What are the exam findings for Impetigo (Impetigo, a highly contagious bacterial skin infection)?

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From the Guidelines

Impetigo is characterized by honey-colored crusts over erythematous bases, typically on exposed areas like the face, especially around the nose and mouth, or extremities, with bullous impetigo showing fluid-filled vesicles or bullae that rupture, leaving behind thin, yellow crusts 1. The primary exam findings for Impetigo include:

  • Honey-colored crusts over erythematous bases
  • Fluid-filled vesicles or bullae that rupture, leaving behind thin, yellow crusts in bullous impetigo
  • Lesions are typically found on exposed areas like the face, especially around the nose and mouth, or extremities
  • The affected skin may be pruritic or painful, and regional lymphadenopathy might be present
  • Systemic symptoms are usually absent unless there's a more severe infection Impetigo is most commonly caused by Staphylococcus aureus or group A Streptococcus, and diagnosis can be confirmed by Gram stain and culture of the pus or exudates from skin lesions 1. Treatment for impetigo should include topical mupirocin or retapamulin applied twice daily for 5 days for mild cases, while more extensive infections require oral antibiotics like cephalexin or dicloxacillin for 7 days 1. It is essential to advise patients to avoid touching or scratching lesions to prevent spread, use separate towels and linens, and maintain good hygiene with regular handwashing to prevent complications like cellulitis, lymphangitis, or post-streptococcal glomerulonephritis 1.

From the FDA Drug Label

CLINICAL STUDIES The efficacy of topical mupirocin ointment in impetigo was tested in two studies. The exam findings for Impetigo are not directly stated in the provided drug label. Key points:

  • The label discusses the efficacy of mupirocin ointment in treating impetigo, but does not describe the exam findings for the condition.
  • Clinical efficacy rates and pathogen eradication rates are provided, but these are outcomes of treatment, not exam findings. 2

From the Research

Exam Findings for Impetigo

The exam findings for Impetigo, a highly contagious bacterial skin infection, can be summarized as follows:

  • Nonbullous impetigo (70% of cases) is characterized by honey-colored crusts on the face and extremities 3, 4, 5
  • Bullous impetigo (30% of cases) results in large, flaccid bullae and is more likely to affect intertriginous areas 3, 4
  • The classic appearance of distinctive honey-colored, crusted legions aids in diagnosis, which is most often based on clinical presentation 4
  • Impetigo primarily affects the skin or secondarily infects insect bites, eczema, or herpetic lesions 3
  • The disease is generally mild and felt to be self-limited; however, antimicrobial treatment is often initiated to reduce spread and shorten clinical course 4, 5

Types of Impetigo

The two principal types of Impetigo are:

  • Nonbullous impetigo, caused by Staphylococcus aureus or Streptococcus pyogenes 3, 4, 5
  • Bullous impetigo, caused exclusively by S. aureus 3, 4

Diagnosis and Treatment

Diagnosis is usually made clinically, but rarely a culture may be useful 5 Treatment options include:

  • Topical antibiotics such as mupirocin, retapamulin, and fusidic acid 3, 6, 5
  • Oral antibiotic therapy for extensive cases or when topical therapy is impractical 3, 6, 5

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Impetigo: diagnosis and treatment.

American family physician, 2014

Research

Impetigo.

Advanced emergency nursing journal, 2020

Research

Diagnosis and treatment of impetigo.

American family physician, 2007

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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