We found that overall 0.7% of patients were positive to this allergen with a relevance rate of 45%. However, internationally positivity rates are decreasing; falling from 0.78% from 1980 to 2009 to just 0.03% from 2010 to 2018 at a tertiary patch test centre in the United Kingdom. 9 We found 31 positive and eleven relevant reactions to dodecyl gallate. Dodecyl gallate, the ester of dodecanol and gallic acid, is an antioxidant and preservative in foods and cosmetics. In our patients, reactions were caused by cosmetics, handling cooking oils and margarine and ingested food. Gallates are often excluded from baseline series because of difficulty ascertaining relevance. However, gallate reactions may be rising and our results suggest that ongoing surveillance is needed and future consideration of inclusion in the ABS if local data confirm increased positivity and relevance rates. 10 Several ABS allergens are not included in our local baseline series. This is a limitation of our study as they were not tested in consecutive patients as the local standard series used over the study period differ from the ABS. For example, methylisothiazolinone was positive in 13.5% of patients tested, but only 1.3% of all patients presenting for patch testing overall because only 155 patients were tested to MI.In conclusion, we report the performance of ABS allergens in detecting positive and relevant reactions in a population undergoing patch testing in Sydney. The ABS detected 72.9% of relevant reactions. Missed allergens included fragrances and dodecyl gallate. The two clinics at Darlinghurst and Westmead have since adopted the ABS and unified their supplementary allergen series.

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