3. Crusting
Crusting usually occurs once the blister or sore on the skin break open and the liquid starts to ooze out. The liquid inside the blisters pushes on the skin until the blister or lesion breaks open. The fluid slowly leaks out of the skin and can dry to it and form a crust. Sometimes the crust dries directly over the lesion or blisters it came from, and sometimes it runs or dribbles to other areas.
Once the liquid dries, it sticks to the skin. It is often yellow or brown in color. If the lesions are picked or scratched and bleeding, the blood can mix with the fluid inside the blisters, and the crusting may be red. Crusting can also appear as scabs. It can be removed with alcohol or warm water. The fluid that dries to the skin and creates the crust can contain the bacteria that causes impetigo and could cause the infection to spread to other people or other parts of the body.