Uniform patches of small red dots on skin?

I found small patches of red dots on both of my outer thighs and both fronts of my shoulders (in the same place on both sides in both cases). They aren't bumpy at all and don't itch, feel uncomfortable, or hurt when I touch them. As far as I know I'm not allergic to anything and I don't have allergies, but I have been sick lately with what feels like a sinus infection. What could they be? Are they harmful?