I'm amazed that people pick them up .All spiders can bite and some bites are very painful.
Particularly the red spiders that eat woodlice. Their bite feels like a wasp sting .I can attest to this as I once trod on one which sank its fangs into the sole of my foot through the thick bit of skin.
All spiders inject a solution which dissolves the tissues of their victims so that they can 'suck' the innards . This mild venom can set up a nasty painful infection under the skin somewhat akin to a wasp or bee sting.
you might want to think about that the next time you pick one up