Cobalt Allergy: While estimated to be rare, dermal exposure to cobalt - as with nickel sensitivity - can trigger dermatitis, asthma, and other allergic reactions, whereby pre-existing hypersensitivity to nickel is a risk factor for cobalt hypersensitivity or allergy. Home or work-related contact sources of cobalt are pottery, paints, some cosmetics, costume jewelry, antiperspirants, hair dyes, dental plates, etc., and also Vitamin B12 in the form of injections, as well as tablets. In addition to nickel and cobalt, chromium is another metal whose exposure may trigger an allergic reaction in some hypersensitive individuals, necessitating the use of gloves when handling any suspect metals, or applying a protective coat of varnish on items one has to touch and use... Full Text