What Is a Nickel Allergy?

A 2020 review in the journal Dermatitis says nickel remains the most commonly identified contact allergen, even though toxicology tests have typically indicated only a weak skin sensitization potential, and puts the proportion of the general population in Europe with nickel contact allergy at 14.5%. A 2023 review in Current Allergy and Asthma Reports says nickel is the most common allergen detected by patch testing in North America, with a positivity rate of 17.5% among patch-tested patients.

The 2023 review, which focused on occupational hand dermatitis, says a wide variety of occupations have been associated with nickel allergy, including hairdressers, cosmetologists, machine workers and healthcare workers, and that the most common sources of nickel were phones, machinery, tools and work wearables such as glasses, badges and clips. The NIOSH Pocket Guide lists sensitization dermatitis, allergic asthma and pneumonitis among the symptoms of workplace nickel exposure, identifies nickel as a potential occupational carcinogen, and lists a recommended exposure limit of 0.015 mg/m3 as a time-weighted average, with an OSHA permissible exposure limit of 1 mg/m3.

The European Union limits nickel release from items that touch skin. Under the REACH restriction as amended by Commission Regulation 552/2009, nickel may not be used in post assemblies inserted into pierced ears and other pierced body parts unless nickel release is less than 0.2 micrograms per square centimeter per week, or in articles intended for direct and prolonged skin contact, such as earrings, necklaces, bracelets, finger rings, watch cases and straps, and garment rivets, buttons and zippers, if release from the parts touching skin is greater than 0.5 micrograms per square centimeter per week.