as 'bacterial skin infections' or 'pyoderma' were eligible if a specific subgroup with impetigo could be identified, for which the results were separately described. Studies on secondary impetigo or impetiginised dermatoses were included.
Types of interventions
We included any program of topical or systemic (oral, intramuscular, or intravenous) treatment, including antibiotics, disinfectants, or any other intervention for impetigo, such as 'awaiting natural response'. We excluded studies that only compared different dosages of the same drug.
Types of outcome measures
Primary outcomes
1) Cure as defined by clearance of crusts, blisters, and redness as assessed by the investigator.
2) Relief of symptoms such as pain, itching, and soreness as assessed by participants.
Secondary outcomes
1) Recurrence rate.
2) Adverse effects such as pain, allergic sensitisation, and complications.
3) Development of bacterial resistance.
Search methods for identification of studies
We aimed to identify all relevant randomised controlled trials (RCTs) regardless of language or publication status (published, unpublished, in press, or in progress).
Electronic searches
We updated our searches of the following databases on 27 July 2010:
the Cochrane Skin Group Specialised Register using the following search terms: (impetig* or pyoderma or ((staphylococc* or streptococc*) and skin and infection*)) and (therap* or treatment* or intervention*);
the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library using the search strategy in Appendix 1;
MEDLINE (from 2005 to the present) using the search strategy in Appendix 2;
EMBASE (from 2007 to the present) using the search strategy in Appendix 3; and
LILACS (Latin American and Caribbean Health Science Information database, from 1982 to the present) using the search strategy in Appendix 4.
Please note: The UK and US Cochrane Centres have an ongoing project to systematically search MEDLINE and EMBASE for reports of trials which are then included in the CENTRAL database. Searching has currently been completed in MEDLINE, from inception to 2004 and in EMBASE, from inception to 2006. Further searches of these two databases to cover the years not searched by the UK and US Cochrane Centres for CENTRAL were undertaken for this review as described above.
A final prepublication search for this review was undertaken on 16 August 2011. Although it has not been possible to incorporate RCTs identified through this search within this review, relevant references are listed under Studies awaiting classification. They will be incorporated into the next update of the review.
Ongoing Trials
We updated our searches of the following ongoing trials databases on 3 August 2010, using the terms 'impetigo' and 'pyoderma':
Searching other resources
Handsearching
We handsearched the Yearbook of Dermatology (1938 to 1966) and the Yearbook of Drug Therapy (1949 to 1966) for the pre-PubMed era.
References from published studies
We checked references from published studies, including secondary review articles, for further studies.
Unpublished literature
We corresponded with authors and pharmaceutical companies to search for unpublished studies and grey literature.
Language
We did not apply any language restrictions.
Data collection and analysis
Selection of studies
Two authors (JCvdW and SK or RvdS) independently read all abstracts or citations of trials. If one of the authors thought the article might be relevant, a full copy of the article was acquired for further data collection. The reasons for exclusion were recorded for every excluded abstract or citation. Only full reports were included. Two authors independently screened all full-copy articles (LvSS, SK, RvdS, JCvdW). The articles were selected according to the inclusion criteria. Reasons for exclusion were recorded on a specially-designed registration form (see the 'Characteristics of excluded studies' table). In the case of doubt, the opinion of a third author was obtained. Many trials studied a range of (skin) infections including impetigo. Frequently, the results of the subgroup of impetigo participants were not reported separately. In these studies, provided they were published in the last 10 years, we contacted trial authors and asked them to provide the results of the subgroup of impetigo participants. We obtained data in this way in only two instances (Blaszcyk 1998; Claudy 2001).
Data extraction and management
Two authors (ADM and CCB), using a pre-piloted data abstraction form, carried out the full data extraction. The form contained key elements such as time and setting of the study, participant characteristics, bacterial characteristics, type of interventions, outcomes, and side-effects. We resolved disagreements with the help of a third author (SK).
For this update, RvdS and JCvdW carried out data extraction from newly included papers. When studies assessed outcome measures more than once, we included the assessment that was nearest to one week after the start of therapy. When studies had more than two arms and two of these arms were different dosages of the same drug, we combined these arms.
Assessment of risk of bias in included studies
Assessment of methodological quality
Two independent authors (JCvdW, RvdS and/or AV) assessed the methodological quality of all trials according to the updated guidelines (Higgins 2008). Because we could not read the Japanese study by Ishii 1977, this 'Risk of bias' table was completed by Tetsuri Matsumura. The two studies on which authors of this review were co-authors (Koning 2003; Koning 2008) were assessed by other authors. The items that were addressed are shown in the 'Risk of bias' table. For feasibility reasons, the methodological quality assessment was not performed under masked conditions. There is no consensus over whether assessment should be done blinded for authors, institutions, journal, or publication year (Jadad 1998).
Unit of analysis issues
In the case of studies with more than two treatment arms, we deemed that pooling these studies under separate comparisons, without adjustment, would result in unit-of-analysis errors (overcounting). Should this have occurred, the problem was to be solved by dividing the group size by the number of comparisons.
Assessment of heterogeneity
We used the I² statistic to assess statistical heterogeneity, with I² statistic > 50% regarded as substantial heterogeneity.
Data synthesis
Where there was no statistical evidence of heterogeneity we used the fixed-effect model to estimate effects. Otherwise, we used the random-effects model. For dichotomous outcomes we reported risk ratios with 95% confidence intervals.
Sensitivity analysis
We prespecified the following factors for sensitivity analyses:
the quality of the studies;
whether there was observer blinding;
whether there was just a clinical diagnosis or bacterial swab confirmation;
primary versus secondary impetigo;
bullous versus non-bullous; and
staphylococcal or streptococcal predominance.
During the update, we decided that an overall quality score per study was not useful. Furthermore, most trials were observer-blind, took bacterial swabs, studied primary impetigo, and had staphylococcal predominance. Sensitivity analyses for these items were, therefore, not possible.
When we analysed the data we decided to consider the results for bullous and non-bullous impetigo separately.
Discussion
Summary of main results
Overall, topical antibiotics showed better cure rates than topical placebo. No differences were found between the two most studied topical antibiotics: mupirocin and fusidic acid. Topical mupirocin was superior to oral erythromycin. In most other comparisons, topical and oral antibiotics did not show significantly different cure rates, nor did most trials comparing oral antibiotics. Penicillin V was inferior to erythromycin and cloxacillin, and there is a lack of evidence to suggest that using disinfectant solutions improves impetigo.
The reported number of side-effects was low. Oral antibiotic treatment caused more side-effects, especially gastrointestinal ones, than topical treatment. A striking finding is that the trials comparing erythromycin with mupirocin recorded more (gastrointestinal) side-effects in the erythromycin group than the trials that compared erythromycin with other oral antibiotics.
Overall completeness and applicability of evidence
The large number of treatments evaluated (50) supports the view that there is no widely accepted standard therapy for impetigo. Most studies did not contribute clear answers about the vast choice of treatment options. Many of the studies were underpowered; this is partly due to the fact that many trials included several skin infections, impetigo being only one of them (these studies are directed at the drug rather than at the disease). In many cases, significant differences became insignificant when impetigo participants were considered after excluding participants with other sorts of infection. Another drawback of this type of study is that the age of participants is much higher than the typical age at which people contract impetigo (e.g. Blaszcyk 1998; Bucko 2002a; Bucko 2002b; Kiani 1991). The dosage of studied antibiotics may differ between studies, complicating the comparability of studies; however, the same doses were usually used (e.g. erythromycin 40 mg/kg/day). Cure rates of specific treatments can be different between studies, e.g. of fusidic acid and mupirocin (Sutton 1992; White 1989). This may be explained by the fact that investigations were done in different regions and times, and inclusion criteria differed.
Little is known about the 'natural history' of impetigo. Therefore, the paucity of placebo-controlled trials is striking, given that impetigo can be considered a minor disease. Only seven placebo-controlled studies have been conducted (Eells 1986; Gould 1984; Ishii 1977; Koning 2003; Koning 2008; Rojas 1985; Ruby 1973). The 7-day cure rates of placebo groups in these studies varied but can be considerable (0% to 42%).
The disinfectant agents, such as povidone iodine and chlorhexidine, recommended in some guidelines (Hay 1998; Resnick 2000), usually as supplementary treatment, have been inadequately studied and not compared to placebo treatment. Hydrogen peroxide cream was not significantly less effective than fusidic acid (cure rate 72% versus 82%) in a relatively large trial (Christensen 1994). We judged that blinding in this trial was inadequate.
There is a commonly accepted idea that more serious forms of impetigo (e.g. participants with extensive lesions, general illness, fever) need oral rather than topical antibiotic treatment. This principle cannot be evaluated using the data included in our review as trials that study local treatments usually exclude participants with more serious forms of impetigo.
One of our primary outcomes was relief of symptoms, such as pain, itching, and soreness, as assessed by participants (or parents). Surprisingly, only one of the studies addressed this outcome (Giordano 2006).
Resistance patterns of staphylococci - which causes impetigo - change over time. Outcomes of studies dating back more than 10 years, which form the majority of trials in this review, may not be applicable to the current prevalence of infecting agents. Also, resistance between regions and countries may vary considerably. Thus, up-to-date, local characteristics and resistance patterns of the causative bacteria should always be taken into account when choosing antibiotic treatment. In addition, health authorities and other relevant bodies may advise against prescribing certain antibiotics for impetigo, in order to restrict the development of bacterial resistance and reserve these drugs for more serious infections.
Quality of the evidence
Although the total number of randomised trials we identified was considerable, the average number of participants per study was small. In this update, the newly added studies made this average increase from 62 to 84 per study. This was partly due to studies that assessed a range of infections and randomised a large number of participants, but in which those with impetigo were only a minority. Through the years, we found an increase in the quality of the studies; the average number of items scored positively increased from less than three in the 1970s to almost five for studies published in the new millennium. This is a problem shared with many other reviews. Details of the design of the studies were often lacking in the published reports, leading to a lot of question marks in the 'Risk of bias' tables.
Potential biases in the review process
Several studies included participants with impetigo next to participants with other conditions, but they did not report results of those with impetigo separately. However, as the number of participants with impetigo was often small in these studies, we do not expect that our conclusions would be different.
Three authors on this review are authors of one included trial (Sander Koning, Lisette WA van Suijlekom-Smit, Johannes C van der Wouden; Koning 2003), Sander Koning and Johannes C van der Wouden were also involved in a second trial (Koning 2008) which was initiated by the manufacturer of the drug. These authors were not involved in the assessment of the risk of bias for both studies.
Agreements and disagreements with other studies or reviews
Topical mupirocin and fusidic acid can be considered as effective as, or more effective than, oral antibiotics, and these topical agents have fewer side-effects. This finding is in sharp contrast to the previously held view that oral treatment is superior to topical treatment (Baltimore 1985; Tack 1998). Other topical antibiotics, excluding retapamulin, were generally inferior to mupirocin, fusidic acid, and oral antibiotics. The study by Vainer is an exception: no difference was seen between tetracycline/bacitracin cream, neomycin/bacitracin cream, and fusidic acid (Vainer 1986). Fusidic acid, mupirocin, and retapamulin are the only topical antibiotics that have been compared to placebo (and shown to be more effective).
For the results of the study comparing topical fusidic acid to retapamulin (Oranje 2007), the P value computed by Review Manager (RevMan) differs from the study report (0.07 in RevMan vs 0.062 in the study report) due to different methods (94.8% vs 90.1% cure, favouring retapamulin).
None of the studies reported cases of acute (post-streptococcal) glomerulonephritis. This complication has always been an important rationale for oral antibiotic treatment. This reported absence of glomerulonephritis may reflect the reduced importance of streptococci in impetigo. It should be noted that study sizes are small and glomerulonephritis is rare.
Several of the interventions used for impetigo have also been applied in other situations where Staphylococcus aureus, the main bacterium causing impetigo, plays a role. Here we review some of these, as reported in recently published Cochrane reviews. The effect of mupirocin ointment for preventing S. aureus infections in nasal carriers was superior to that of placebo or no treatment (van Rijen 2008). Birnie 2008 assessed interventions to reduce S. aureus in the management of atopic eczema, but the review did not find clear evidence of benefit for any of these. A review of the treatment of bacteraemia due to S. aureus is under way (Cheng 2009), as is a review of antibiotics for S. aureus pneumonia in adults (Shankar 2007). Mastitis in breastfeeding women is also caused by S. aureus. A recent Cochrane review found insufficient evidence to confirm or refute the effectiveness of antibiotic therapy (Jahanfar 2009).
Acknowledgements
The authors would like to thank the following people from the editorial base for their substantial contribution to this review: Finola Delamere, Philippa Middleton, and Tina Leonard. They would also like to thank Seungsoo Sheen for his help in assessing a Korean paper, Mingming Zhang for assessing two Chinese papers, Alain Claudy for providing the outcomes for the participants with impetigo in his study, and Tetsuri Matsumura for assessing the risk of bias and extracting data from Ishii 1977.
The Cochrane Skin Group editorial base would like to thank the following people who commented on this update: our Key Editor Sue Jessop, our Statistical Editor Jo Leonardi-Bee, our Methodological Editor Philippa Middleton, Inge Axelson who was the clinical referee, and Philip Pocklington who was the consumer referee.
Appendices
Appendix 1. CENTRAL search strategy
#1(impetig* or pyoderma ):ti
#2MeSH descriptor Impetigo explode all trees in MeSH products
#3(#1 OR #2)
#4SR-SKIN in All Fields in all products
#5(#3 AND NOT #4)
Appendix 2. MEDLINE (OVID) search strategy
1. randomized controlled trial.pt.
2. controlled clinical trial.pt.
3. randomized.ab.
4. placebo.ab.
5. clinical trials as topic.sh.
6. randomly.ab.
7. trial.ti.
8. 1 or 2 or 3 or 4 or 5 or 6 or 7
9. (animals not (human and animals)).sh.
10. 8 not 9
11. exp Staphylococcal Infections/ or stapylococcal skin infections.mp.
12. impetigo.mp. or exp Impetigo/
13. exp Pyoderma/ or pyoderma.mp.
14. 11 or 13 or 12
15. 10 and 14
Appendix 3. EMBASE (OVID) search strategy
1. random$.mp.
2. factorial$.mp.
3. (crossover$ or cross-over$).mp.
4. placebo$.mp. or PLACEBO/
5. (doubl$ adj blind$).mp. [mp=title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer name]
6. (singl$ adj blind$).mp. [mp=title, abstract, subject headings, heading word, drug trade name, original title, device manufacturer, drug manufacturer name]
7. (assign$ or allocat$).mp.
8. volunteer$.mp. or VOLUNTEER/
9. Crossover Procedure/
10. Double Blind Procedure/
11. Randomized Controlled Trial/
12. Single Blind Procedure/
13. 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 12
14. impetigo.mp. or exp IMPETIGO/
15. exp PYODERMA/ or pyoderma.mp.
16. exp Staphylococcus Aureus/ or stapylococcus aureus.mp.
17. 16 or 15 or 14
18. 13 and 17
Appendix 4. LILACS search strategy
((Pt RANDOMIZED CONTROLLED TRIAL OR Pt CONTROLLED CLINICAL TRIAL OR Mh RANDOMIZED CONTROLLED TRIALS OR Mh RANDOM ALLOCATION OR Mh DOUBLE-BLIND METHOD OR Mh SINGLE-BLIND METHOD OR Pt MULTICENTER STUDY) OR ((tw ensaio or tw ensayo or tw trial) and (tw azar or tw acaso or tw placebo or tw control$ or tw aleat$ or tw random$ or (tw duplo and tw cego) or (tw doble and tw ciego) or (tw double and tw blind)) and tw clinic$)) AND NOT ((CT ANIMALS OR MH ANIMALS OR CT RABBITS OR CT MICE OR MH RATS OR MH PRIMATES OR MH DOGS OR MH RABBITS OR MH SWINE) AND NOT (CT HUMAN AND CT ANIMALS)) [Palavras] and (impetigo or pyoderma or piodermia or piodermitis or (staphyloccus aureus) or estafilococo) [Palavras]
Contributions of authors
Conceiving the review - SK, JCvdW, and LvSS
Designing the review - SK, JCvdW, LvSS, CCB, and AM
Co-ordinating the review - SK and JCvdW
Data collection for the review - SK, JCvdW, and RvdS
Developing the search strategy - JCvdW
Undertaking searches - JCvdW, SK, and RvdS
Screening search results - JCvdW, SK, and RvdS
Organising retrieval of papers - JCvdW, SK, and RvdS
Screening retrieved papers against inclusion criteria - LvSS, SK, and RvdS
Appraising quality of papers - JCvdW, AV, and RvdS
Abstracting data from papers - CCB, AM, RvdS, and JCvdW
Writing to trial authors of papers for additional information - SK, RvdS, and JCvdW
Obtaining and screening data on unpublished studies - JCvdW, SK, and RvdS
Data management for the review - SK, RvdS, and JCvdW
Entering data into RevMan - SK, JCvdW, and RvdS
Analysis of data - SK, RvdS, and JCvdW
Interpretation of data - all authors
Providing a methodological perspective - JCvdW
Providing a clinical perspective - SK and CCB
Providing a policy perspective - SK and CCB
Writing the review - SK, RvdS, and JCvdW
Providing general advice on the review - all authors
Securing funding for the review - JCvdW
Performing previous work that was the foundation of current study - LvSS, JCvdW, and SK
Declarations of interest
Three authors of this review are authors of one included trial (Sander Koning, Lisette WA van Suijlekom-Smit, Johannes C van der Wouden; Koning 2003).
Sander Koning and Johannes C van der Wouden were also involved in a second trial (Koning 2008), which was initiated by the manufacturer of the drug. As employees of Erasmus MC, Rotterdam, Johannes C van der Wouden and Sander Koning received research funding from GlaxoSmithKline for participating in a study comparing retapamulin to placebo in participants with impetigo. The funding was used to pay staff involved in field work. They were also involved in publishing the results. The study was included in the update of this review.
Differences between protocol and review
In case of studies assessing cure at more than one point in time, the protocol did not specify what time point to select for data extraction. From the start of the review, we chose the assessment that was closest to one week from the start of treatment.
For this update, the scoring of methodological quality was changed into the newly recommended 'Risk of bias' table (Higgins 2008).We also used risk ratio as recommended by the Cochrane Skin Group.