(Click the link to comment and to vote – voting not working through email, sorry!)

You are seeing a previously healthy 9-month old boy brought in for rash. The child had 3 days of fever. He was seen yesterday evening at an urgent care and diagnosed with otitis media and prescribed amoxicillin. He has never taken any antibiotics before. This morning, his fever was gone, but he developed a blanching pink maculopapular rash on the torso that spread to the extremities and face later in the afternoon. He does not seem to be itchy. He has been well appearing and eating normally throughout his illness. 

What is the most likely cause of his rash?
14 votes