Relationship between cobalt and nickel sensitization in females

The view generally held in the literature is that the frequent occurrence of concomitant nickel and cobalt sensitivity is due to simultaneous sensitization from suspenders, jewelry, etc. In a study population consisting of 168 unselected female twins representing a random sample of the general population, only a few were found with concomitant nickel and cobalt sensitivity, and then mainly among those with hand dermatitis. Similar concomitant cobalt and nickel was found only in dermatological female patients with hand dermatitis. The conclusion is t hat concomitant nickel and cobalt sensitization from metal alloys worn in direct contact with the skin is rare and that cobalt sensitization is probably a phenomenon secondary to an already existing and dermatitis.