In adults, it may follow other skin disorders. Impetigo may follow a recent upper respiratory infection such as a cold or other viral infection. The skin normally has many types of bacteria on it, but intact skin is an effective barrier that keeps bacteria from entering and growing within the body. When there is a break in the skin, bacteria can enter the body and grow there, causing inflammation and infection. Impetigo may occur on skin where there is no visible break.
Impetigo begins as an itchy , red sore that blisters and then oozes.
It tends to grow and spread. Impetigo is contagious. The infection is carried in the fluid that oozes from the blisters. Impetigo may rarely form deeper skin ulcers . Impetigo is highly contagious, so avoid skin contact with drainage from impetigo lesions.