A 6-yeаr-оld bоy is brоught to the clinic by his mother for а rаsh around his nose and mouth. She reports that the rash started as small red bumps that developed into pus-filled lesions. On examination, the nurse practitioner notes several small vesicles and pustules with a thick, golden-yellow crust. The child is otherwise healthy and afebrile. Which description best fits this patient’s condition?