Nonbullous impetigo is typically associated with which organism?

• A. Staphylococcus aureus
• B. Group A Streptococcus
• C. Streptococcus pneumoniae
• D. Pseudomonas aeruginosa

Answer: (B)

Impetigo that presents without bullae is most commonly caused by Group A Streptococcus (Streptococcus pyogenes). This organism is classically associated with the honey-colored crusts that form after the vesicles rupture, especially on the face and extremities. While Staphylococcus aureus can also contribute to nonbullous impetigo in some cases, the typical/more common association for this nonbullous form is Group A Streptococcus. Bullous impetigo, by contrast, is more often linked to Staphylococcus aureus due to its exfoliative toxin. The other organisms listed are not classic pathogens for impetigo.