Patch Testing Results From the Massachusetts General Hospital Occupational and Contact Dermatitis Clinic, 2017-2022

Patch testing is gold standard for identifying the source of allergic contact dermatitis (ACD). To report patch testing results from the Massachusetts General Hospital (MGH) Occupational and Contact Dermatitis Clinic from 2017 to 2022. Retrospective analysis of patients referred to MGH for patch testing, 2017-2022. In total, 1438 patients were included. At least 1 positive patch test (PPT) reaction was observed in 1168 (81.2%) patients and at least 1 relevant PPT reaction was observed in 1087 (75.6%) patients. The most common allergen with a PPT was nickel (21.5%), followed by hydroperoxides of linalool (20.4%) and balsam of Peru (11.5%). Sensitization rates statistically increased over time for propylene glycol and decreased for 12 other allergens (all P values <0.0004). Retrospective design, single institution tertiary referral population, and variations in allergens and suppliers across the study period. The field of ACD is constantly evolving. Regular analysis of patch test data is crucial to identify emerging and diminishing contact allergen trends.