Bullous Impetigo. A 7-month-old infant was referred to the emergency department with this lesion that was thought to be an inflicted burn injury (child abuse). Aspiration of the lesion showed gram-positive cocci in clusters on Gram stain and culture was positive for Staphylococcus aureus. Posttraumatic paronychia due to S aureus should also be considered in the differential diagnosis. 

Source: Shah BR, Lucchesi M, Amodio J, Silverberg M. Atlas of Pediatric Emergency Medicine, 2e; 2013.