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.