This is a common superficial skin infection which is very contagious and is seen mostly in children. It can be either blistering or non-blistering. It is most commonly caused by staphylococcal infection although streptococcus pyogenes is sometimes a cause. It is spread easily by direct contact. It is more common in warm climates with high humidity and is often associated with mild skin trauma.
The bullous form of impetigo is caused by staph aureus, usually Phage II Type 71. This causes blistering. This is more common in small children. The non-blistering or non-bullous is usually caused by staph aureus but occasionally strep pyogenes. This commonly occurs at sites of minor trauma to the skin such as insect bites, reactions, abrasions, cuts, and hand burns.
This most commonly occurs in young infants or neonates and may be associated with fever. It starts as a small blister particularly on the face, trunk or buttocks. The blister will slowly enlarge to rupture leaving shiny skin which then becomes eroded. There is often a surrounding scale. The non-bullous impetigo, which makes up the majority of infections usually starts with small reddish patches measuring about 2-4mm. They evolve to form small pustules or tiny blisters. These become easily crusted with a typical yellow or honey crust. It spreads by direct extension. It is most commonly seen on the face around the nose, mouth and also the extremities. If left untreated this may resolve itself.
The diagnosis is usually clear by examination of the skin.
The application of topical antibiotics such as mupirocin cream or ointment (Bactroban) is very effective. Fusidic acid (Fucidin) is also used. If the infection is more extensive oral antibiotics such as Cloxacillin or Cephalexin are used as well as those in the erythromycin family.
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