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Impetigo is an infectious skin condition, usually caused by the bacteria Staphylococcus Aureus, and less commonly by Streptococcus pyogenes. 

It is highly infectious, and outbreaks often occurs in schools and within families. It causes pustules and a yellow / golden coloured crust, and is also sometimes referred to as “golden staph” or “school sores”.

It typically requires a skin defect to cause in infection – but this can something as minor as a scratch or abrasion, but it also means that it can cause secondary infections of other skin problems – such as eczema or herpes simplex.

Treatment is with topical antibiotics (in simple cases), or oral antibiotics in more complex cases.


The presentation can be divided into two types:

  • Bullous impetigo
    • Causes pustules and blisters
    • Always due to staphylococcus
    • Blisters due to toxins produced by the staphylococcus
    • Blisters are not often painful, but may be irritating
    • Blisters often leave a brown crust when they burst
Bullous Impetigo
Bullous Impetigo. mage from Dermnet. Used in accordance with Creative Commons Attribution-NonCommercial-NoDerivs 3.0 (New Zealand) license.
  • Non-bullous impetigo
    • Can be caused by staphylococcus aureus or streptococcus pyogenes
    • Not usually painful
    • May be itchy or irritating
Non-bullous impetigo
Non-bullous impetigo. mage from Dermnet. Used in accordance with Creative Commons Attribution-NonCommercial-NoDerivs 3.0 (New Zealand) license.


Medical management

  • Topical antibiotics – e.g. mupirocin cream TDS for 7/7
  • In severe or widespread infections – PO flucloxacillin 500mg QID (adults) or 12.5mg/Kg, max 250mg in children

Other factors

  • Lesions should be covered to reduce the risk of transmission
  • If lesions can’t be easily completely covered, then children should be off school until the lesions have dried, and adults should consider being off work
  • It is recommended to use antiseptics to clean the wounds – e.g. iodine based solution
  • Avoid sharing towels and clothes
  • Frequent and diligent hand hygiene but the sufferer and their family until the lesions have resolved
  • Avoid scratching or picking at lesions – the infection can easily be transferred from one site to another
  • Be wary of nose-picking – a proportion of the population carry staphylococcus in the nose indefinitely, and this can be the source of infections
  • Consider underlying factors affecting immune function in those with recurrent infection


Staphylococcus infections – whatever the source –  are associated with other diseases



  • Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
  • Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
  • Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy
  • Dermnet - Impetigo

Read more about our sources

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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) FRACGP currently works as a GP and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University, and is studying for a Masters of Sports Medicine at the University of Queensland. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

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