No skin reactions to mineral powders in nickel-sensitive subjects.

Background: Cosmetic products are known to be able to induce contact dermatitis. Contact dermatitis may also be induced by nickel, and it is estimated that up to 17% of women are allergic to nickel.

Objectives: The aim of the present study was to investigate whether nickel sensitized individuals react to make-up products containing pigments with nickel as an impurity.

Patients/materials/methods: Twenty-three individuals with a clinical history of nickel allergy and/or with positive patch test reactions to nickel were exposed to mineral make-up products and individual pigments dispersed in alkylbenzoate (50%) in small Finn Chambers® for 48 hr. The skin reactions were evaluated visually and with a non-invasive instrument that quantifies skin erythema.

Results: The results showed that 74% of the included individuals showed a visible reaction to the positive control nickel sulfate, and a significant correlation was found between the visual and instrumental readings. However, none of the nickel sensitive individuals reacted to the test products. A subgroup analysis of the 50% most sensitive individuals also confirmed the absence of skin reactions to the powders.

Conclusions: The bioavailability of the trace amounts of nickel in the particles was below the level needed to elicit an eczematous reaction in any of the nickel-sensitized individuals.