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Impetigo

John Montgomery5 min read

Impetigo

Impetigo is a superficial skin infection caused by Staphylococcus aureus or streptococci. It shows as sores, honey-coloured crusts or blisters, often on the face (NHS). When it develops on top of eczema, the eczema is called impetiginised, the classic bacterial form of Infected Eczema. It can look like Eczema Herpeticum and can complicate it, so swabs may be needed (DermNet). The NHS describes red sores or blisters that burst and leave golden-brown crusts that “look a bit like cornflakes stuck to your skin”, mostly around the nose, mouth and hands. A variant where yellow fluid oozes from larger blisters is bullous impetigo. Impetigo “usually infects skin that’s already damaged”, so scratched toddler eczema is an easy entry point, and the NHS lists treating eczema as a way to prevent it.

Staphylococcus aureus [causes] Impetigo Atopic Dermatitis [worsens] Impetigo Impetigo [part-of] Infected Eczema Impetigo [relates] Eczema Herpeticum

Contagiousness and nursery exclusion. Impetigo spreads by skin-to-skin contact and via towels, bedding and toys (NHS 2024). The NHS says it stops being contagious 48 hours after starting hydrogen peroxide cream or antibiotics; untreated, it takes 7–21 days, usually when all patches have dried and crusted. Children should stay off nursery until no longer contagious. Families should wash flannels, towels and bedding hot, wash toys, and stop the child touching or scratching the crusts. UKHSA’s exclusion table says to stay away “until all blisters have formed scabs or 2 days after starting antibiotics” and does not mention antiseptic cream.

Conflict: [NHS Impetigo, 2024-06] says impetigo stops being contagious 48 hours after starting hydrogen peroxide cream or antibiotics. [UKHSA exclusion periods, accessed 2026-10] sets the nursery return point at all blisters scabbed or 2 days after starting antibiotics, with no mention of antiseptic cream. A toddler treated only with Hydrogen Peroxide Cream may be readmitted at 48 h under NHS advice but not under a strict reading of UKHSA. Unresolved — add to open_questions.

Impetigo [relates] Hydrogen Peroxide Cream Hydrogen Peroxide Cream [prevents] Impetigo

Treatment under NICE NG153. NICE NG153 (2020) puts an antiseptic first. For localised non-bullous impetigo in a child who is not systemically unwell, prescribers should consider Hydrogen Peroxide Cream 1%, applied two or three times a day for 5 days. NICE found no evidence for other topical antiseptics. If peroxide is unsuitable (for example near the eyes) or fails, the first-choice topical antibiotic is Fusidic Acid 2% three times daily for 5 days, with Mupirocin if fusidic acid resistance is suspected. Widespread impetigo can be treated with a topical or oral antibiotic. Bullous impetigo, or impetigo in a child who is unwell or at high risk, gets oral Flucloxacillin (ages 2–9: 125–250 mg four times daily for 5 days), or Clarithromycin if the child is penicillin-allergic. NICE says not to combine topical and oral antibiotics, and warns that resistance “can develop rapidly with extended or repeated use” of topical antibiotics. In the NHS, a pharmacist can treat impetigo in children aged 12 months and over; babies 11 months and under should see a GP.

NICE NG153 [regulates] Impetigo Hydrogen Peroxide Cream [treats] Impetigo Fusidic Acid [treats] Impetigo Mupirocin [treats] Impetigo Flucloxacillin [treats] Impetigo Clarithromycin [treats] Impetigo

Impetigo on eczema: which guideline? Toddlers with impetiginised eczema fall between two NICE documents. NICE NG153 covers impetigo and makes hydrogen peroxide first line. NICE NG190 covers secondary bacterial infection of eczema and advises no routine antibiotic in a well child, with Fusidic Acid for 5–7 days if one is needed. NG190 does not mention hydrogen peroxide. On eczematous skin, the cream’s suitability (stinging on broken skin) has not been studied in toddlers. Frequent use of fusidic acid on eczema selects for resistant staph: in UK children with AD, fusidic acid resistance was about 2.5 times more common than in healthy children (Harkins, BJD 2018). Recurrent impetigo calls for skin and nasal swabs and possible decolonisation (NG153; NHS).

NICE NG190 [regulates] Infected Eczema NICE NG153 [relates] NICE NG190 Fusidic Acid [relates] Staphylococcus aureus

When to worry. NG153 says to reassess if impetigo worsens or doesn’t respond, considering other diagnoses “such as herpes simplex” and signs of cellulitis. In a toddler with eczema, rapidly spreading painful punched-out sores, fever or lethargy suggest Eczema Herpeticum, which needs same-day Aciclovir rather than antibiotics (NICE QS44). NG153 advises referring babies under 1 with bullous impetigo, and immunocompromised children with widespread infection, to hospital or specialists.

Impetigo [relates] Herpes Simplex Virus Eczema Herpeticum [contradicts] Impetigo

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