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Written by Ada’s Medical Knowledge Team

Updated on

What is impetigo?

Impetigo, or school sores, is a bacterial infection of the skin. It is caused by Staphylococcal or Streptococcal bacteria. It is a relatively common infection, and most commonly affects school-aged children. It is easily spread by skin-to-skin contact, or via objects touched by someone with the infection. It causes itchy, painless bumps or sores which become blisters and burst, leaving a light brown crust. It may take several weeks to clear but antibiotics shorten the time taken to heal and reduce the spread of the bacteria. With appropriate treatment, most people recover well.


Impetigo occurs when bacteria which normally live on the body get into small breaks in the skin and begin to overgrow. These bacteria are normally Staphylococcal and Streptococcal bacteria, which also cause other medical conditions, such as tonsillitis, boils and wound infections. This condition can affect people of all ages, although it most commonly affects children. Impetigo is most common in the warm months of the year, and in places with poor access to health care.


Impetigo begins as a red bump. This may occur on the face, arms, legs, trunk or buttocks. These bumps may develop to a blister or an open sore, which forms a yellow-brown crust. The sores are itchy but painless.


Diagnosis is usually based on the appearance of the sores. The diagnosis can be confirmed by investigating fluid from as the sores for Staphylococcal or Streptococcal bacteria.


School sores are treated by keeping the sores clean. This can be done using low-irritant soaps and antiseptic lotions, such as lotions containing iodine, along with antibiotic creams. Sores should be kept covered if possible. If there is a widespread infection, antibiotic tablets may be needed.


People with impetigo should stay home from daycare, school or work until the sores form a crust or they have had 24hrs of antibiotic treatment. Sore should be covered when returning to school or work. Maintaining good hygiene measures, such as washing hands, bed clothes and objects used by the affected person, can help to prevent spreading the infection.

Other names for impetigo

  • School sores
  • Streptococcal impetigo

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