Contact Allergy to Metals

Nickel, chromium, and cobalt remain the most frequent causes of contact allergy in the general population, certain occupational groups, and dermatitis patients. Consumer products and occupational exposure are the main sources of sensitization and elicitation, whereas the role of medical and surgical implant is unclear. Pure metals, alloys, platings, and compounds have different ability to cause sensitization and dermatitis. Nickel release from certain items in contact with the skin and hexavalent chromium in cement and leather are limited by EU regulation for allergy prevention. Strong indications concerning reduced exposure and health benefits have been noted following the implementation of the regulations; however, the problems are still very large. The presence of cobalt in leather and the association with dermatitis among cobalt allergic patients is a new understanding. Several other metals are less frequent sensitizers, and some cause cross-reactivity. New data on cocktail effects and reactivity to nickel following short-term exposure have been published. Spot tests remain useful in the assessment of metal exposure and exposure reduction, but clearly better techniques are needed for most metals.