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Impetigo

Impetigo, one of the most common skin infections among kids, usually produces blisters or sores on the face, neck, hands, and diaper area.

This contagious superficial skin infection is generally caused by one of two bacteria: Staphylococcus aureus or Streptococcus pyogenes (also called group A streptococcus, which also causes strep throat). Methicillin-resistant Staphylococcus aureus (MRSA) is also becoming an important cause of impetigo.

Impetigo usually affects preschool and school-age children. A child may be more likely to develop impetigo if the skin has already been irritated by other skin problems, such as eczema, poison ivy, insect bites, and cuts or scrapes.

Routinely washing the face and hands 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).

Doctors can usually diagnose impetigo based on the appearance of the rash. 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.

Signs and Symptoms

Impetigo may affect skin anywhere on the body but commonly occurs around the nose and mouth, hands, and forearms, and in young children, the diaper area.

impetigo illustration

The two types of impetigo are non-bullous (crusted) and bullous (large blisters):

  • Non-bullous or crusted impetigo is most common. It's usually caused by S. aureus but also can be due to infection with S. pyogenes. Non-bullous begins as tiny blisters that eventually burst and leave small wet patches of red skin that may weep fluid. Gradually, a yellowish-brown or tan crust covers the affected area, making it look like it has been coated with honey or brown sugar.
  • Bullous impetigo is nearly always caused by S. aureus, which releases toxins that trigger the formation of larger fluid-containing blisters that appear clear, then cloudy. These blisters are more likely to stay longer on the skin without bursting.

Contagiousness

Impetigo is contagious. It can spread to anyone who comes into contact with infected skin or other items (such as clothing, towels, and bed linens) that have been touched by infected skin. And because impetigo may itch, kids can spread the infection by scratching it and then touching other parts of their body.

Treatment

When it just affects a small area of the skin (and especially if it's the non-bullous form), impetigo usually is treated with antibiotic ointment. But if the infection has spread to other areas of the body or the ointment isn't working, the doctor may prescribe an antibiotic pill or liquid to be taken for 7-10 days.

Once antibiotic treatment begins, healing should start within a few days. It's important to make sure that your child takes the medication as prescribed. Otherwise, a deeper and more serious skin infection could develop.

While the infection is healing, gently wash the areas of infected skin with clean gauze and antiseptic soap every day. Soak any areas of crusted skin with warm soapy water to help remove the layers of crust (it is not necessary to completely remove all of it).

To keep your child from spreading impetigo to other parts of the body, the doctor or nurse will probably recommend covering infected areas of skin with gauze and tape or a loose plastic bandage. Keep your child's fingernails short and clean to prevent scratching that could lead to infection.

Prevention

Keeping skin clean can help prevent impetigo. Kids should wash their hands well and often and take baths or showers regularly. Pay special attention to skin injuries (cuts, scrapes, bug bites, etc.), areas of eczema, and rashes such as poison ivy. Keep these areas clean and covered.

Anyone in your family with impetigo should keep fingernails cut short and the impetigo sores covered with gauze and tape.

Prevent impetigo infection from spreading among family members by making sure everyone uses their own clothing, sheets, razors, soaps, and towels. If necessary, substitute paper towels for cloth ones until the impetigo is gone. Separate the infected person's bed linens, towels, and clothing from those of other family members, and wash these items in hot water. Keep the surfaces of your kitchen and household clean.

When to Call the Doctor

Call the doctor if your child has signs of impetigo, especially if he or she has been exposed to a family member or classmate with the infection. If your child is already being treated for impetigo, keep an eye on the sores and call the doctor if the skin doesn't begin to heal after 3 days of treatment or if a fever develops. If the area around the rash becomes red, warm, or tender to the touch, notify the doctor as soon as possible.

Reviewed by: Rupal Christine Gupta, MD
Date reviewed: June 2014