Information on prognosis

• Complications with impetigo, such as streptococcal-mediated glomerulonephritis, are very rare. However, visibly unpleasant lesions, especially on the face, may cause considerable distress for children and parents, so they should be reassured about the temporary nature of the infection [Watkins, 2005].

Advice on hygiene

• CKS found no controlled trials that investigated the effectiveness of hygiene practices in stopping the spread of infection or improving healing rates. However, the non-bullous form of impetigo is highly contagious, and these are generally accepted by experts as being appropriate measures [HPA, 1999; Nursing Times, 2004; Watkins, 2005; DTB, 2007].

Absenteeism from school or nursery

• This recommendation is based on advice from the Health Protection Agency [HPA, 2010].
• After consultation with expert reviewers, CKS infers that the term 'crusting' in this context refers to the scabs that form during the healing process (eschar) rather than the initial gold-crusted plaques typically seen at presentation.
• Scab formation, indicating healing, usually occurs within 2 days of starting antibiotic treatment.
• It is reasonable to extrapolate this advice to adults.

Treatment failure

• Most controlled trials have shown positive results from topical and oral antibiotics after 1 week [George and Rubin, 2003; Koning et al, 2003]. If the condition is not improving after this time, or is deteriorating, it is reasonable to extend treatment, while waiting for bacterial sensitivity data.

Passive treatment

• Passive treatment (hygiene measures alone) is not recommended, even for small, localized lesions. Although placebo-controlled trials have shown that untreated impetigo usually resolves in about 2–3 weeks [Koning et al, 2003], topical treatment is effective and has few adverse effects. In addition, untreated impetigo is highly contagious and there is a risk it may become generalized.

Topical treatment

• There is good evidence from several placebo-controlled and comparative randomized controlled trials (RCTs) that topical antibiotics are effective in the treatment of localized non-bullous impetigo [George and Rubin, 2003; Koning et al, 2003].
• Fusidic acid is recommended first-line. It is effective against Staphylococcus aureus and Streptococcus pyogenes and is licensed for the treatment of impetigo [ABPI Medicines Compendium, 2001]. It has been shown in comparative RCTs to be as effective as mupirocin and retapamulin.
• Mupirocin should be reserved for the treatment of impetigo known to be caused by meticillin-resistant Staphylococcus aureus (MRSA) because of concerns over bacterial resistance. This is in line with recommendations from the Health Protection Agency [HPA and Association of Medical Microbiologists, 2008] and the British National Formulary [BNF 56, 2008].
• Retapamulin is a newer topical antibiotic that has been shown, in a comparative RCT, to be equivalent in efficacy to fusidic acid [Oranje et al, 2007]. However, it is a black triangle drug (undergoing post-marketing surveillance), and is likely to be more expensive than fusidic acid without offering additional clinical benefit. On this basis, some experts recommend it should be reserved as a second-line treatment [DTB, 2008].
• Topical antiseptics are not recommended for the treatment of impetigo, although some specialists advocate the use of hydrogen peroxide cream in some instances. There is limited evidence from a meta-analysis of two RCTs that topical antiseptics are not as effective as topical antibiotics. They can also cause skin reactions, and antiseptics that have an alcoholic base can exacerbate dry and fissured skin [Watkins, 2005].
• Removing crusts: there is insufficient evidence from controlled trials to show whether removing the crust from lesions before application of a topical antibiotic improves their efficacy [DTB, 2008]. However, it is believed by some experts that removal of the crust will allow the antibiotic to come into direct contact with the pathogens rather than being wasted on inert, dry, exfoliating skin [Watkins, 2005]. Removal of scabs formed during the healing process is not recommended as it is likely to cause pain, bleeding, and scarring.

Oral antibiotics

• The evidence to support the use of oral antibiotics to treat impetigo is limited due to a lack of adequate placebo-controlled trials, although for localized impetigo, comparative RCTs have shown they are probably not as effective as topical antibiotics [George and Rubin, 2003; Koning et al, 2003]. However, for more extensive impetigo, or for impetigo causing systemic symptoms, oral antibiotics are the most practical option. There is little evidence on the treatment of bullous impetigo, but oral antibiotics are thought to be a reasonable option [DTB, 2007].
• Flucloxacillin is recommended as first-line treatment for extensive impetigo [HPA and Association of Medical Microbiologists, 2008]. Although there is a lack of evidence from RCTs to prove the efficacy of flucloxacillin, it is known to be effective against Gram-positive organisms, including beta-lactamase producing Staphylococcus aureus [ABPI Medicines Compendium, 2008a], and it demonstrates suitable pharmacokinetics, with good diffusion into skin and soft tissues [Finch et al, 2003].
• Erythromycin is a macrolide antibiotic with a broad spectrum of activity, including most staphylococcal and streptococcal species [Finch et al, 2003]. It has been studied relatively extensively in comparative RCTs, and been found to be superior to penicillin, and equivalent to most other antibiotics [Koning et al, 2003].
• Clarithromycin is recommended as an alternative macrolide to erythromycin. It is generally considered to cause less adverse effects than erythromycin [DTB, 1991] and although this advantage is mainly theoretical, there are some limited data from RCTs to corroborate this [Aronson, 2006]. In addition, it only requires twice-daily dosing, an important consideration for children of school age.

Follow-up

• Most controlled trials have shown positive results from topical and oral antibiotics after 1 week [George and Rubin, 2003; Koning et al, 2003] making routine follow-up unnecessary.

CKS found no evidence to guide practice on what to do if initial treatment is not effective; therefore, recommendations are pragmatic.

Treatment failure

• Most controlled trials have shown positive results from topical and oral antibiotics after 1 week [George and Rubin, 2003; Koning et al, 2003]. If the condition is not improving after this time, or is deteriorating, it is reasonable to extend treatment, while waiting for bacterial sensitivity data.
• Although topical fusidic acid is still regarded as the first-line choice by most specialists, there is increasing evidence from observational studies to suggest that bacterial resistance to it is a growing problem [Ravenscroft et al, 2000; Osterlund et al, 2002; Tveten et al, 2002; O'Neill et al, 2004]. Therefore, if treatment failure occurs with fusidic acid, an alternative such as topical retapamulin should be considered, provided infection has not become widespread.
• Switching from flucloxacillin to a different oral antibiotic (for example erythromycin or clarithromycin) is not recommended as this is unlikely to be of benefit. In this situation there is the possibility that the infection is caused by meticillin-resistant Staphylococcus aureus (MRSA) and swabs are necessary to confirm or exclude this.

Retapamulin

• Expert opinion from a narrative review recommended that retapamulin is a suitable second-line treatment for people who have not responded to topical fusidic acid [DTB, 2008].
• There is evidence from a randomized controlled trial that retapamulin is as effective as fusidic acid in the treatment of impetigo [Oranje et al, 2007].
• In contrast to fusidic acid, retapamulin has a relatively broad spectrum of activity. It acts by a different mechanism to other topical antibiotics, and development of bacterial resistance is slow (and, as it is not used systemically, it is of less concern) [Yang and Keam, 2008]. On this basis, retapamulin is a reasonable second-line choice, providing the impetigo has not spread extensively.
• It should be noted that the use of retapamulin for longer than 5 days is off licence [ABPI Medicines Compendium, 2008b], and use of topical antibiotics for longer than 2 weeks should be discouraged because of the risk of contact sensitization and development of antibiotic resistance [Yang and Keam, 2008].

Nasal staphylococcal carriage

• The recommendation for the detection and subsequent management of nasal staphylococcal carriage is based on expert opinion from CKS reviewers. Studies have shown that nasal carriage of S. aureus increases the risk of developing staphylococcal skin infections such as boils and cellulitis [Ladhani and Garbash, 2005], and it is not unreasonable to suppose there is a similar mechanism occurring with recurrent impetigo.

CKS found no evidence to guide management on when it is appropriate to refer a person with impetigo. Therefore these are pragmatic recommendations and reflect the usually benign nature of the infection.