Impetigo
Golden crusts around the mouth and nose in a child. Small patch: cream. Widespread or blistering: oral antibiotics. Look for scabies underneath.
A 5-year-old boy has golden, honey-coloured crusts around his nose and mouth for 4 days, spreading to his chin. He is well and afebrile. His 3-year-old sister has the same. He has itchy papules between his fingers and on his wrists, worse at night, and the whole family is scratching.
Cream or tablets, and what else is going on?
- Unwell, fever, widespread or peeling skinThink cellulitis or staphylococcal scalded skin: refer and treat systemically.
- Localised, few lesionsHydrogen peroxide 1% cream, or a topical antibiotic if unsuitable.
- Widespread, bullous or not respondingOral flucloxacillin for 5 days.
- Look for the cause underneathScabies, eczema, head lice, insect bites.
- HygieneWash crusts gently, own towels, short nails, wash hands.
- SchoolStay off until crusted over or 48 hours after starting antibiotics.
- Fever or unwell child
- Widespread blistering or skin peeling
- Facial swelling around the eye
- Dark urine, puffy face or high BP afterwards
- Newborn baby with impetigo
- Scabies underneath
- Eczema herpeticum (punched-out erosions in eczema)
- Staphylococcal scalded skin syndrome
- Herpes simplex (grouped vesicles)
- Post-streptococcal glomerulonephritis
- Cellulitis
| Localised | Hydrogen peroxide 1% cream 2–3 times daily for 5 days |
| Topical antibiotic | Fusidic acid 2% 3 times daily for 5 days if peroxide unsuitable |
| Widespread or bullous | Flucloxacillin orally for 5 days (child 25 mg/kg 4 times daily, adult 500 mg 4 times daily) |
| Penicillin allergy | Clarithromycin for 5 days |
| School exclusion | Until lesions crusted, or 48 hours after starting antibiotics |
| Scabies | Permethrin 5% cream for the whole household, repeat after 7 days |
Check every dose against a current drug reference and your hospital protocol.
On this page
What is impetigo?
A superficial skin infection, mainly with Staphylococcus aureus, sometimes Streptococcus pyogenes. Very common in young children, especially in hot, humid weather and crowded homes. Highly contagious by touch and shared towels. It often starts in skin already broken by scabies, eczema, insect bites or head lice.
Types
| Type | Look | Cause |
|---|---|---|
| Non-bullous (common) | Red patches that weep then form golden, honey-coloured crusts, usually around nose and mouth | Staph aureus, sometimes Strep |
| Bullous | Fragile blisters leaving raw areas with a thin brown crust; nappy area, trunk | Staph aureus exfoliative toxin |
Look for the cause underneath
- Scabies
- Permethrin for the whole household
- Eczema
- Emollients, steroid cream after infection treated
- Head lice
- Treat lice
- Prevent bites
- treat infection
Differential diagnosis
| Condition | Clues |
|---|---|
| Herpes simplex | Grouped vesicles, recurrent at the same spot |
| Eczema herpeticum | Punched-out erosions in eczema, unwell: urgent aciclovir |
| Scalded skin syndrome | Unwell, fever, widespread tender peeling skin |
| Fungal infection | Ring-shaped, scaly edge |
| Chickenpox | Spots in different stages, fever |
| Contact dermatitis | Itchy, matches the contact |
Treatment
- Localised, child wellHydrogen peroxide 1% cream for 5 days.
- Peroxide unsuitableFusidic acid 2% cream for 5 days (limit use to avoid resistance).
- Widespread, bullous or failing topicalOral flucloxacillin 5 days (clarithromycin if allergic).
- Unwell or peelingAdmit or refer; IV antibiotics.
Hygiene advice
- Gently wash off crusts with soap and water.
- Separate towels, flannels and pillowcases; wash them hot.
- Keep nails short; avoid scratching.
- Wash hands after touching the skin.
Complications
- Post-streptococcal glomerulonephritis: 1–3 weeks later, dark or "cola" urine, puffy face, high BP. Check urine and BP if symptoms.
- Cellulitis, lymphangitis, sepsis (rare).
- Staphylococcal scalded skin syndrome in young children.
- Scarring is rare.
Common mistakes
- Treating impetigo and missing scabies in the whole family.
- Using long courses of fusidic acid (resistance).
- Using steroid cream on untreated impetigo.
- Missing eczema herpeticum in a child with eczema.
- Not giving school exclusion advice.
Frequently asked questions
What is the treatment of impetigo?
Localised impetigo: hydrogen peroxide 1% cream (or fusidic acid if unsuitable) for 5 days. Widespread or bullous: oral flucloxacillin for 5 days.
When can a child with impetigo go back to school?
When the lesions have crusted over, or 48 hours after starting antibiotics.
Is impetigo contagious?
Yes. It spreads by touch and shared towels. Good hygiene and treatment reduce spread.
What complication follows streptococcal impetigo?
Post-streptococcal glomerulonephritis, 1–3 weeks later, with dark urine, puffy face and high BP.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. A well 5-year-old has a few honey-coloured crusts around the mouth. What is the first-line treatment?
Answer: Peroxide cream. Localised non-bullous impetigo: hydrogen peroxide 1% cream (or fusidic acid if unsuitable) for 5 days.
- Oral ciprofloxacin: Not appropriate.
- Oral steroid: Worsens infection.
- No treatment: Contagious; treat.
- IV ceftriaxone: Not needed.
2. A child with impetigo has itchy papules between the fingers and siblings who itch. What underlying problem should be treated?
Answer: Scabies. Scratching from scabies or eczema often leads to impetigo; treat the whole family with permethrin.
- Urticaria: No.
- Psoriasis: No.
- Tinea: Less likely.
- Contact dermatitis: Less likely.
3. Two weeks after impetigo, a child has dark urine and puffy eyes. What complication is this?
Answer: Glomerulonephritis. Streptococcal skin infection can cause glomerulonephritis 1–3 weeks later.
- Nephrotic syndrome: Less likely after impetigo.
- UTI: No.
- Scalded skin syndrome: Different.
- Rheumatic fever: Follows throat infection, not skin.
4. A 4-year-old has honey-coloured crusted lesions around the nose and mouth spreading to other children at nursery. He is well. What is the treatment?
Answer: Topical fusidic acid. Impetigo (S. aureus, Streptococcus pyogenes): non-bullous honey-crusted lesions or bullous (staphylococcal exfoliative toxin). Localised: topical antibiotic (fusidic acid, mupirocin) or hydrogen peroxide cream; extensive/bullous/systemically unwell: oral flucloxacillin (or erythromycin/cefalexin). Hygiene, keep off school until lesions crusted or 48 h after antibiotics. Post-streptococcal GN can follow.
- Oral prednisolone: Steroids worsen infection.
- Antifungal cream: Impetigo is not fungal.
- No treatment needed: Impetigo is contagious.
5. After a superficial skin injury, which epidermal layer regenerates the epidermis?
Answer: Stratum basale. The stratum basale contains stem cells that divide to replace keratinocytes, which mature upward through spinosum, granulosum, lucidum (thick skin) and corneum over about 4 weeks. In partial-thickness burns, re-epithelialisation comes from basal cells in surviving hair follicles and sweat glands; full-thickness burns lose these and need grafting.
- Stratum corneum: Dead keratinised cells.
- Stratum lucidum: Only in thick skin; no division.
- Stratum granulosum: Keratohyalin granules; no division.
- Papillary dermis: Dermis, not epidermis.
6. In the third month of development, cells from the neural crest migrate into the epidermis. What do these cells produce?
Answer: Melanin. Melanocytes come from the neural crest and migrate into the basal layer of the epidermis, where they make melanin and pass it to keratinocytes. Langerhans cells come from bone marrow; keratinocytes from surface ectoderm.
- Keratin: Made by keratinocytes, which come from surface ectoderm.
- Sebum: Made by sebaceous glands from the epidermis (ectoderm).
- Collagen type I: Made by dermal fibroblasts (mesoderm).
- Langerhans cell antigens: Langerhans cells come from bone marrow, not neural crest.
References and dose sources
- NICE NG153 — Impetigo: antimicrobial prescribing
- Fusidic acid (topical) dosing: Drugs.com: Fusidic acid (international) (see also our fusidic acid (topical) dose page)
- Flucloxacillin dosing: Drugs.com: Flucloxacillin (international) (see also our flucloxacillin dose page)
- Clarithromycin dosing: Drugs.com: Clarithromycin dosage (see also our clarithromycin dose page)
- Permethrin dosing: Drugs.com: Permethrin topical dosage (see also our permethrin dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.