My grandmother was allergic to some jewelry --
gold, I think -- and her wedding ring had
to be platinum
to avoid rashes. I never saw the rash, so don't know what it looked like. She could also have been allergic to whatever the gold was mixed with to make it hard, and in those days (half a century ago) I don't think the dermatological testing was that precise. Just a thought. (PS she lived in the woodsy part of the country, so who knows, maybe she had Lyme! Dunno.