I them all besides the A. genticulata
You have to worry about them any time you are working around the spider or in the cage. It bothers some people really bad, doesn't affect others.
Me... My LPs will make me itch when working with them. If I touch their bowls, molts etc. I'll get blisters under my skin on my hands.
Same with my. B. smithi. The others are still to small to tell.
Now take into account that when I'm working with them, I'm working with a lot of spiders :p
A pair of latex gloves wouldn't be a bad idea. After a rehousing, dumping the old substrate into a trash can outside would be another good idea.
There are some people out there that will only keep Old World because of the hairs.