It's a humid summer day, and the air is thick with mosquitoes. A three-year-old boy is bitten on the cheek and begins to scratch vigorously, causing the skin to itch. The wound is treated and a bandage is applied, and in principle, everything is resolved. But the next day, redness begins to appear and a honey-colored scab gradually forms. For pediatricians, the diagnosis is clear. He has impetigo, a common summer skin condition caused by bacteria in the dermis. Normally, they reside within the skin barrier, but if there is a wound or bite, they can penetrate and cause an infection. It can be localized or spread throughout the skin, either because the child has scratched other areas with dirty, infected hands, or because the germs have entered the bloodstream and spread throughout the body.