Prevalence of reactive allergens in contact patch testing studies using the Brazilian standard battery: a systematic review

Background: Contact dermatitis is a common dermatosis in dermatology. The patch test is the gold standard for diagnosis, using a panel of common allergens and irritants. In Brazil, a standardized battery of 30 substances is used. However, comprehensive epidemiological data on contact dermatitis are limited, and no studies have compiled and compared nationwide results. Objectives: This study aimed to assess the positivity rate of patch tests using the Brazilian Standard Battery in suspected contact dermatitis cases from 2000 to 2022. We also evaluated associations between reactive substances and clinical and demographic variables and examined the variation in reactivity frequency to allergenic substances over the study period. Methods: A systematic literature review was conducted using PubMed, Scielo, and LILACS. We evaluated the prevalence of positive tests for each substance, examined associations between variables such as gender, region, and age, and assessed variations in patch test positivity over time. Results: Initially, 55 articles were identified, and 10 were included in the review. Nickel sulfate was the most frequently positive allergen, while triclosan, P-tertiary buthyphenol, and anthraquinone were the least prevalent. Test positivity increased every 5-years for kathon CG, neomycin, and nickel sulfate, while it decreased for quaternion 15 and thimerosal. Study limitations: The results were limited by the small number of articles included in the review. Conclusions: This pioneering study in Brazil provides valuable insights for dermatological allergy practitioners into the prevalence of patch test positivity for each substance in the Brazilian Standard Battery, aiding in informed decision-making and patient management. (c) 2025 Published by Elsevier Espana, S.L.U. on behalf of Sociedade Brasileira de Dermatologia. This is an open access article under the CC BY license (http://creativecommons.org/licenses/ by/4.0/).