Impetigo means that bacteria has invaded and infected the area of the skin. Because it is caused by bacteria, it can be effectively treated with proper antibiotics. It usually is a yellow, crusted, oozing area of the skin, with some redness. Impetigo is contagious on skin contact, especially if there are any cuts into the skin where the bacteria can enter the skin. So it is important to avoid direct contact with other people and change all personal items (such as towels or linen) regularly while infected. Usually, the contagious period ends within two days after beginning treatment.
Impetigo can be a complication of other skin conditions. For example, once the skin has a cut from surgery or sores (e.g. from herpes), bacteria can enter those wounds. Impetigo requires prompt and immediate treatment to eradicate the bacteria and minimize its spread.