What to do!

How do you find out if someone is allergic to natural fibers? I want to make a prayer shawl for my daughter's teacher, but I want to give her something that she will actually use and not sneeze every time she looks at it. If I go the safe (and cheaper) route, I could easily make something out of Lionbrand Homespun. If I go the nicer (and more expensive) route, I could use Berocco Ultra Alpaca, which I like more! Oh well, guess I'll check the finances and that will decide for me!