Impetigo is a skin infection caused by staphylococcus or streptococcus bacteria. It is also known as school sores because it commonly affects school-aged children. Impetigo is more common during the warmer months.
Staphylococcus or streptococcus bacteria can live harmlessly on and inside various areas of the body, such as the skin surface and nose. However, cuts and abrasions or eczema may allow the bacteria to cause infection in deeper skin tissues. Healthy, intact skin can sometimes develop impetigo too. The condition is characterised by collections of small, crusting blisters that usually form on the face or limbs.
Impetigo looks unsightly, but it isn’t dangerous and doesn’t cause any lasting damage to the skin. However, it is highly contagious. A child with impetigo should be kept home from school or day care until appropriate treatment has begun.
The sores on exposed areas are covered with a waterproof occlusive (no holes) dressing. Occasionally a crepe bandage may be needed to hold the dressing in place or help prevent younger children from scratching the sores.
Incubation period of impetigo
The incubation period is the time between being exposed to the bacteria and the development of signs and symptoms. The incubation period is usually one to three days for streptococcal infections and four to 10 days for staphylococcal infections.
Common symptoms of impetigo
Common symptoms of impetigo include:
- the skin itches and reddens
- a collection of blisters forms, commonly around the nose and mouth
- the blisters pop and weep a yellow, sticky fluid
- the area develops a raised and wet-looking crust
- the scab dries and falls off
- the skin completely heals after a few days.
Symptoms of severe impetigo infection
If large areas of the skin are affected, symptoms may also include:
- swollen lymph glands
- general feeling of unwellness (malaise).
Diagnosis of impetigo
Impetigo may be diagnosed by an experienced clinician on the basis of the appearance of the infection. It may also be diagnosed by taking a swab of the blisters or crust and checking for the presence of bacteria.
Treatment of impetigo
Impetigo can be treated with prescription antibiotic ointments or creams, which need to be reapplied until the sores have completely healed. Antibiotic syrups or tablets may also be prescribed. It is important to complete any course of antibiotics you are prescribed. If left untreated, impetigo can lead to skin abscesses.
Care of the impetigo infection at home
Suggestions for home care include:
- Wash the sores (lesions) with an antibacterial or antiseptic soap every eight to 12 hours, soaking off visible crust.
- After each wash, pat the lesions dry. Use a clean towel each time.
- Apply a waterproof occlusive dressing (completely cover and seal the area where possible) to stop further spread of the infection. Use a crepe bandage to hold the dressing in place or help prevent younger children from scratching the sores.
- See your doctor if the sores spread and get worse despite treatment, or if the child becomes unwell with fever.
- Change the child’s linen (towels, sheets, face washer, sleep wear) daily while the infection is present.
Avoid spreading impetigo
Impetigo blisters and crusts are filled with bacteria. This makes the condition highly contagious, particularly when the site is weeping. The skin is usually itchy, so the child scratches and spreads the infection from under their fingernails to other areas of the body or to another person. Infection can also be spread by handling contaminated clothing or articles.
Suggestions to reduce the risk of transmission to other family members include:
- Encourage everyone to wash their hands with soap frequently, and dry completely.
- A child with impetigo should be kept home from school or day care until appropriate treatment has begun and the sores on exposed areas are covered with a waterproof occlusive dressing.
- Cut your child’s fingernails short and encourage them not to scratch scabs or pick their nose.
- Avoid scratching or touching the sores to prevent spread to other areas of the body. Use a crepe bandage if necessary.
- Keep affected areas of skin clean and covered to minimise the chance of spreading the infection.
- Always wash your hands with soap before and after touching sores or scabs.
- Encourage children to use their own towel and face cloth. No sharing.
- Wash the child’s linen, towels and clothes in hot water. Wash all household linen in hot water while the infection is present.
- Dispose of used dressings promptly and thoroughly. Wash and dry hands after the dressings have been disposed of into a plastic bag and place bag into household waste.
Impetigo is dangerous for newborns
Keep the infected person well away from young babies. Impetigo is a serious condition for newborns because the newborn’s inexperienced immune system may not keep the infection in check. Without prompt treatment, a severe case of impetigo may threaten a baby’s life.
Where to get help
This page has been produced in consultation with and approved by:
Department of Health and Human Services - RHP&R - Health Protection - Communicable Disease Prevention and Control Unit
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