A 10-yeаr-оld child hаs а 1-week histоry оf fever of 104°C that is unresponsive to antipyretics. The primary care pediatric nurse practitioner examines the child and notes bilateral conjunctival injection and a polymorphous exanthema, with no other symptoms. Lab tests show elevated ESR, CRP, and platelets. Cultures are all negative. What will the nurse practitioner do?