Impetigo: symptoms, treatment and how long it spreads

In short

• Impetigo is a mild bacterial skin infection, caused by group A strep, Staphylococcus aureus, or both. It is most common in children aged 2 to 5.
• Red, itchy sores break open, ooze clear fluid or pus, then form a yellow, honey-colored crust. They usually heal without scarring.
• It spreads by skin-to-skin contact and by touching towels, bedding or other items an infected person has used.
• Clinicians usually diagnose it by looking at the sores. A topical antibiotic treats a few sores; oral antibiotics are used for more widespread infection.
• Cover the sores, wash your hands often and do not scratch. See a clinician for any suspected impetigo, and sooner for babies, a weak immune system or sores that worsen.

What impetigo is

Impetigo is a skin infection caused by bacteria, usually Staphylococcus aureus and sometimes group A Streptococcus. It sits in the top layers of the skin and can show up anywhere on the body. It starts most easily where the skin is already broken, such as a cut, scrape, insect bite, patch of eczema or scabies.

It is very common in children, especially between ages 2 and 5. It also spreads in crowded places such as daycare, schools and shelters, and in hot, humid weather. Athletes in close-contact sports such as wrestling can get it as well.

Symptoms and what it looks like

• Red sores or blisters that may be harder to see on brown and Black skin.
• The sores burst and ooze clear fluid or pus for a few days.
• A yellow or golden-brown crust forms, which the NHS compares to cornflakes stuck to the skin.
• Usual places: around the nose and mouth, and on the hands, arms and legs.
• Itching, and sometimes pain.

A second form, bullous impetigo, makes larger fluid-filled blisters that leave a scaly rim around a scab. Sores often appear about 10 days after exposure to the bacteria.

Many skin problems look alike, including cellulitis, which is more serious, so a pharmacist or clinician should confirm it.

How it spreads and how long it stays contagious

Impetigo travels through skin contact and by sharing towels, bedding, clothing, toys or sports equipment. It often passes between members of one household. Scratching can carry it to other parts of your own body.

Untreated, the NHS says it can stay contagious for 7 to 21 days, usually until all the patches have dried and crusted over. Starting a prescribed antibiotic shortens that: the NHS says contagiousness ends 48 hours after treatment begins.

Poor hygiene, including inadequate handwashing, is listed by the CDC as one of several risk factors, alongside skin breaks, crowding and warm climates.

What to do at home

1. Get it checked first.Call your clinic before you go in, because impetigo spreads easily. A clinician can rule out a more serious infection.
2. Wash gently.Wash the sores with soap and water and dry them thoroughly. Wash your hands often, especially before and after applying any cream.
3. Do not scratch or pick.Picking at sores or crusts can spread them and cause scarring. Keep nails short.
4. Cover the sores.Covering sores on exposed skin lets most people return to work, school or daycare once antibiotic treatment has started.
5. Keep items separate.Do not share towels, bedding or flannels, and wash them hot. Wash children's toys with detergent and warm water.
6. Finish the course.Use the prescribed treatment exactly as directed, even if the skin looks better.

When to see a doctor

• You think you or your child has impetigo: it needs a prescription treatment.
• The patient is a baby, particularly under 12 months.
• Sores are on the breast while you are breastfeeding.
• You have a weakened immune system or a condition such as diabetes or eczema.
• The sores get worse during treatment, spread quickly, or return within a year.
• A fever or a sudden change in how a child feels comes with the sores.

Start with your primary care provider or your child's pediatrician; a dermatologist can see recurring cases. Untreated, new sores can keep forming for weeks and the infection can go deeper into the skin. Very rarely, strep impetigo is followed by a kidney problem or rheumatic fever.

Red flags, call 911 now: swelling of the lips, mouth, tongue or throat; fast or difficult breathing; fainting, confusion or being hard to wake; or fever with hot, painful, red skin that is spreading fast and a very unwell child or adult.

How impetigo is diagnosed

A healthcare provider usually diagnoses impetigo by examining the sores, and lab tests are normally not needed. A swab may be taken from the skin or nose if it keeps coming back.

Treatment in general terms

In the US, clinicians prescribe antibiotics: a topical ointment when only a few sores are present, and oral antibiotics for more widespread infection. Impetigo may clear on its own within a few weeks, but treatment is recommended because it shortens the illness, lowers the chance of passing it on and keeps it from going deeper.

In the UK, the NHS also lists hydrogen peroxide cream as an option for a limited patch. Babies and people with a weakened immune system may need antibiotic tablets. For frequent infections a clinician may swab the skin and nose and prescribe an antiseptic body wash, a nasal ointment, or both. All of these are used only as prescribed by a doctor.

Preventing it

Clean cuts, scratches and insect bites with warm water and soap, and treat skin conditions such as eczema and scabies. Avoid the gym and contact sports while you are contagious.

Questions and answers

Sources

1. CDC — About Impetigo
2. NHS — Impetigo
3. American Academy of Dermatology — Impetigo: Overview
4. MedlinePlus — Impetigo

Sources checked on 28 October 2026.