Nickel sensitivity is common, and since gold and silver alloys usually contain nickel, it may seem that the person is sensitive to the gold or silver.
Simply Whispers is a brand of jewelry without nickel. Mostly they sell earrings, but there is some other jewelry as well. Their jewelry is either surgical steel, 24K gold over surgical steel, or precious metals without nickel.
http://simplywhispers.stores.yahoo.net/