Nathaniel C. Cevasco
Humans are natural hosts for many bacterial species that colonize the skin as normal flora.Staphylococcus aureus and Streptococcus pyogenes are infrequent resident flora, but they account for a wide variety of bacterial pyodermas. Predisposing factors to infection include minor trauma, preexisting skin disease, poor hygiene, and, rarely, impaired host immunity.
Definition and Etiology
Impetigo is a superficial skin infection usually caused by S. aureus and occasionally by S. pyogenes.
Prevalence and Risk Factors
Impetigo affects approximately 1% of children.
Pathophysiology and Natural History
S. aureus produces a number of cellular and extracellular products, including exotoxins and coagulase, that contribute to the pathogenicity of impetigo, especially when coupled with preexisting tissue injury. Impetigo commonly occurs on the face (especially around the nares) or extremities after trauma.
**Also included in this article:
Folliculitis, Furunculosis, Carbunculosis, Candidiasis, Ecthyma, Erysipelas, Cellulitis, Necrotizing Fasciitis, Dermatophytosis, Herpes Zoster, Tinea (Pityriasis) Versicolor, Viral infections**