Trends in Patch Testing of Black Patients: The Mayo Clinic Decade Experience (January 1, 2011, to December 31, 2020)

The purpose of this study was to review the results of patch testing in Black patients at Mayo Clinic over a decade. We retrospectively reviewed the results of patch testing to the standard, extended standard, or hairdresser series in 149 Black patients seen at Mayo Clinic (Rochester, MN; Scottsdale, AZ; and Jacksonville, FL) from January 1, 2011, to December 31, 2020. During the 10-year period, 149 Black patients (mean age, 49.2 years [SD, 17.1 years]; female 67.1%) were patch tested at Mayo Clinic to the standard, extended standard, or hairdresser series. Most common sites of dermatitis were generalized (30.9%), hands (18.8%), leg (16.8%), trunk (16.1%), and arm (14.8%). Overall, 109 patients (73.2%) had at least 1 positive reaction and 74 patients (50%) had 2 or more positive reactions. Overall, the 10 allergens with the highest reaction rates (from highest to lowest) identified in our study population were 4-amino-2-hyroxytoluene (33.3%), thimerosal (20.4%), nickel sulfate (18.9%), methylisothiazolinone (16.5%), methyldibromo glutaronitrile (13.4%), methyldibromo glutaronitrile/phenoxyethanol (12.5%), captan (12.5%), carmine (12.5%), methylchloroisothiazolinone/methylisothiazolinone (11.5%), and hydroperoxide of linalool 1% (11.3%). We describe patch test results in Black patients over a decade at Mayo Clinic. The top 10 allergens were preservatives, hair dyes, and fragrances. Differing patterns of allergens may occur in Black patients due to different patterns of exposures related to cultural practices.