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Impetigo: Blisters and crusts on a child’s face are common signs of impetigo.

Impetigo: overview

Also called school sores

Impetigo (im-peh-tie-go) is a common skin infection, especially in children. It’s also highly contagious.

Most people get impetigo through skin-to-skin contact with someone who has it. Children and athletes like wrestlers and football players often get it this way.

It’s also possible to get it by using something infected with the bacteria that cause impetigo. You can get it from an infected towel or sports equipment. Wearing infected clothing is another way to get impetigo.

Staph and strep cause most cases of impetigo. These bacteria cause impetigo by getting into the body. They can get in through a cut, scratch that barely breaks the skin, or bug bite. A rash, sore, or burn also provides a great entry point for the bacteria.

A child may get impetigo by scratching itchy eczema or chickenpox. The scratching breaks the skin, making it easy for the bacteria to get inside.

Sometimes impetigo develops on unbroken skin.

Treatment can quickly cure impetigo.

While highly contagious, impetigo is rarely serious. It often clears on its own in a few weeks.

Treatment, however, is recommended. By treating it, you reduce your risk of developing complications. Without treatment, the infection can cause new sores or blisters to develop for several weeks. The infection can also go deeper into the skin. This can be serious.

Treatment also reduces your risk of spreading impetigo to others.

Image used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides.


Craft, N, Lee PK, et al. “Superficial cutaneous infections and pyodermas.” In: Wolff K, Goldsmith LA, et al. Fitzpatrick’s Dermatology in General Medicine (seventh edition). McGraw Hill Medical, New York, 2008: 1695-8.
Halpern AV and Heymann WR. “Bacterial diseases.” In: Bolognia JL, et alDermatology. (second edition). Mosby Elsevier, Spain, 2008:1075-6.

Impetigo: Signs and symptoms

What you see and feel differs with the type of impetigo. There are 2 types.

Impetigo on 5-year-old girl’s leg: The sore has broken open, so you see redness and honey-colored crusts.

Non-bullous impetigo: This is the most common type. It goes through these stages:

The infection can spread to other areas of the body, where you’ll see this process begin all over again. This is one reason treatment is so important.

Bullous impetigo: This type causes fluid-filled blisters, but without redness on the surrounding skin. When a person has bullous impetigo, you’ll see it progress as follows:

Bullous impetigo on 12-year-old girl’s arm: This type causes painless, fluid-filled blisters.

Bullous impetigo on boy’s knee: The blisters have ruptured, leaving crusty sores

Ecthyma: Ecthyma (ec-thy-ma) can develop when impetigo goes untreated. This is a more serious type of infection because it goes deeper into the skin. When a person has ecthyma, you’ll see:

Ecthyma: This began as a pus-filled blister on top of an insect bite and turned into the open sore you see here.

Because the infection goes deeper into the skin, you may see scars once the skin heals.

If notice any of these signs on your child’s skin (or your own skin), you should see your dermatologist, pediatrician, or family doctor. All types of impetigo are very contagious.

Treatment can help clear the infection and prevent the infection from spreading to others.

Images used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides.


Habif TP, Campbell, JL, et al. “Impetigo.” In: Dermatology DDxDeck. Mosby Elsevier, China, 2006: Card#46.
Tuchman M and Weinberg JM. “Bacterial infections.” In: Kelly AP and Taylor S. Dermatology for Skin of Color. (first edition). The McGraw-Hill Companies, Inc. China, 2009:413-4.

Impetigo: Who gets and causes

Kids often have skin-to-skin contact: Impetigo is very contagious and spreads with close contact.

Children aged 2 to 5 years old are most likely to get this extremely contagious skin infection.

Anyone, however, can get impetigo. Older children and adults get it. Adults often catch impetigo from an infected child.

Some athletes have a higher risk of catching it. Because of the skin-to-skin contact in sports like wrestling and football, these athletes often get impetigo. The bacteria that cause impetigo thrive in warm, humid places, so swimmers also have an increased risk.

Summer can catch it from touching an infected surface or sharing a towel with a swimmer who has impetigo.

People who live in hot, humid areas get more cases of impetigo. In the United States, people often catch it in the summer or fall.

What causes impetigo?

Bacteria cause this highly contagious skin infection.

Most people develop it when the bacteria, usually staph or strep, invade injured skin. A scrape on your skin is often enough to get infected. The bacteria may also get in through a cut, insect bite, or anything else that damages the skin. Once inside, the bacteria cause an infection in the top layers of the skin.

Sometimes, the bacteria invade uninjured skin and cause impetigo.

Image from Thinkstock.


Ashack KA, Burton KA et al. “Skin infections among US high school athletes: A national survey.” J Am Acad Dermatol. 2016 Apr;74(4):679-84.
Craft, N, Lee PK, et al. “Superficial cutaneous infections and pyodermas.” In: Wolff K, Goldsmith LA, et al. Fitzpatrick’s Dermatology in General Medicine (seventh edition). McGraw Hill Medical, New York, 2008: 1695-8.
Halpern AV and Heymann WR. “Bacterial diseases.” In: Bolognia JL, et al. Dermatology. (second edition). Mosby Elsevier, Spain, 2008:1075-6.

Impetigo: Diagnosis, treatment, and outcome

How do dermatologists diagnose impetigo?

A dermatologist can often diagnose impetigo by looking at your skin.

Sometimes, lab tests are necessary to give you the diagnosis — or get information necessary to treat you. If you need a lab test, a dermatologist often takes a sample from a blister on your skin. This can tell your dermatologist which bacteria are causing the infection.

If your dermatologist thinks that the infection could be widespread, you may need a blood test.

How do dermatologists treat impetigo?

An antibiotic usually cures impetigo.

Dermatologists often prescribe an antibiotic that you apply to the skin, such as mupirocin (mew-peer-ah-cin) or retapamulin (reh-tah-pa-mu-lin). The U.S. Food and Drug Administration (FDA) has approved retapamulin to treat impetigo in children as young as 9 months old. Mupirocin is FDA approved to treat people 12 years of age and older.

When necessary, a dermatologist may prescribe one of these medicines to treat a child younger than the FDA-approved age. This is called off-label use and is legal. It can also be very helpful.

If a dermatologist prescribes an antibiotic you apply to the skin, you would apply it to the skin with impetigo. If you have several outbreaks of impetigo, you may need to apply it inside the nostrils. The bacteria that cause impetigo often thrive in the nostrils.

Sometimes stronger medicine is necessary. Your dermatologist can prescribe an antibiotic that you take by mouth. A few patients need injections of an antibiotic.

Skin care also plays an important role in clearing impetigo. The following steps are often very helpful:

  1. Soak the skin with impetigo in warm water and soap to gently remove dirt and crusts.
  2. Apply the antibiotic (or other medicine) as prescribed.
  3. Cover the skin with impetigo to help it heal and prevent spreading the infection to others.

If a child gets impetigo frequently, your dermatologist may recommend adding a small amount of bleach to the child’s bath. This is completely safe when you follow the directions. A bleach bath can reduce the amount of bacteria on the skin, which may prevent new infections.

Because impetigo is very contagious, a child may need to stay home from school for a few days. If this is necessary, your dermatologist will tell you when your child can return to school.

Teens and adults need not stay home, but they should take the following precautions to avoid infecting others:

Your dermatologist can tell you how long to take these precautions.

Outcome for impetigo

Dermatologists recommend treating impetigo. It can help cure the impetigo and prevent others from getting this highly contagious skin infection.

With treatment, impetigo is usually no longer contagious within 24 to 48 hours.

Without treatment, impetigo often clears on its own in 2 to 4 weeks. During this time, there is a greater risk of developing complications. You may see new blisters and sores.

It’s also possible for the infection to go deeper into the skin if you don’t treat. If this happens, you can develop ecthyma (ec-thy-ma). This infection goes deeper into the skin than impetigo. As the skin heals from ecthyma, scars can form.

Ecthyma is more common in children, the elderly, and people who have diabetes. It also develops in the homeless and combat soldiers fighting in a hot and humid climate.

If you see anything on your skin that looks infected, it’s best to see a dermatologist as soon as possible. An early diagnosis and treatment can prevent complications and help you feel better.

Craft, N, Lee PK, et al. “Superficial cutaneous infections and pyodermas.” In: Wolff K, Goldsmith LA, et al. Fitzpatrick’s Dermatology in General Medicine (seventh edition). McGraw Hill Medical, New York, 2008: 1695-8.
Habif TP, Campbell, JL, et al. “Impetigo.” In: Dermatology DDxDeck. Mosby Elsevier, China, 2006: Card#46.
Halpern AV and Heymann WR. “Bacterial diseases.” In: Bolognia JL, et al. Dermatology. (second edition). Mosby Elsevier, Spain, 2008:1075-6.

Impetigo: Tips

10 tips to prevent spreading the infection

And some tips to avoid getting it again

Sideline sports activities while you are contagious: Playing sports can spread impetigo to others and to other parts of your body.
Impetigo is very contagious, so it’s easy to spread the disease to other people — and to other parts of your body. To help patients avoid this, dermatologists recommend the following.

10 ways to prevent spreading impetigo to others (and to other parts of your body)

  1. Avoid direct skin-to-skin contact with others. Skin-to-skin contact spreads impetigo. It should be avoided until you’re no longer contagious.

    Impetigo is contagious until either:
    a) The blisters and sores crust over.
    b) You’ve been treating with an antibiotic for 24 to 48 hours.
  2. Resist the urge to touch (and scratch) your sores. When you do this, you can spread the infection to other areas of your body.
  3. Skip sharing personal items with others. It’s possible to get impetigo from sharing a razor, towel, or another object that a person with impetigo has used. Be sure to avoid sharing all personal items, including toys.
  4. Keep the sores clean and covered. Wash the sores with soap and water as often as your dermatologist recommends, and cover them with gauze bandages and tape.
  5. Wash your hands after treating your skin, using the toilet, and when they are dirty. Be sure to use soap and dry your hands well, using with a clean towel or paper towel.
  6. Use a clean washcloth and towel each time you wash. This can help avoid spreading the impetigo to other parts of your body.
  7. Wash all clothing, towels, washcloths, and sheets that you (or your child) has worn or used since getting infected. Wash everything in hot water. Only items that belong to the infected person should be washed together. If you need to wash another family member’s clothes or linens, wash these in a separate load.
  8. Disinfect counters, doorknobs, and other surfaces that the person with impetigo has touched. This can prevent others from getting impetigo.
  9. Trim nails so that they are short. Impetigo can be itchy. Scratching can spread the infection to other parts of the body. Scratching can also tear the skin, which can worsen impetigo. Short nails are less likely to damage the skin.
  10. If the skin itches unbearably, apply an anti-itch medicine. Impetigo can be very itchy, but it’s important to avoid scratching.

Prevent getting impetigo again

Impetigo is extremely contagious, so it may not be possible to avoid getting it again. Doing the following, however, can reduce your risk:

  1. Treat wounds right away. If you (or your child) get a cut, scrape, insect bite, or any other wound, immediately wash it with soap and water. Then apply an antibiotic ointment and a bandage.
  2. Bath or shower after every sports workout, practice, and competition. Be sure to use a cleanser or soap and a clean towel to dry off.
  3. Wash your hands after using the toilet and when they get dirty. Again, you want to use soap. You also want to use a clean towel or paper towel to dry your hands.
  4. Stop sharing personal items like sports equipment, towels, and clothes. These can spread impetigo.
  5. If someone has impetigo:
    a.) Avoid touching the person’s skin
    b.) Avoid touching everything that person has touched, including towels, sheets, toys, and sporting equipment.
  6. Wear clean clothes. Avoid pulling dirty clothes out of the laundry hamper, especially dirty workout clothes.

© 2019 American Academy of Dermatology. All rights reserved. Reproduction or republication strictly prohibited without prior written permission. Use of these materials is subject to the legal notice and terms of use located at

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