Causes of impetigo
In the UK, impetigo is most often caused by a type of bacteria called staphylococcus aureus. It can also be caused by the streptococcus pyogenes bacteria, usually in warmer climates.
Primary and secondary infection
An impetigo infection can occur when the bacteria invades otherwise healthy skin through a cut, insect bite or other injury. This is known as primary impetigo.
An infection can also occur when the bacteria invades the skin as a result of the skin barrier being disrupted by another underlying skin condition, such as head lice, scabies or eczema. This is known as secondary impetigo.
An impetigo infection can spread to other people through close physical contact, or by sharing towels or flannels. As the condition does not cause any symptoms until four to 10 days after initial exposure to the bacteria, it is often easily spread to others unintentionally.
Impetigo is thought to be more common in children because their immune system has not yet fully developed, making them more vulnerable to infections such as impetigo.