Mohs Surgery & Dermatology Center
Impetigo is a common infection of the top layers of the skin. It occurs most frequently in children ages 2 to 6 years. It usually starts when bacteria get into a cut, scratch, or insect bite.
Impetigo is usually caused by staphylococcus (staph) bacteria, but it also can be caused by group A streptococcus bacteria (strep). The type of strep that causes a skin infection is usually different from the type that causes strep throat.
The infection is spread by direct contact with lesions (wounds or sores) or nasal discharge from an infected person. Scratching may spread the lesions. It usually takes 1 to 3 days from the time of infection to start showing symptoms. The bacteria cannot start an infection on healthy skin. There must be small cracks or wounds for it to infect.
Symptoms start with red or pimple-like lesions surrounded by reddened skin.
These sores can be anywhere on your body, but they appear mostly on the face, arms, and legs. The sores fill with pus, then break open after a few days and form a thick crust. Itching is common.
Your physician can diagnose the infection by looking at the skin lesions.
The recommended treatment is based on the severity of the problem. Mild impetigo may respond to topical antibiotics. More severe cases may require oral antibiotics. Warm, wet washcloths applied to moist or crusted areas can help keep the lesion clean and discourage spread. These washcloths should not be used by others until after they are washed in hot, soapy water. Close contact with others should be avoided, and children should remain home from school until crusted lesions are dry. New lesions should be treated immediately with topical antibiotics to avoid further spread to other parts of the body. While the lesions of impetigo tend to heal slowly, scar formation is rare. Young children will often have recurrent episodes of impetigo.