Vaccine-Preventable Infection?

From lacy and reticular and limited to the cheeks, this rash quickly covered the child’s body and transformed into a solid rash. Your dx?

A 5-year-old boy presented with an asymptomatic lacy, reticular rash of 4-days duration. It began with the appearance of a solid red rash on his cheeks. The next day the lacy rash covered his entire body and the solid rash on his cheeks also became lacy.

What's your diagnosis?