From The Wall Street Journal (through Pat Kiernan of NY1)
"Yet thousands of women (to judge by postings on the Internet) and a growing number of men develop what's officially called "wedding-ring dermatitis"—not to be confused with the "seven-year itch"—and it can happen suddenly after years of ring-wearing bliss...Nickel allergies have been on the rise in North America in recent years and now affect 24% to 36% of women and 7% to 15% of men, according to the North American Contact Dermatitis Group, which named nickel the 2008 "Allergen of the Year." Women are more likely to have pierced ears, which can facilitate a sensitivity to nickel if earrings containing the metal contact broken skin. But men are closing the gap due to the popularity of body piercing."
More here from WSJ.