Impetigo, a highly contagious and common skin infection, typically affects infants and children. If an adult comes in contact with an infected child, they can develop Impetigo. Impetigo is caused by two bacterial infections called staphylococcus aureus or streptococcus pyogenes. The bacterial infection occurs on the outer layers of your skin, called the epidermis. It typically appears as sores on different areas of the face such as the nose and mouth. The skin condition also appears on the hands and feet.