Purpose of review: Preservatives are well known skin sensitizers and represent one of the main causes of contact allergy. The purpose of this article is to review the current state of contact sensitization induced by preservatives and point future alternatives for products' preservation.
Recent findings: Isothiazolinones currently are the most common preservatives responsible of contact allergy in Europe and in the United States, and although some regulatory interventions have been taken place, the current contact allergy outbreak is not yet under control. Despite the ban of methyldibromo glutaronitrile from cosmetics in Europe, sensitized patients are still diagnosed, suggesting other nonregulated sources of exposure. Sensitization rates to formaldehyde and formaldehyde-releasers are lower in Europe in comparison with the United States due to stricter regulations regarding their use. Prevalence of contact allergy to parabens has remained stable over the last decades, whereas iodopropynyl butylcarbamate is an emerging allergen with an increasing prevalence. Future alternatives for products' preservation look for a broad antimicrobial spectrum, but with a better safety profile (in terms of sensitization) than the currently available compounds.
Summary: Given the high rates of sensitization reported over the last years, timely regulatory actions are urgently required for some preservatives that currently represent a concern for public health.