Rationales

The recommendations in this guideline are based on the evidence identified and the experience of the committee.

Advice to reduce the spread of impetigo

Why the committee made the recommendation

Recommendation 1.1.1

The committee agreed, based on its experience, that good hygiene measures help reduce the spread of impetigo, both to other areas of the body and to other people. The committee noted that resources are available with further information (see management of impetigo in NICE's clinical knowledge summary on impetigo).

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Initial treatment

Why the committee made the recommendations

Recommendations 1.1.2 to 1.1.6

The evidence showed that impetigo was cured or improved with a placebo in some people. However, impetigo is highly infectious, and the committee agreed that treatment is important to limit the spread of infection and the worsening of symptoms, and to hasten recovery. A faster recovery is also likely to mean less time off school, nursery or work.

It was not clear in the evidence reviewed if impetigo was localised or widespread. The committee agreed that different treatment options are appropriate for impetigo based on the type and extent of the infection. It agreed that clinical judgement should be used to determine whether impetigo is localised or widespread.

Localised non-bullous impetigo

The evidence suggested that hydrogen peroxide 1% cream (a topical antiseptic) is as effective as a topical antibiotic for treating impetigo. Impetigo was cured or improved in a large proportion of people using hydrogen peroxide. The committee noted this evidence came from 1 randomised controlled trial. Based on its experience, the committee agreed that the risk of adverse effects from hydrogen peroxide at 1% concentration, such as irritation and skin bleaching, are minimal. They also agreed that the significance of this is especially low when compared with the risk of adverse effects associated with topical antibiotics, such as rapid development of antimicrobial resistance.

The committee was aware that the use of hydrogen peroxide 1% cream for impetigo is a change in practice and health professionals may not be familiar with its use. It noted that some other topical antiseptics are licensed for superficial skin infections, which may be cheaper and more widely available. However, no evidence was identified for treating impetigo with other topical antiseptics, so the committee could not make a recommendation for their use. Based on the available evidence, the committee agreed that the long-term benefits of good antimicrobial stewardship, in combination with the low risk of adverse events compared with using a topical antibiotic, outweighed the additional cost of hydrogen peroxide 1% cream.

Overall, the evidence showed that a topical antibiotic was as effective as an oral antibiotic for curing or improving impetigo. Based on the evidence and its experience, the committee agreed that topical antibiotics would cause fewer adverse effects than oral antibiotics, and that applying a topical antibiotic is usually straightforward for localised impetigo. The committee discussed its experience of antimicrobial resistance with topical antibiotics compared with oral antibiotics. It agreed that the likely increased risk of resistance with topical antibiotics applied to a localised area of impetigo for a short duration was outweighed by the increased risk of adverse events with oral antibiotics. The committee therefore agreed that if hydrogen peroxide 1% cream is unsuitable, for example, because impetigo is around the eyes, a topical antibiotic should be offered for people who are not systemically unwell or at high risk of complications.

Widespread non-bullous impetigo

Based on its experience, the committee agreed that people with widespread non-bullous impetigo should be offered a short course of either a topical or an oral antibiotic. They discussed that the choice of topical or oral use would be an individualised clinical decision, taking local antimicrobial resistance data into account alongside patient preference, practicalities of administration, possible adverse effects and previous use.

The committee discussed that effectively applying a cream may be difficult over larger skin areas. It agreed that an oral antibiotic may be a better option for some people with widespread non-bullous impetigo, despite the higher risk of adverse events, and that the decision should be based on a discussion of the person's preferences and the balance of risks and benefits. Antimicrobial resistance can develop rapidly with the use of topical antibiotics, and the committee agreed that repeated doses or extended use of the same topical antibiotic should be avoided.

Bullous impetigo or impetigo in people who are systemically unwell or at high risk of complications

The evidence on treating bullous impetigo was limited to a small study in newborn babies. From its experience, the committee discussed that the presence of bullae may mean that a topical antibiotic is unable to reach the infected area. Therefore, it agreed that an oral antibiotic is needed to target the infection adequately.

No evidence was identified for treating people who are systemically unwell or at higher risk of complications. Based on its experience of current practice, and because of the high risk of harm if topical application of antibiotic is inadequate, the committee agreed that this population should be offered an oral antibiotic. People at higher risk of complications can include, for example, people who are immunocompromised or have coexisting skin conditions.

Combination treatment

The evidence suggested that combination treatment with an oral and topical antibiotic was no more effective than a topical antibiotic alone. The committee agreed that combination treatment should be discouraged because of the increased risk of adverse events and antimicrobial resistance.

Research recommendation

The committee agreed that further research is needed to more clearly show which populations would benefit from antiseptic treatment. A research recommendation was developed to encourage more research in this area, which may contribute to future antibiotic-sparing recommendations and help reduce the risk of resistance and adverse events with antibiotics.

For more detail see the summary of the evidence on antimicrobials.

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Reassessment and further treatment

Why the committee made the recommendations

Recommendations 1.1.8 to 1.1.14

No evidence was identified for reassessing people with impetigo if initial treatment is unsuccessful. Therefore, the committee agreed on good practice points for this population based on consensus.

Based on its experience and the evidence for initial treatment, the committee agreed that a short course of a topical antibiotic should be offered for localised non-bullous impetigo if hydrogen peroxide 1% cream is ineffective. If impetigo becomes widespread after treatment, a short course of a topical or oral antibiotic should be offered, in line with the recommendation for initial treatment for widespread non-bullous impetigo. Although there is no evidence that oral antibiotics are more effective than topical antibiotics, the committee agreed that an oral antibiotic is more likely to target all areas of infection and that there is a risk of inadequate application of topical antibiotics. Based on its experience, the committee decided that an oral antibiotic should be an option if a topical antibiotic is unsuccessful. It also agreed that microbiological testing of an area of infected skin may help to guide antimicrobial prescribing.

For people with impetigo that recurs frequently, the committee agreed that a skin swab should be sent for microbiological testing to determine antimicrobial susceptibility. A nasal swab should also be considered if nasal carriage of Staphylococcus aureus is suspected. A nasal or skin (or combination) decolonisation regimen should be considered, based on clinical judgement and microbiological test results, in order to remove the bacteria causing recurrence of infection. The committee recognised that family decolonisation may be appropriate in some cases but did not make a recommendation because this decision should be based on specialist advice.

The committee agreed on good practice for antimicrobial stewardship when reviewing the results of microbiological tests. This includes changing to a narrow-spectrum antibiotic or continuing with a narrow-spectrum antibiotic that has shown resistance in microbiological tests if symptoms are already improving.

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Referral and seeking specialist advice

Why the committee made the recommendations

Recommendations 1.1.15 to 1.1.16

Based on its experience, the committee agreed that people who may have a more serious illness or condition or are immunocompromised with widespread impetigo need further assessment and treatment in hospital. Sometimes impetigo is difficult to treat (for example, bullous impetigo or impetigo that recurs frequently) and the committee agreed that referral or specialist advice should be an option.

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Choice of antimicrobial

Why the committee made the recommendation

Recommendation 1.2.1

Choice of antiseptic

The evidence suggested that hydrogen peroxide 1% cream is effective and based on its experience, the committee agreed that a short course of treatment is associated with a low risk of adverse events. There was no evidence identified for other topical antiseptics.

Choice of antibiotic

The evidence showed that fusidic acid is as effective as other topical antibiotics and is associated with fewer adverse events. Based on this evidence, current practice and its experience, the committee agreed that the first-choice topical antibiotic in adults, young people and children with non-bullous impetigo when hydrogen peroxide 1% cream is unsuitable (including when impetigo is widespread) is fusidic acid 2% (either as a cream or an ointment). Based on its experience, the committee agreed that fusidic acid resistance rates are higher than for some other antibiotics. However, the evidence showed fewer skin reactions with fusidic acid compared with mupirocin. The committee agreed that the risk of antimicrobial resistance should be considered when offering an antibiotic, but that this risk is likely to be low in people with a first episode of impetigo.

The alternative topical antibiotic in adults, young people and children with non-bullous impetigo (when a topical antiseptic is unsuitable or has been ineffective) and fusidic acid resistance is suspected or confirmed is mupirocin 2% (either as a cream or an ointment). The committee based this on its experience and knowledge of current practice, evidence that mupirocin is as effective as other topical antibiotics for treatment of impetigo and its experience that mupirocin resistance rates are low.

National antimicrobial resistance data from Public Health England's voluntary surveillance reports on Staphylococcus aureus showed resistance rates for methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infection of 13% for fusidic acid and less than 1% for mupirocin in 2018. The equivalent rates for methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection were 25% and 3%. However, the committee discussed that resistance rates in blood isolates may not be a good indicator of resistance rates in skin isolates, which can vary greatly from person to person, based on their history of antibiotic use, and between localities.

There was some evidence showing that topical ozenoxacin is more effective than placebo for treating impetigo. However, because the evidence did not compare topical ozenoxacin with another antibiotic, the committee could not make recommendations for its use. It was also noted that topical ozenoxacin is not currently available in the UK.

Based on its experience and knowledge of current practice, the committee agreed that the first-choice oral antibiotic in adults, young people and children is flucloxacillin. This is a relatively narrow-spectrum penicillin that is effective against Staphylococcus aureus and Streptococcus pyogenes. The committee recognised that some children may not be able to tolerate flucloxacillin solution or swallow capsules. For these children, the alternative oral antibiotic is suitable.

The alternative oral antibiotic in adults, young people and children with penicillin allergy or if flucloxacillin is unsuitable is clarithromycin or erythromycin (in pregnancy). The committee agreed that these antibiotics are effective against the common pathogens that cause impetigo, and the evidence indicated that macrolides are as effective as penicillins for treating impetigo.

The committee discussed that in its experience, MRSA infection in impetigo is rare and that appropriate antibiotic choice may depend on local antimicrobial resistance rates. Therefore, the committee agreed that for people with suspected or confirmed MRSA, a local microbiologist should be consulted.

Course length and dosage

There was very little evidence on dosage and course length. Therefore, the recommendations were based on committee experience of current practice and the BNF. The committee also agreed that the shortest course that is likely to be effective should be prescribed to reduce the risk of antimicrobial resistance and adverse effects. All doses are given as in the BNF. Based on its experience that lower doses are not clinically effective due to poor oral bioavailability, the committee agreed that the higher dose for flucloxacillin recommended in the BNF is appropriate for treating impetigo in adults. The committee agreed that dose ranges are appropriate for children as the appropriate dose may vary depending on the age and weight of the child.

From its experience, the committee agreed that 5 days of treatment would be sufficient for treating most people with impetigo, and this is consistent with current practice. However, the committee was aware that some people may need a longer course because of the severity or number of lesions, so agreed that this could be up to 7 days, based on clinical judgement. The committee noted current BNF advice that topical fusidic acid and mupirocin should not be used for longer than 10 days.

For more details see the summary of the evidence on choice of antibiotic.

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  • Public Health England
  • National Institute for Health and Care Excellence (NICE)