Cheesemongers call it “Parm arm,” the itchy rash they sometimes get from breaking down a whole wheel of Parmigiano Reggiano. I’ve never had that experience, but Parmigiano Reggiano and some other aged cheeses can make my tongue burn. Ouch. It’s really unpleasant. And I’m not alone in this reaction. My husband never feels the burn, but others do, and last week I learned more about what causes it.