do you have to have direct contact with a poisonous mushroom for its toxins or carcinogens to harm you
Certified GKH Gardening Expert
Even further... It must be digested in order to have any affects imparted on you. Otherwise, they are absolutely harmless to touch.
There are several absolutely deadly mushrooms that have popped up in my plants indoors, but I always leave them. They do much more good than harm for your plant. As long as you do not eat a toxic mushroom, then there will be no reason to fear it. Even then, many toxic mushrooms are only mildly toxic, so your chances of being injured by a mushroom quietly living on its own are very close to nonexistent.
I find it fascinating to watch them grow, and change since they do so very quickly!