Q: Does numbing traps reduce damage from elite affixes? The numbing traps passive text reads: 
Enemies you Slow or hit with Fan of Knives, Spike Trap, Caltrops, Grenades,
and Sentry fire have their damage reduced by 25% for 3 seconds.

Does this damage reduction apply to elite affixes? Is it only melee attacks? What about boss area of effects, Malthael's white poo for instance?

A: I once used this when I was fighting Malthael on T6 because he kept killing me. I had less gear then :)
This in conjunction with several other damage reducers helped to survive the fire spray he does in his last phase.
Yes, this damage reduction does apply to elite affixes such as jailor, and bosses as well, such as Malthael's firethrowing aoe he does (note: after multiple fights I have realized he never hits the left healing well with it, so you can stand there if you want to avoid it).
Numbing traps, while in my opinion not viable because you lose damage to use it, does a good job in reducing damage especially when you have a lot of turrets out.
A better route to go if playing solo and you have the gear is to have a templar with the invincibility token and you and your templar both wear a unity ring.
