Trends in Patch Test Results With the Mayo Clinic Extended Standard Series: A 14-Year Retrospective Review (2010–2023)

<u><b><i></i></b></u> <u><b><i>Background:</i></b></u> Extended patch testing beyond the standard series is commonly performed in patients with allergic contact dermatitis. This broader testing allows for more precise and complete allergen identification, ultimately leading to improved clinical outcomes. <u><b><i>Objective:</i></b></u> To report the Mayo Clinic Contact Dermatitis Group (MCCDG) patch testing results using a custom extended series from 2010 to 2023. <u><b><i>Methods:</i></b></u> A retrospective review of patch testing results using the MCCDG extended standard series at the Mayo Clinic was conducted. Data from 2010 to 2023 were analyzed. <u><b><i>Results:</i></b></u> Patch testing with the extended standard series was performed in 3,767 unique patients, with a total of 3834 extended standard patch tests administered (81.8% in women, 18.2% in men). The top 5 allergens eliciting positive reactions were gold (I) sodium thiosulfate (10.4%), benzisothiazolinone (10.4%), carmine (9.4%), thimerosal (9.3%), and hydroperoxides of linalool (8.8%). <u><b><i>Conclusions:</i></b></u> The extended standard series expands the diagnostic scope for patients in whom the standard series incompletely identifies relevant allergens. Preservatives and fragrances remain among the most common sensitizers, emphasizing the need for ongoing allergen surveillance, periodic review, and updates to patch test series to enhance diagnostic accuracy and patient care.