Impetigo is a highly contagious bacterial skin infection that most commonly affects children but can occur in people of any age. It appears as red sores or blisters that can burst and form a yellowish-brown crust. The infection usually develops around the nose, mouth, or hands, but it can spread to other areas through touch or contact with contaminated items like towels or clothing.

The infection is caused by bacteria, typically Staphylococcus aureus or Streptococcus pyogenes. These bacteria can enter the skin through small cuts, insect bites, or other breaks in the surface. Warm, humid conditions and poor hygiene can increase the risk of developing impetigo, especially in crowded environments such as schools or sports settings.

There are two main types of impetigo: non-bullous and bullous. Non-bullous impetigo is the most common form and starts as small red spots that quickly form blisters and crusts. Bullous impetigo, usually caused by Staphylococcus aureus, involves larger fluid-filled blisters that may be painful and take longer to heal. Both forms are easily spread through skin contact.