Synopsis
Distinguish superficial impetigo from deeper ulcerative ecthyma and important blistering mimics, use hygiene and finite antimicrobial treatment proportionately, and investigate non-response or recurrence.
- Non-bullous impetigo begins with thin-roofed vesicles or pustules that become honey-coloured crusted erosions, commonly around the nose, mouth and exposed limbs.
- Bullous impetigo produces larger flaccid blisters, often on trunk or flexures, and warrants oral treatment because toxin-producing staphylococci are involved.
- Ecthyma has an adherent dark crust over a punched-out ulcer extending into dermis; swab and use systemic treatment rather than treating it as a superficial spot.
- For localised non-bullous impetigo, NICE first offers hydrogen peroxide 1% cream; a short topical antibiotic is reserved when that is unsuitable or ineffective.
- Use oral flucloxacillin for bullous disease, widespread non-bullous disease when oral treatment is selected, or systemic illness; do not combine topical and oral antibiotics routinely.
- A five-day course is standard, extended to seven days according to severity and response; an unreviewed repeat is not an acceptable substitute for sampling.
- Advise hand hygiene, short nails, avoidance of scratching, no sharing towels or face cloths, and exclusion from school or work until lesions are crusted and healed or 48 hours after antibiotics begin.
- Swab worsening, non-responsive or recurrent disease and reconsider herpes, eczema, resistance, scabies and deeper infection before changing antibiotics.
Key red flags
Systemic toxicity, rapidly spreading pain or erythema, extensive bullae, mucosal involvement, periorbital disease, immunocompromise, neonatal infection, dehydration or suspected staphylococcal scalded-skin syndrome requires urgent assessment.
Rapidly expanding warmth, swelling and pain beyond lesions, fever or physiological instability indicates cellulitis or sepsis and needs urgent care.
Diffuse tenderness, fever, superficial exfoliation and widespread positive Nikolsky sign, especially in a child, suggests staphylococcal scalded-skin syndrome.
Investigation priorities
Classify non-bullous, bullous, ecthyma or invasive disease and choose treatment route.
Management branches
A small area of superficial honey-crusted lesions occurs without bullae, systemic illness or high complication risk.
- Offer hydrogen peroxide 1% cream two or three times daily for five days and explain local irritation and eye avoidance.
- If unsuitable or ineffective, choose a five-day topical antibiotic according to NICE and local resistance, rather than combining products.
- Review spread or non-response, swab when indicated and escalate to oral treatment only when extent, depth or systemic state justifies it.