D.G.
Sounds like Roseola. My eldest son had it when he was 11 months old and my second son, who is 19 months old, just had it last week. High fever for several days, and once the fever has stopped then a rash breaks out and slowly spreads and intensifies starting at the belly and then travelling all over. The spots should go away within a week. They shouldn't cause him much if any discomfort. If not Roseola, it isn't uncommon for high fevers to cause rashes. It could also be a strep infection. I saw that some suggested Fifth's Disease. Technically he is too young, and you would have seen more of a slapped/red cheek to begin with (we've had that too). Good luck!