Trends in Patch Testing With the Mayo Clinic Standard Series, 2017-2021.

Background: Patch testing to a standard series is used to identify culprit allergens in patients with contact dermatitis. The reaction rates evolve over time based on trends in cutaneous exposures by the general population. Objective: The aim of this study was to analyze the patch test results of the Mayo Clinic standard series in patients tested from 2017 to 2021. Methods: The patch test reactions of standard series allergens tested from 2017 to 2021 were retrospectively reviewed and compared with the results of our prior report from 2011 to 2015 as well as the North American Contact Dermatitis Group (NACDG) report from 2017 to 2018. Results: Of 2667 patients tested, 1683 (63.1%) had at least 1 positive reaction. The 15 allergens with the highest reaction rates were hydroperoxides of linalool 1%, nickel (II) sulfate hexahydrate, methylisothiazolinone, Myroxylon pereirae resin, hydroperoxides of linalool 0.5%, methyldibromo glutaronitrile, neomycin sulfate, cobalt (II) chloride hexahydrate, fragrance mix I, benzalkonium chloride, bacitracin, hydroperoxides of limonene, methylchloroisothiazolinone/methylisothiazolinone, p-phenylenediamine, and textile dye mix. Twelve (80%) of these allergens were also in the top 15 of the most recent NACDG report. Conclusions: Hydroperoxides of linalool and hydroperoxides of limonene are new allergens that have been added to our standard series. These are associated with high reaction rates.