What Is Impetigo?

Medically reviewed by William Truswell, MD

Impetigo is a contagious bacterial skin infection that causes itchy, fluid-filled bumps that break open, forming a honey-colored crust. The infection occurs when your skin comes into contact with certain bacteria. You may be particularly vulnerable to developing the infection if you have broken or irritated skin due to cuts, scrapes, or insect bites.

A healthcare provider can diagnose impetigo by looking at the appearance of your sores during a physical exam. However, they may also choose to order a bacterial culture or a biopsy to confirm the diagnosis in some cases. If you receive a diagnosis for the condition, topical (directly on the skin) treatments or oral antibiotics are the gold standard for treatments.

Anyone can develop impetigo, but it is most common among children between two and five years old. Approximately three million people in the United States are affected by impetigo yearly. That's why knowing the symptoms, learning when to reach out for care, and understanding your treatment options can be so important.

Related:What Is the Difference Between Viral and Bacterial Infection?

Types of Impetigo

Impetigo is classified into three types: non-bullous, bullous, and ecthyma. Each type is based on the appearance of the sores and the bacteria that are causing the infection. Knowing which type you have helps healthcare providers determine the appropriate treatment.

Non-bullous Impetigo

Non-bullous impetigo is the most common type, accounting for approximately 70% of cases. Staphylococcus aureus or Streptococcus pyogenes bacteria are the most common causes.

This type of impetigo usually occurs on broken or irritated skin and appears as small, red sores that quickly develop into pus-filled blisters. The blisters then break open and form a yellow-brown crust. Non-bullous impetigo lesions are usually small and do not involve the deeper layers of the skin.

Bullous Impetigo

Bullous impetigo is caused by a strain of Staphylococcus aureus bacteria that produces toxins that causes large, painless, and fluid-filled blisters. The blisters are usually located on the face, buttocks, trunk, or limbs and can form on broken or intact skin. Bullous impetigo lesions may involve the deeper layers of the skin. That said, they can be more severe and take longer to heal.

Ecthyma

A third type of impetigo, called ecthyma, may develop if impetigo is left untreated. This type of impetigo involves deep layers of the skin and causes painful, ulcer-like sores surrounded by red, inflamed skin. These lesions can leave scars on your skin. Ecthyma typically develops on the ankles, buttocks, feet, and legs.

Symptoms

The main symptom of impetigo is the appearance of red, fluid-filled sores that can be itchy and painful. These sores eventually develop a yellow-brown or honey-colored crust. The surrounding skin may also be swollen, red, and sore. In some cases, fluid-filled blisters may burst easily, leaving wet patches of red, raw skin.

Impetigo can occur anywhere on the skin, but most commonly affects the face, particularly around the mouth and nose. In some cases, there may be additional symptoms, including:

Causes

Two types of bacteria cause impetigo: Streptococcus pyogenes and Staphylococcus aureus. These bacteria live on the skin and in the nose and throat. Impetigo can develop when these bacteria enter the body through a cut, scrape, or other injury to the skin. The bacteria then multiply, causing impetigo symptoms to develop.

Impetigo is highly contagious and spreads through direct contact with infected lesions. This can occur in several ways:

  • Scratching a sore and then touching another area of your body

  • Touching an infected person’s skin (e.g., hugs, kisses, or handshakes)

  • Participating in contact sports, such as football and wrestling

  • Spending time in crowded places, such as daycares or schools

  • Sharing bedding, towels, or clothing with an infected person

Risk Factors

Children between the ages of two and six are at a higher risk of impetigo—though adults can also develop the infection. Certain risk factors can increase your risk of developing impetigo, such as:

  • Poor hygiene

  • Crowded or unsanitary living conditions

  • Living in a warm and humid environment

  • Having certain skin conditions, such as eczema or psoriasis

Related:Infections You Can Catch at the Gym

Diagnosis

Healthcare providers can usually diagnose impetigo by examining the sores during a physical exam. Your healthcare provider may order laboratory tests if they suspect a resistant bacteria is causing the infection, the infection is widespread, or you experience recurrent (repeated) impetigo infections.

Common diagnostic tests for impetigo include:

  • Skin swab: A fluid sample from the blister or sore is collected and sent to the lab to identify the type of bacteria causing the infection.

  • Nasal swab: In cases of recurrent or severe impetigo, a sample of fluids is taken from the nose and sent to the lab to determine if a resistant bacteria, such as MRSA, is causing the infection.

  • Biopsy: A small sample of skin is taken from the area surrounding the infection and examined under a microscope. This test is rarely needed but can help diagnose impetigo in cases where the diagnosis is uncertain.

In most cases, these tests are unnecessary for diagnosing impetigo; healthcare providers can typically use their clinical judgment to diagnose impetigo during a physical exam.

Treatment

The most common treatment for impetigo is antibiotics, which help cure the infection and help prevent it from spreading. Other treatments can also help relieve discomfort while waiting for the infection to clear.

If you have an underlying skin condition that increases your risk of impetigo, such as eczema or psoriasis, treating the underlying condition is essential to promote healing and help prevent future flares (or, episodes) of impetigo.

Antibiotics

The gold standard for impetigo treatment is topical or oral antibiotics. The treatment you receive will depend on the severity of your infection.

  • Topical antibiotics: If your impetigo does not deeply penetrate the skin, antibiotic cream or ointment applied directly to the sores can help eliminate the infection. Common topical antibiotics for impetigo include Centany (mupirocin) and Fucidin (fusidic acid).

  • Oral antibiotics: You may need to take antibiotics by mouth if your infection is widespread or your sores penetrate deep layers of the skin. Common oral antibiotics for impetigo include cephalosporins and macrolides, both of which are anti-bacterial medications.

At-Home Treatments

While impetigo usually requires medical treatment with antibiotics to clear the bacterial infection, some at-home remedies may help soothe pain and discomfort while you wait for the infection to clear. These treatments include:

  • Using warm water soaks: Soak the affected area in warm water or apply wet compresses for 15 to 20 minutes to help relieve itching and burning sensations. Once you're done, gently pat the area dry.

  • Keeping it clean: Gently scrub the affected area with antibacterial soap and a soft washcloth.

  • Covering the area: Cover the affected areas of the skin with a sterile bandage or gauze to keep it clean and prevent the infection from spreading.

How to Prevent Impetigo

Impetigo is highly contagious and spreads easily to other people and body parts. Preventing impetigo involves practicing good hygiene and avoiding skin-to-skin contact with others with the infection. Here are some ways to prevent impetigo:

  • Wash hands frequently with soap and water, especially before and after touching the skin, using the toilet, changing diapers, or handling food

  • Keep any wounds or cuts clean and covered with a sterile bandage

  • Avoid sharing personal items such as towels, clothing, and bedding with others

  • Take a shower or bath regularly, particularly after participating in activities that involve close contact with others

  • Disinfect items or surfaces that may be contaminated with the bacteria that cause impetigo, such as gym equipment, wrestling mats, towels, and clothing

  • Seek medical treatment for any skin condition that increases the risk of impetigo, such as eczema or psoriasis

  • Avoid itching, scratching, and touching the sores as this can prevent symptoms from worsening

Complications

Most cases of impetigo heal without scarring and complications. However, untreated impetigo can lead to complications, such as:

  • Post-streptococcal glomerulonephritis (PGSN): Streptococcus, a type of bacteria that can cause impetigo, can sometimes lead to complications as your body fights impetigo. Symptoms of PGSN can mimic signs of kidney inflammation or damage, including dark, reddish-colored urine, swelling in the face, hands, and feet, decreased urination, fatigue, and high blood pressure.

  • Scarring: In cases where impetigo sores penetrate deep layers of the skin, scarring can occur once the sores heal. This can also happen if you pick or scratch at impetigo sores while the infection is healing.

  • Cellulitis: Impetigo can spread to deeper layers of your skin and cause a bacterial infection known as cellulitis to occur, which causes redness, warmth, and swelling of the affected area.

Living With Impetigo

With proper treatment, most people with impetigo will feel better within a few days, and the infection usually clears within a week or two. If you have symptoms of the infection, it's important to talk to your healthcare provider if symptoms do not clear with treatment. They may recommend specific antibiotics to treat the infection and prevent complications.

Many people with impetigo find symptoms uncomfortable and struggle to resist the urge to itch and scratch the sores. You may find it helpful to take warm baths or apply warm, wet compresses to the affected areas to help relieve itching and discomfort while you wait for the infection to clear. Wrapping the affected area with a sterile bandage or gauze can help you avoid itching the area and prevent the spread of the infection.

Frequently Asked Questions

Is impetigo a form of MRSA infection?

Impetigo is most commonly caused by Staphylococcus aureus or Streptococcus pyogenes bacteria. Some impetigo cases are caused by Methicillin-resistant staph aureus bacteria (MRSA), but most are not.

Do I need to wash sheets with impetigo?

Yes, you should wash sheets, clothing, and towels that have been in contact with impetigo sores to prevent the spreading of the infection. It is also important to avoid sharing personal items like utensils or toiletries to prevent the spread of impetigo.

Does impetigo go away on its own?

Impetigo may go away on its own within a few weeks without treatment, but it is still important to see a healthcare provider for proper diagnosis and treatment. With antibiotic treatment, most impetigo infections clear within a week or two.

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