Impetigo: the crusty facial rash that spreads fast
Last updated September 3, 2026.
Impetigo is a highly contagious bacterial skin infection that produces golden-crusted sores, usually around the nose and mouth, and it spreads through a household or classroom in days if not contained. It is most common in children aged 2 to 6, it looks alarming, and it responds quickly to antibiotic treatment.
What does it look like?
The classic form starts as small red sores or blisters, often around the nose and mouth, which burst and leave thick, honey-colored or golden crusts. The sores are usually painless but may itch, and they spread outward and to other body sites through scratching. A less common form (bullous impetigo) produces larger fluid-filled blisters, usually on the trunk. Fever and feeling unwell are unusual in simple impetigo; if your child is systemically ill, the infection may be deeper.
How does it spread?
The bacteria (usually Staphylococcus aureus or Streptococcus pyogenes) enter through broken skin: scratches, insect bites, eczema patches, or chickenpox spots. Spread is by direct contact and by shared towels, face cloths, bedding, and toys. Children are infectious until the sores are crusted over and dry, or until 48 hours of antibiotic treatment have passed. School and nursery exclusion during this window is standard.
What actually clears it?
- Antibiotics: topical fusidic acid or mupirocin cream for small, localized patches; oral flucloxacillin or clarithromycin for widespread or bullous impetigo. Most cases clear within 7-10 days of starting treatment.
- Gentle cleaning: soak crusts with warm water or saline and gently remove them before applying cream; wash hands before and after touching the sores.
- Containment: separate towels, face cloths, and bedding; wash hands frequently; keep nails short; cover sores with loose clothing or a light dressing if possible.
- School exclusion: keep the child home until sores are crusted and dry or 48 hours into antibiotics.
- Treat the underlying itch: if eczema or insect bites triggered it, managing those prevents recurrence.
When is it an emergency?
Impetigo itself is urgent only when it goes deeper: spreading redness, swelling, warmth, and pain (cellulitis), fever, or your child becoming unwell needs same-day review. A rare but serious complication in streptococcal impetigo is post-streptococcal glomerulonephritis (kidney inflammation); dark or cola-colored urine, facial swelling, or reduced urine output after impetigo needs urgent assessment. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Is impetigo dangerous?
In most cases, no: it is a superficial skin infection that clears quickly with antibiotics and leaves no scars. The risks come when it spreads deeper (cellulitis) or when the streptococcal form triggers a rare kidney complication (post-streptococcal glomerulonephritis). The warning signs for both are clear: spreading redness and swelling with fever, or dark cola-colored urine with facial swelling. Treated promptly, impetigo is a nuisance, not a danger.
How long is my child contagious?
Until the sores are crusted over and dry, or until 48 hours of antibiotic treatment have passed, whichever comes first. Before that point, the bacteria shed from the sores onto hands, towels, bedding, and toys, and the infection spreads fast. School and nursery exclusion during the contagious window is standard. Once the sores are dry and crusted, the child can return even if the marks are still visible.
Can adults get impetigo?
Yes, though it is much more common in young children. Adults catch it from their children, through broken skin (shaving nicks, eczema, insect bites), or in close-contact sports. The treatment is the same. Adults who get recurrent impetigo should be checked for nasal carriage of Staphylococcus aureus; a decolonization protocol (nasal ointment and body wash) may be needed.
Will it leave scars?
Simple impetigo does not scar; the infection is confined to the top layer of skin. The crusts can leave temporary red or dark marks that fade over weeks to months. Scarring only occurs if the child scratches deeply enough to cause a secondary wound, or if the infection goes deeper (ecthyma, the ulcerated form of impetigo). Keeping nails short and the itch controlled prevents this.
Why does my child keep getting impetigo?
Recurrent impetigo usually means one of three things: an untreated underlying skin condition (eczema is the most common: broken, itchy skin is the entry point), nasal carriage of Staphylococcus aureus in the child or a family member, or incomplete treatment courses. Addressing the eczema with regular emollients, checking for nasal carriage, and completing every antibiotic course usually stops the cycle.
Can I treat impetigo without antibiotics?
Very small, localized patches (one or two sores, caught early) are sometimes managed with antiseptic cream alone, but this is a judgment call for a pharmacist or GP, not a DIY decision. Established or spreading impetigo needs antibiotics; delaying them risks deeper infection and spreads the contagion to siblings and classmates. Over-the-counter antiseptics are not a substitute for assessment.