What is the main cause of impetigo?

Impetigo is primarily caused by a bacterial infection, most commonly Staphylococcus aureus and, less frequently, Streptococcus pyogenes (group A strep). These bacteria are naturally present on the skin or in the nose of many healthy individuals, but they become problematic when they enter the body through minor breaks in the skin. These breaks can result from cuts, insect bites, eczema, scratches, or even excessive rubbing.

In real-world clinical observations, impetigo tends to develop more frequently in environments where skin-to-skin contact is common, such as schools, daycare centers, and sports settings. Warm, humid weather also increases the likelihood of outbreaks, as bacteria thrive in such conditions. Children are particularly susceptible because their skin barrier is still developing, and they are more prone to minor injuries and close contact.

Another contributing factor is poor skin integrity rather than poor hygiene alone. For example, conditions like eczema weaken the skin’s protective barrier, making it easier for bacteria to invade. Additionally, nasal carriage of Staphylococcus bacteria can lead to repeated infections if not addressed.

From a prevention standpoint, maintaining skin health and hygiene, promptly cleaning wounds, and avoiding sharing personal items like towels can significantly reduce the risk. Understanding that impetigo is not caused by a single factor but rather a combination of bacterial exposure and skin vulnerability is key to both prevention and effective management.