Impetigo is a common, contagious (spread by direct contact) skin infection. Here's how to avoid it and how to treat it

Who is at risk?
Impetigo can affect people of all ages, but most commonly occurs in children between the ages of 2 and 6. The other high risk group are people who play close contact sports such as rugby. It is more common when the weather is humid and hot.

When impetigo breaks out on previously normal skin, it is termed 'primary impetigo'. When it breaks out on skin that is already broken due to a previous skin problem such as eczema, a cold sore, or a scratch, insect bite or cut, it is termed `secondary impetigo.'

The infection is most often caused by the bacterium, Staphylococcus Aureus, which is usually harmless on the surface of normal skin, but causes problems if it gets into the skin. A second bacterium, Streptococcus Pyogenes is also found in some cases of impetigo.

How does impetigo develop?
The infection is contracted via direct contact with other people with impetigo, or from bacteria carried in the noses of symptomless nasal carriers of Staphylococcus Aureus. About 3-4 days afterwards, the skin reddens a little and small blisters develop, which burst to to leave a scabby area on the skin, with a moist golden crust on top. The skin underneath the crust can become very reddened, so if the crust has been picked off, the affected skin can just look very inflamed.

The most common site for impetigo is the skin around the nose and mouth, but neck and hands are also fairly common sites for infection. It can however break out on any area of skin, and it quite often occurs in the nappy area in babies. The area of infected skin can remain quite small, but often it spreads to nearby skin, with smaller 'satellite' patches spreading outwards from the original patch.

How is it treated?
As it is so contagious, and can spread from the original infected area, impetigo should be treated with antibiotics. Small areas can be treated with an antibiotic cream for 7-10 days. The crusts should be soaked off with warm soapy water before putting the cream on, so that the antibiotic can get into the skin. If the infection is widespread or severe, antibiotic by mouth may be given instead. This would be necessary if there is a fever or swollen glands or if the patient is poorly.

What other precautions are necessary?
Children should be kept off school or nursery until there is no more blistering or crusting. The child's nails should be kept clean and short, and picking of the scabs should be vigorously discouraged to reduce the chance of it spreading. Hand washing by the cream-applier before and after application is very important. The child should have his own facecloth, towels and pillow cases, and there should be no sharing of bathwater until the infection has cleared.