Health Library

What Is Impetigo?

Impetigo (im-peh-TY-go) is a very common bacterial skin infection among kids, especially preschoolers and school-age kids. It can cause blisters or sores, is not usually serious, and improves with antibiotic treatment.

What Causes Impetigo?

Two types of bacteria — Staphylococcus aureus and group A streptococcus (which also causes strep throat) — usually cause impetigo. Methicillin-resistant Staphylococcus aureus (MRSA) is also becoming an important cause of impetigo.

Kids can be more likely to develop impetigo when their skin is already irritated by another problem, such as eczema, poison ivy, insect bites, and cuts or scrapes. Bacteria that usually live harmlessly on the skin can get into the body through the area of broken skin, leading to symptoms of impetigo. Scratching a sore or a rash is a common cause — for example, poison ivy can get infected and turn into impetigo. It also happens more often in warm, humid environments. Making sure that kids wash their hands and faces well can help prevent it.

What Are the Signs & Symptoms of Impetigo?

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

The three types of impetigo are non-bullous (crusted), bullous (large blisters), and ecthyma (ulcers):

• Non-bullous or crusted impetigo is most common. It 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 area, making it look like it has been coated with honey or brown sugar.
• Bullous impetigo causes larger fluid-containing blisters that look clear, then cloudy. These blisters are more likely to stay longer on the skin without bursting.
• Ecthyma (ek-THY-muh) impetigo looks like “punched out” ulcers with yellow crust and red edges.

Is Impetigo Contagious?

Impetigo is contagious, and can spread to anyone who touches infected skin or items that have touched infected skin (such as clothing, towels, and bed linens). It can be itchy, so kids also can spread the infection when they scratch it and then touch other parts of their body.

How Is Impetigo Diagnosed?

In most cases, doctors can diagnose impetigo based on how the rash looks. Occasionally, they may need to take a sample of fluid from blisters for testing.

How Is Impetigo Treated?

Impetigo is typically treated with antibiotics, either as a cream/ointment to put on skin or a medicine taken by mouth:

• When it just affects a small area of the skin (and especially if it’s the non-bullous form), impetigo is treated with antibiotic ointment for 5 days.
• 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.

After antibiotic treatment begins, healing should start within a few days. It’s important to make sure that your child takes the medicine as prescribed. Otherwise, a deeper and more serious skin infection could develop. Other problems that group A strep can cause if impetigo is not properly treated include rheumatic fever (which can damage the heart) and kidney disease.

While the infection is healing, gently wash the 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 (you don’t have to remove all of it).

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

Children can usually return to school or daycare 24 hours after starting treatment.

Can Impetigo Be Prevented?

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 their fingernails cut short and the impetigo sores covered with gauze and tape.

To prevent impetigo from spreading among family members, make sure everyone uses their own clothing, sheets, razors, soaps, and towels. Separate the bed linens, towels, and clothing of anyone with impetigo, and wash them in hot water. Keep the surfaces of your kitchen and household clean.

When Should I Call the Doctor?

Call the doctor if any of your kids have signs of impetigo, especially if they’ve been around 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, call the doctor right away.