A 6-year-old girl presents with a history of 4 days of fever, headache, rash, and sore throat. The rash is maculopapular, blanching, with a sandpaper-like texture and located on the cheeks, axillae, and the trunk. Tonsillar erythema and exudates are noted along with an erythematous oropharynx and strawberry tongue. The lips and conjunctiva are normal. What is the most appropriate management