Trends in Contact Allergy to Preservatives From 2014 to 2023: Benzisothiazolinone on the Rise

BackgroundSkin sensitising preservatives are commonly used in consumer and industrial products. The widespread use of preservatives has led to recurrent epidemics of contact allergy.

ObjectivesTo investigate temporal trends of contact allergy to preservatives from 2014 to 2023. MATERIALS AND METHODS: Patients consecutively patch tested with preservatives from the European baseline series and the supplementary baseline series at Gentofte hospital from 2014 to 2023 were included.

ResultsThe study population included 6435 patients. Contact allergy to benzisothiazolinone (BIT) increased significantly from ≤ 0.3% in 2014 to 5.0% in 2023. Painters and machine operators, and assemblers were most often sensitised to BIT, and detergents and paints were the most common exposures to BIT. Contact allergy to methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) decreased significantly from 3.3% in 2014 to 2.2% in 2023. Likewise, contact allergy to MI declined significantly from 3.9% in 2014 to 2.5% in 2023. Stable trends were found for the overall prevalence of contact allergy to preservatives from 9.0% in 2014 to 10.2% in 2023.

ConclusionsRegulatory restrictions on the use of MI and MCI/MI in cosmetic products have led to a decrease in contact allergy. However, the rise in contact allergy to BIT underscores the need for ongoing monitoring and preventive measures.