Impetigo

Disclaimer These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline.  Read the full PCH Emergency Department disclaimer.

Aim 

To guide PCH Emergency Department (ED) staff with the assessment and management of impetigo.

Background 

• Impetigo is a contagious bacterial infection of the superficial layers of the epidermis caused by Streptococcus pyogenes and Staphylococcus aureus
• Impetigo is the most common bacterial skin infection in children. Commonly called school sores.
• Aboriginal and Torres Strait Islander children have the highest rates of impetigo reported in the world, and commonly present in the first weeks of life with impetigo.

There are two general types:

• Non-bullous Impetigo (impetigo infectiosa) is most common throughout childhood from the first weeks of life. The peak occurs in primary school aged children. Some children will have impetigo around the nose and mouth or occurs on the extremities at sites of trauma, scabies, tinea, eczema or insect bites. It may be itchy but rarely painful and there are no constitutional / systemic symptoms.
• Bullous Impetigo is most commonly an infection of neonates and typically occurs on the trunk and extremities. Flaccid bullae occur which rupture easily. This condition resembles a localised form of Staphylococcal Scalded Skin Syndrome (SSSS). The child may look toxic.

Pathogens

Impetigo is initiated as a Streptococcus pyogenes infection. Staphylococcus aureus is a secondary coloniser. Both pathogens are often found together.

Complications

These are relatively uncommon but include:

• Lymphadenitis
• Scarlet fever
• Osteomyelitis
• Septic arthritis
• Pneumonia
• Sepsis including Staphylococcus aureus bacteraemia and invasive Group A Streptococcus
• Post-streptococcal glomerulonephritis - rarely and does not appear to be influenced by antibiotic treatment
• Acute Rheumatic Fever
• Skin and Soft Tissue Infection e.g. Cellulitis, Abscess

Impetigo often spreads rapidly, and the infection is generally more severe in children suffering atopic dermatitis (and other dermatological conditions).

Assessment

Examination

• Lesions typically begin with a single 2 – 4 mm honey coloured vesicle that ruptures and forms a thin crust. Pus may be visible before the 1 – 2 cm crust develops over the next 24 hours. Over days the crust thickens to protect the underlying skin as it heals. The crust causes the skin to tether, and eventually falls off, leaving a flat, dry lesion that may hypopigment / hyperpigment in skin of colour or resolve completely.
• Spread to adjacent skin can be rapid, with children often having multiple lesions.
• Look for other skin conditions e.g. eczema, scabies, head lice, tinea, molluscum contagiosum, minor trauma and insect bites as these often need treatment.

Investigations

• Cultures of the lesions are only required if initial treatment has failed. If performed, swabs should be obtained collecting pus or rolling a swab in 3 directions over the surface of the crust.
• Nasal swabs (and occasionally swabs from the axillae and perineum) are helpful in cases of recurrent impetigo to identify nasal (or other) carriage of Staphylococcus aureus.

Differential diagnoses

• Viral infections (e.g. Herpes simplex virus, Varicella zoster, Molluscum contagiosum).
• Fungal infections e.g. tinea.
• Parasitic infections (e.g. scabies, head lice).
• Eczema / atopic dermatitis.

Minor trauma and insect bites are the most common cause of impetigo.

All conditions that cause the skin to itch e.g. scabies, head lice, tinea, insect bites or eczema can become secondarily infected with Staphylococcus aureus and Streptococcus pyogenes.

Management

Treatment is always required. For limited disease (≤ 2 total body lesions), topical therapy may be used. For all other presentations, systemic antibiotics are required.

Manage any itchy skin conditions that predispose to impetigo e.g. eczema, scabies, tinea, head lice.

Further information is available in the National Healthy Skin Guideline.

Initial management

• ≤ 2 total body lesions: topical mupirocin 2% ointment 15 g (rather than cream) applied to affected areas TDS (three times a day) for 5 days.
• > 2 total body lesions: systemic antibiotics are needed.
  • Discuss with the family their preference between oral cotrimoxazole BD for 3 days or a single intramuscular dose of benzathine benzylpenicillin.
    • Consider medicine allergies and previous adverse drug reactions.
    • For antibiotic information refer to Skin and Soft Tissue Infections (Paediatric Empiric Guidelines) - ChAMP.
• Manage any associated skin conditions

Health information (for carers)

Hygiene Issues

• The Kids Research Institute Australia Skin Sores factsheet is a helpful resource for families to improve knowledge prior to discharge, and the prescribed regimen can be documented on the factsheet.
• Washing hands and body with soap and water can help prevent impetigo. Not sharing towels is also important. There is no advantage to medicated soaps.
• In recurrent cases associated with nasal and other site carriage of Staphylococcus aureus, staphylococcus decolonisation may be considered. Refer to Staphylococcus aureus Decolonisation - Paediatric

School / Day Care Exclusion

• Exclude from school / daycare until lesions are healed and crusted over and no longer weeping, or until 24 hours after commencing antibiotic (topical or systemic) treatment.
• Whilst at school, lesions on exposed areas should be covered with a waterproof dressing.

Nursing

• Complete and record a full set of observations on the Observation and Response Tool and record additional information on the Clinical Comments chart.
• Implement Standard and Contact Precautions. Refer to Standard and Transmission Based Precautions – Infection Prevention and Control Manual (internal WA Health only)

Isolation

Single-room isolation is not required for skin infections.

Bibliography

1. Epps RE. Impetigo in pediatrics. Cutis. 2004 May;73(5 Suppl):25-6
2. Koning S, Verhagen AP, van Suijlekom-Smit LW, Morris A, Butler CC, van der Wouden JC. Interventions for impetigo. Cochrane Database Syst Rev. 2012 (2):CD003261
3. Staying Healthy in Child Care – Preventing infectious diseases in child care – Sixth Edition. 2024. National Health and Medical Research Council (NHMRC) [Cited 2026, March 5] Available from: Building a Healthy Australia NHMRC website
4. eTG complete [Internet]. Melbourne: Therapeutic Guidelines Limited; May 2022. [Cited 2026, March 5]
5. The Kids Research Institute Australia. National Healthy Skin Guideline: For the Diagnosis, Treatment and Prevention of Skin Infections for Aboriginal & Torres Strait Islander Children and Communities in Australia [Internet]. 2nd ed. Perth: The Kids Research Institute Australia; 2023 [cited 2026 March 5]. Available from: https://infectiousdiseases.thekids.org.au/globalassets/media/documents/our-research/healthy-skin-arf/hsg-digital-04-12-2023.pdf
   
   

Endorsed by:	Nurse, Co-director, Surgical Services	Date:	Feb 2026
		Review date:	Feb 2029

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