A 9 months-old female patient presented with a history of fever in the previous 5 days (39,5ºC), that only last 3 days. Two days ago, a non-pruritus exanthema developed, beginning at the chest and progressing towards the face and the cervical area, as shown in the pictures.

Question:
Based on the clinical presentation and the dermatological findings, which one is the most likely diagnosis?