A to Z: Impetigo

Impetigo is a contagious skin infection caused by bacteria.

More to Know

One of the most common skin infections among kids, impetigo usually is caused by one of two bacteria: Streptococcus pyogenes (also called group A streptococcus, which also causes strep throat) or Staphylococcus aureus. Methicillin-resistant Staphylococcus aureus (MRSA) is also becoming an important cause of impetigo.

Impetigo causes blisters or sores around the nose and mouth, neck, hands, forearms, and diaper area. The two types of impetigo are bullous impetigo (large blisters) and non-bullous impetigo (crusted):

• Non-bullous impetigo is most common: tiny blisters form and soon burst, leaving small wet patches of red skin that may weep fluid. Gradually, a honey-colored crust covers the affected area.
• Bullous impetigo is characterized by larger fluid-containing blisters that appear clear, then cloudy, and are more likely to stay intact longer on the skin without bursting.

Keep in Mind

Doctors can usually diagnose impetigo based on its appearance. Occasionally, they may need to take a sample of fluid from blisters. Impetigo is typically treated with either an antibiotic ointment or medication taken by mouth.

Good hygiene can help prevent impetigo, which often develops when there is a sore or a rash that has been scratched repeatedly (for example, poison ivy can get infected and turn into impetigo).

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.