Roseola.net

I am a young adult and I have symptoms that point to the infant viral infection roseola http://www.kidshealth.org/parent/infections/skin/roseola.html
I had a high fever, fatigue, and small red bumps (not blistery, that are warm) on in the inside of my arms, back of my legs and some on my neck and stomach.
I did not eat anything new or take any new medications, so it probably was not an allergic reaction.
Before symptoms, took a walk for a few miles in 85 degree weather with shade (I can run few miles in hot weather, never had heat stroke.)
Hydrated okay.
When I am feverish, the bumps are more red and hot.
One of my hands (back and front), the palm area is swollen, hot, and red. Unlike the rash.
A few days earlier, I strained my neck by messenger back and bruised area around jugular.
No coughing, sore throat, runny nose.
Not sexually active.

All suggestions of possible cause appreciated. Thanks.