Impetigo: causes, symptoms, diagnosis and treatment

Impetigo: causes, symptoms, diagnosis and treatment

Introduction: Impetigo is a highly contagious bacterial skin infection that commonly affects children, although it can occur in people of all ages. This article will provide a comprehensive overview of impetigo: causes, symptoms, diagnosis and treatment options. Additionally, we will explore importance of hygiene practices to help reduce the risk of impetigo outbreaks as well as complications associated with impetigo.


What is Impetigo?

Impetigo is a superficial skin infection that primarily affects the outermost layer of the skin, known as the epidermis. It is characterized by the development of red sores or blisters that can break open, ooze fluid, and eventually form yellowish-brown crusts. The infection is highly contagious and can spread through direct contact with an infected individual or by touching contaminated objects.

Types of Impetigo

There are two main types of impetigo, each with distinct characteristics:

  1. Non-bullous impetigo: Non-bullous impetigo is the most common form, accounting for about 70% of all cases. It typically starts as small, red sores that quickly evolve into blisters or vesicles. These blisters are fragile and easily rupture, leaving behind moist, red patches that gradually form a thick, honey-colored crust.
  2. Bullous impetigo: Bullous impetigo is less common than non-bullous impetigo, accounting for approximately 30% of cases. It primarily affects infants and children. This form is characterized by the presence of large, fluid-filled blisters that are clear or yellow in color. These blisters are often surrounded by a red and inflamed area of skin and may leave behind a thin, fragile, and light brown crust.

Causes of Impetigo

Impetigo is primarily caused by two types of bacteria: Staphylococcus aureus (S. aureus) and Streptococcus pyogenes (group A Streptococcus). These bacteria can enter the body through breaks in the skin, such as cuts, scratches, or insect bites. The most common causes and risk factors for impetigo include:

  • Poor hygiene: Lack of proper hygiene practices, such as inadequate handwashing or sharing personal items like towels or clothing, can contribute to the spread of impetigo-causing bacteria.
  • Skin injuries: Skin injuries, such as cuts, abrasions, or insect bites, provide an entry point for bacteria, increasing the risk of impetigo.
  • Warm and humid climates: Impetigo is more prevalent in warm and humid climates, as these conditions create an environment conducive to bacterial growth and transmission.
  • Crowded living conditions: Impetigo is more likely to occur in settings where people live in close proximity, such as schools, daycare centers, or military barracks, due to the ease of bacterial transmission.
  • Compromised immune system: Individuals with weakened immune systems, such as those with HIV/AIDS, diabetes, or other chronic illnesses, are more susceptible to developing impetigo.


Symptoms of Impetigo

Recognizing the common symptoms of impetigo, including the presence of red sores or blisters, honey-colored crusts, and itching, is crucial for early identification and appropriate management. Impetigo typically manifests with the following symptoms:

  • Red Sores or Blisters: The primary symptom of impetigo is the appearance of red sores or blisters on the skin. These sores are often small, round, and may be itchy or painful. They can occur anywhere on the body but are commonly found on the face, particularly around the nose and mouth, as well as the hands and arms.
  • Ruptured Blisters: The blisters associated with impetigo are fragile and can easily burst, leaving behind a moist, red base.
  • Honey-Colored Crusts: After the blisters burst, a characteristic feature of impetigo is the formation of thick, golden-yellow or honey-colored crusts. These crusts can be itchy and may increase in size if left untreated.
  • Itching and Discomfort: The affected area may experience itching, pain, or discomfort, leading to scratching and potential further spread of the infection.
  • Swollen Lymph Nodes: In some cases, impetigo can cause nearby lymph nodes, such as those in the neck or groin, to become swollen and tender.
  • Contagiousness: Impetigo is highly contagious, and close contact with an infected individual or contaminated objects can easily spread the infection to others.


Diagnosis of Impetigo

The diagnosis of impetigo is primarily based on a physical examination conducted by a healthcare professional. During the examination, the healthcare provider will assess the appearance of the skin lesions and look for characteristic signs of impetigo, such as red sores, blisters, and honey-colored crusts. They may also inquire about symptoms like itching or pain.

The healthcare provider will carefully examine the affected areas and check for any signs of spreading or complications, such as lymph node enlargement or deeper skin involvement. They may also inquire about the patient’s medical history, recent exposure to other individuals with impetigo, and any underlying health conditions that may increase the risk of complications.

Laboratory Tests:

In most cases, laboratory tests are not necessary for diagnosing impetigo. However, they may be performed in certain situations, especially when the diagnosis is uncertain or if complications are suspected. The following laboratory tests may be utilized:

  1. Bacterial Culture: A bacterial culture involves taking a sample from the skin lesion and sending it to a laboratory for analysis. This test helps identify the specific bacteria causing the impetigo infection and determine the most effective antibiotic treatment.
  2. Polymerase Chain Reaction (PCR): PCR is a molecular technique that can detect the genetic material (DNA) of bacteria. It may be used to identify the presence of specific bacteria, such as Staphylococcus aureus or Streptococcus pyogenes, in cases where the diagnosis is unclear or if there is a need to confirm the bacterial species causing the infection.

While laboratory tests can provide valuable information, they are not routinely required for diagnosing uncomplicated cases of impetigo. The diagnosis is usually based on the characteristic appearance of the skin lesions and the patient’s clinical presentation.


Treatment of Impetigo
  1. Topical Antibiotics:

Topical antibiotics are the first line of treatment for mild to moderate cases of impetigo. These medications are applied directly to the affected skin to eliminate the bacteria causing the infection. Common topical antibiotics used for impetigo treatment include:

1.1. Mupirocin: Mupirocin is an effective topical antibiotic that specifically targets the bacteria responsible for impetigo. It is usually applied three times a day for 7 to 10 days.

1.2. Fusidic Acid: Fusidic acid is another commonly prescribed topical antibiotic for impetigo treatment. It is typically applied two to three times a day for 7 to 10 days.

It is essential to follow the healthcare provider’s instructions regarding the application of topical antibiotics, including the duration of treatment and any specific precautions.

  1. Oral Antibiotics:

In cases where the impetigo infection is widespread, severe, or fails to respond to topical antibiotics, oral antibiotics may be prescribed. Oral antibiotics are taken by mouth and help to eradicate the bacteria from the body. Commonly prescribed oral antibiotics for impetigo treatment include:

2.1. Oral Dicloxacillin or Cephalexin: These antibiotics are often used to treat impetigo caused by Staphylococcus aureus bacteria.

2.2. Oral Penicillin or Amoxicillin: These antibiotics are effective against impetigo caused by Streptococcus pyogenes bacteria.

The duration of oral antibiotic treatment may vary, but it typically lasts for 7 to 10 days. It is crucial to complete the full course of antibiotics as prescribed by the healthcare provider, even if the symptoms improve.


Importance of Good Hygiene Practices

In addition to medication, maintaining good hygiene practices is essential for the successful treatment of impetigo and prevention of its spread. Here are some important hygiene practices to follow:

  • Regular Handwashing: Thoroughly wash your hands with soap and water, especially before and after applying medication, touching the affected area, or coming into contact with potentially contaminated surfaces.
  • Gently Cleanse the Affected Area: Use mild soap and warm water to cleanse the impetigo-affected skin. Gently remove any crusts or discharge to aid in healing and prevent the spread of bacteria.
  • Avoid Scratching or Picking: Encourage the affected individual, especially children, to avoid scratching or picking at the impetigo sores. This can help prevent the infection from spreading to other parts of the body or causing further complications.
  • Use Disposable Items: Use disposable tissues or paper towels to cover the affected areas or to clean any discharge. Avoid using shared towels or clothing to prevent the spread of bacteria.
  • Launder Clothing and Linens: Wash any clothing, towels, or bedding that comes into contact with the impetigo sores in hot water to kill bacteria and prevent reinfection.


Complications Associated with Impetigo

Although impetigo is generally a mild and self-limiting condition, complications can arise in some cases, especially if left untreated or if the infection spreads to other parts of the body. The following are potential complications associated with impetigo:


  • Cellulitis: If the infection spreads beyond the initial site and penetrates deeper layers of the skin, it can lead to cellulitis. Cellulitis is characterized by redness, warmth, swelling, and tenderness of the affected area. Prompt medical attention is required to prevent further complications.
  • Lymphangitis: The bacteria causing impetigo can invade the lymphatic vessels, leading to lymphangitis. This condition is characterized by red streaks on the skin, extending from the infected area to nearby lymph nodes. Lymphangitis requires immediate medical treatment.
  • Ecthyma: Ecthyma is a more severe form of impetigo that affects the deeper layers of the skin. It is characterized by painful, ulcerative sores with a thick, gray or yellowish crust. Ecthyma can result in scarring and may require more aggressive treatment than typical impetigo.
  • Post-streptococcal Complications: In rare cases, impetigo caused by Streptococcus pyogenes bacteria can lead to post-streptococcal complications, such as acute glomerulonephritis (a kidney condition) or rheumatic fever (an inflammatory disease affecting the heart, joints, and other organs).



Impetigo can be a distressing condition, but with proper understanding of its causes, symptoms, and available treatment options, you can effectively manage and prevent its recurrence. While conventional treatment is often necessary, natural remedies can also play a valuable role in alleviating symptoms and supporting the healing process. By adopting good hygiene practices and taking preventive measures, you can reduce the risk of impetigo and promote overall skin health.

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