🧭 When to suspect

Impetigo is a highly contagious superficial bacterial skin infection, most common in children aged 2 to 5 years but seen at any age. It is caused by Staphylococcus aureus, Streptococcus pyogenes, or both, and typically follows a breach in the skin barrier – a graze, insect bite, cold sore, or underlying eczema.

Suspect it in a patient with discrete lesions around the nose and mouth that begin as thin-walled vesicles or pustules and rupture to leave the characteristic golden, honey-coloured crusts. The less common bullous form presents with flaccid, fluid-filled blisters and is more often seen in neonates and infants.

The two clinical priorities in primary care are to match treatment to the extent and type of disease – supporting antibiotic stewardship – and to recognise the minority who are systemically unwell or developing complications.

Feature	Non-bullous impetigo (~70%)	Bullous impetigo (~30%)
Organism	S. aureus and/or S. pyogenes	S. aureus (exfoliative toxin-mediated)
Lesion	Vesicles/pustules rupturing to golden, honey-coloured crusts ("stuck-on cornflakes")	Flaccid bullae over 1 cm that rupture, leaving a thin brown crust with a peripheral collarette of scale
Typical site	Face – around the nose and mouth; also limbs	Trunk, flexures and nappy area; can be more widespread
Who	Any age; most common in young children	More common in neonates and infants

🧠 Clinical pearl

Bullous impetigo is driven by staphylococcal exfoliative toxins acting locally. In a neonate or infant, when those toxins spread systemically the picture shifts to staphylococcal scalded skin syndrome (SSSS) – widespread tender erythema with superficial peeling and a positive Nikolsky sign. This is a different, more serious entity needing urgent admission, not a topical cream.

Source: NICE NG153

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