What is impetigo (school sores)?
Impetigo, commonly known as school sores, is a highly infectious superficial skin infection. It is traditionally divided into non bullous impetigo and bullous impetigo
What causes impetigo?
The infection is caused by the bacteria staphlococcus aureus (60%), streptococcus pyogenes (10%) or both (30%), which directly invade the upper layers of the skin. The infection often arises in skin that has been exposed to minor trauma such as cuts, scratches, grazes, or insect bites.
Alternatively the infection may occur in individuals with pre-existing skin conditions like eczema, where the skin is already damaged. The condition commonly affects the limbs and face, especially around the nose and mouth.
What are the symptoms?
In non bullous impetigo the infection begins as a small blister filled with fluid or pus, that is surrounded by an area of redness and swelling. The blister breaks releasing a honey coloured fluid and leaves a yellow-brown crust. There may be many of these blisters or crusts present at one time, with new ones continuing to form whilst existing ones heal.
Bullous impetigo is a rarer type of impetigo caused by staphlococcus aureus. The bacteria releases a toxin that causes larger blisters (up to 1-2cm) which burst to form erosions. These erosions may join together to form large areas of crusted skin.
Impetigo may be accompanied by itching and burning. Additionally the glands may be enlarged in the groin, armpit or neck. However, the person affected by impetigo is usually well, without any generalised symptoms.
- Children aged 2-5 years are the most frequently affected, but adults can also be infected.
- Impetigo is the most common bacterial skin condition of childhood.
- There is a greater risk of impetigo in situations of poor hygiene and poor social circumstances.
- Impetigo often occurs in late summer and early autumn.
- Impetigo may be spread from child to child by direct contact. There is usually about 4-10 days between contact and eruption of sores.
- Spread of infection often occurs at school or daycare centers.
How is impetigo diagnosed?
The diagnosis is usually made on simple inspection of the blisters/crusts. A swab can be taken from the infected skin to confirm the presence of the bacteria. This also allows doctors to find out which antibiotic will best kill the bacteria.
How is impetigo treated?
Management of impetigo is two-fold - by destroying the bacteria causing the disease with the use of antibiotics and by removing bacteria that are living on the skin.
Crusts should be removed after they are softened with a damp cloth soaked in warm salty water. Antibiotic ointment can then be directly applied to the sore. This should be done every day for a week.
At the same time, a number of things can be done to remove bacteria from the skin:
- Gently scrub skin with antiseptic soap OR take a daily bath with a small amount of Janola (chlorine) bleach added.
- Wash all towels, linen, and clothing with detergent and hot water. Keep these separate from the rest of the family while the infection is present.
- Inform school or daycare center so toys and surfaces can be sanitised.
- Bacteria living in the nose can be killed with antibiotic ointment. This may be an essential part of treatment in some individuals, as the nose tends to harbour the staphylococcus bug
Other steps that can be taken to prevent the spread of impetigo:
- Keep fingernails short and clean to prevent spread of the infection by scratching.
- Cover each sore with a plaster or gauze, and change this once a day.
- Avoid swimming and contact games.
- Keep the child home from school until the infection has cleared.
- Keep cuts an