Dropped spike icon should be fairly easy to spot - it's pretty large compared to the other icons. Let me know if there are cases where that's not true because of color or overlapping.
I believe OP was talking about in game, not on the minimap.
In game the spike is really dull, doesn't really stand out on screen in a pile of bodies/guns/grey floor.
It would be nice if it was brighter or had a larger glow and stood out more in the environment.
Oh, yes. I've seen some upcoming changes that do a better job of highlighting dropped items.