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 due to minor trauma.

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).

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.

The two types of impetigo are bullous impetigo (large blisters) and non-bullous impetigo (crusted) impetigo. The non-bullous or crusted form is most common. It's usually caused by S. aureus but can also be caused by infection with group A streptococcus. Non-bullous begins as tiny blisters, which eventually burst and leave small wet patches of red skin that may weep fluid. Gradually, a tan or yellowish-brown 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 may itch and kids can spread the infection by scratching it and then touching other parts of the body.

Impetigo is contagious and 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.

Treatment

When it just affects a small area of the skin (and especially if it is the non-bullous form), impetigo can usually be 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, which is generally 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 the doctor has 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 in 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.

Prevention

Good hygiene practices, such as regular hand washing, can help prevent impetigo. Have kids use soap and water to clean their skin and be sure they take baths or showers regularly. Pay special attention to areas of the skin that have been injured, such as cuts, scrapes, bug bites, 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 using antibacterial soap and making sure that each family member uses a separate towel. 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. And 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: Yamini Durani, MD
Date reviewed: May 2011