What is impetigo?
Impetigo is a bacterial infection of the surface of the skin. In the it is the most common skin infection seen in young children.
What causes impetigo?
In the UK, impetigo is usually due to a germ known as Staphylococcus aureus; in hot climates it may be due to Streptococcus pyogenes, or to a mixture of the two. These germs pass from person to person, and impetigo can spread rapidly through families and school classes - by skin-to-skin contact or, less often, by bedding, clothing and towels. However impetigo can also arrive out of the blue, with no hint of where it came from.
The germs that cause impetigo can invade normal skin, but can also take advantage of skin that is already damaged by cuts or grazes, insect bites, head lice, scabies, cold sores, or eczema.
Impetigo is most common in children, and in warm humid weather.
Is impetigo hereditary?
No, but several members of a family often get it at the same time.
What are its symptoms?
Impetigo can be sore and itchy but does not usually make you feel ill.
What does impetigo look like?
Impetigo can crop up anywhere, but is most common on exposed areas of skin such as the face - around the nose and mouth - and on the hands. It starts as groups of thin-roofed pus-filled blisters which tend to break quickly to leave round oozing patches covered with honey-coloured or brownish crusts. The patches are small at first – half an inch or so across - but slowly get bigger. Smaller ‘satellite’ patches can come up nearby and may enlarge too. As the patches clear up, their crusts fall off and the areas heal without leaving scars.
How will impetigo be diagnosed?
Your doctor will base the diagnosis on the way the rash looks, and will check to see if it has come up on top of another skin condition, such as scabies. A swab from a crusted area may be sent to the laboratory to see which germ is causing the impetigo and which antibiotic is most likely to help. However treatment should not wait until the results are through. If you are getting recurrent episodes of impetigo your doctor may take a swab from your nose to see if the infective bacteria are harbouring there.
Can impetigo be cured?
Yes. Usually it clears quickly; but it will not do so if it is based on an unrecognised underlying skin problem such as scabies or head lice.
For information about available treatments please go to this page on the website of the British Association of Dermatologists