Impetigo

This vesiculopustular eruption manifests with honey-colored crusted erosions. As it resolves, the crusts can turn brown; hyperpigmentation and scale may be evident (figure). Although the diagnosis can be made clinically, it is helpful to obtain a sample of fluid or pus for Gram staining and culture to identify the culprit organism--usually a Gram-positive bacterium--and its sensitivities (because of the increasing prevalence of methicillin-resistant Staphylococcus aureus). Nasal culture of the patient and family members helps determine whether nasal carriage of S aureus is the source of the infection; up to 20% to 25% of persons carry S aureus in their nares. Nasal carriage of S aureus is treated with intranasal mupirocin or a combination of oral antibiotics that often includes rifampin.