Humans are exposed to a variety of metals on a daily basis, and nickel is the most frequent contact allergen. Currently little is known with regard to the frequency of sensitization to indium and iridium.
Study the prevalence of indium and iridium sensitization and evaluate the optimal patch test conditions.
364 patients were patch tested at the allergy unit of the University Hospital of Basel. Pure metals, metal chlorides and metal sulfates were applied in petrolatum or water in IQ test chambers for 2days and read twice at day (D) 2, and between D4 and D7.
Eleven patients reacted to indium salts (3.0%), 13 to iridium salts (3.6%), and one reacted to both salts. None of the patients reacted to pure metals. 19 of the 23 patients who reacted either to indium or iridium showed concomitant positive reactions to other metals, mainly nickel and palladium.
This retrospective clinical study provides insight into prevalence and test conditions of two rarely tested metal allergens in a larger patient cohort. A considerable number of indium or iridium positive subjects had co-sensitization to other metals. This article is protected by copyright. All rights reserved.

This article is protected by copyright. All rights reserved.