IMPETIGO CAUSES
Impetigo is caused by two types of bacteria:
1. Staphylococcus aureus
2. Streptococcus pyogenes
Both types of bacteria exist harmlessly on human skin. They cause infection when there is a cut or wound. Impetigo in adults is usually the result of injury to the skin - commonly by another skin condition, such as dermatitis (inflammation of the skin). Children are usually infected after a cut, scrape or insect bite. However, children may also become infected without any apparent skin damage.
One person can become infected by touching things that an infected person has been in contact with, such as bed linen, towels, toys, and clothing. Once infected, that person can easily pass it on to other people.
Staphylococcus aureus produces a toxin that causes impetigo to spread to nearby skin. The toxin attacks a protein that helps keep skin cells bound together. As soon as this protein is damaged, the bacteria spread rapidly.
There are two ways the infection can start:
Primary impetigo - the bacteria invade the skin through a cut, insect bite, or other lesion.
Secondary impetigo - bacteria invade the skin because another skin infection/condition has disrupted the skin barrier, such as eczema or scabies.
Symptoms do not appear until four to ten days after initial exposure to the bacteria. During those days people can pass the infection on to others, and tend to do so because they do not know they are infected.
Experts say children are more likely to become infected and show symptoms because their immune systems are not yet fully developed.
