Can beers that have been brewed with nuts trigger anaphylaxis?

Yes: People with nut allergies can be highly sensitive to even the tiniest amounts. If you have such an allergy (it is rarely ALL nuts, since peanuts and other kinds of nuts are actually from very different kinds of plants), avoid ANYTHING that might have nuts. A young woman athlete at Brown university died of anaphylaxis after eating chili that had been thickened with peanut butter. Carry epi-pen!

Yes but: it depends on the nut you are allergic to. I don't believe there has been a study deciphering whether the fermentation process in beer affected the allergenicity of the nuts. The best practice is avoidance until proven otherwise. A visit to an allergist will likely help you unravel the puzzle.