What is impetigo?

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From the Guidelines

Impetigo is a common bacterial skin infection that primarily affects children, though adults can also get it, and is caused by Staphylococcus aureus or Streptococcus pyogenes bacteria, with treatment usually involving topical antibiotics like mupirocin or retapamulin twice daily for 5 days, as recommended by the Infectious Diseases Society of America 1.

Overview of Impetigo

Impetigo is a highly contagious infection that typically presents as red sores that quickly rupture, ooze for a few days, then form a yellowish-brown crust. These sores usually appear around the nose, mouth, and on exposed skin of the face and limbs. There are two main types: non-bullous impetigo (the most common form with honey-colored crusts) and bullous impetigo (which forms fluid-filled blisters).

Causes and Risk Factors

Impetigo is caused by Staphylococcus aureus or Streptococcus pyogenes bacteria. The infection can spread through direct contact with the lesions or through items that have come into contact with the bacteria, such as towels or clothing.

Treatment and Management

  • Topical antibiotics: For limited infections, topical antibiotics like mupirocin (Bactroban) or retapamulin (Altabax) applied twice daily for 5 days are recommended 1.
  • Oral antibiotics: More widespread cases may require oral antibiotics such as cephalexin (25-50 mg/kg/day divided into four doses for children) or dicloxacillin for 7 days 1.
  • Good hygiene practices: Washing the affected areas with soap and water, using separate towels, and avoiding touching or scratching the sores are essential to prevent spreading the infection to others or to other parts of the body.

Complications

Without proper treatment, impetigo can lead to complications like cellulitis or, rarely, post-streptococcal glomerulonephritis. It is essential to seek medical attention if the infection does not improve with treatment or if it spreads to other parts of the body.

Prevention

Preventing the spread of impetigo involves practicing good hygiene, such as washing hands frequently, avoiding sharing personal items, and keeping the affected areas clean and covered.

In terms of the most recent and highest quality study, the 2018 WSES/SIS-E consensus conference recommendations for the management of skin and soft-tissue infections provide guidance on the treatment of impetigo, emphasizing the use of antibiotics against Gram-positive bacteria and the importance of incision and drainage for simple abscesses or boils 1. However, the specific treatment recommendations for impetigo are most strongly supported by the 2014 update by the Infectious Diseases Society of America 1.

From the FDA Drug Label

INDICATIONS AND USAGE Mupirocin ointment, 2% is indicated for the topical treatment of impetigo due to: Staphylococcus aureus and Streptococcus pyogenes. The FDA drug label does not answer the question of what impetigo is, but it does indicate that impetigo is a condition that can be treated with mupirocin ointment, 2%, and that it is caused by Staphylococcus aureus and Streptococcus pyogenes 2.

  • Impetigo is not defined in the provided drug labels. No conclusion can be drawn about what impetigo is from the provided information.

From the Research

What is Impetigo

Impetigo is a highly contagious bacterial skin infection that primarily affects children, but can also occur in adults. It is caused by Staphylococcus aureus or Streptococcus pyogenes, alone or in combination 3, 4, 5, 6, 7.

Types of Impetigo

There are two main types of impetigo:

  • Nonbullous impetigo (70% of cases), also known as impetigo contagiosa, which is characterized by honey-colored crusts on the face and extremities 3.
  • Bullous impetigo (30% of cases), which is caused exclusively by S. aureus and results in large, flaccid bullae, more likely to affect intertriginous areas 3.

Symptoms and Treatment

Impetigo is typically an acute, self-limited disease, but can become chronic in some cases 4. Symptoms include purulent, crusted lesions, which can be treated with topical antibiotics such as mupirocin, retapamulin, and fusidic acid 3, 6. Oral antibiotic therapy can be used for more severe cases or when topical therapy is impractical 3. Treatment options also include natural therapies, such as tea tree oil and Manuka honey, although their effectiveness is not well-established 3.

Complications and Prevention

Complications of impetigo are rare, but can include poststreptococcal glomerulonephritis 3. Prevention measures include good hygiene practices, such as washing hands regularly and avoiding close contact with infected individuals 4. An evidence-based treatment algorithm has been developed to address the treatment of impetigo, taking into account antimicrobial resistance and stewardship 7.

Key Points

  • Impetigo is a highly contagious bacterial skin infection caused by S. aureus or S. pyogenes 3, 4, 5, 6, 7.
  • There are two main types of impetigo: nonbullous and bullous 3.
  • Treatment options include topical antibiotics, oral antibiotic therapy, and natural therapies 3, 6, 7.
  • Prevention measures include good hygiene practices and avoiding close contact with infected individuals 4, 7.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Impetigo: diagnosis and treatment.

American family physician, 2014

Research

NVC-422 topical gel for the treatment of impetigo.

International journal of clinical and experimental pathology, 2011

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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