Written on 22.04.2020. Posted in fragrance series.
How can allergenic fragrances be identified?
Testing if a fragrance has allergenic potential is a multi-stage process where each stage gets more expensive but also the evidence becomes stronger. Three principal methods that are applied one after another going from chemical analysis (also through computer simulations) via animal testing to clinical studies.
The ability of a chemical to react with and bind to proteins in the skin determines its potential to be a skin sensitizer. The relationship between molecular structure and protein reactivity forms the basis for identifying structural alerts by computer models. Computer-based methodology alone is not sufficient to identify allergens. But it can be used to make useful predictions.
Animal studies in mice or guinea pigs are used to provide information on the skin sensitizing potential and potency of fragrance substances. Based on this data fragrances are categorized as established contact allergens in animals.
Clinical studies are the definitive test to find out if a fragrance is an allergen. They are categorized by how many cases are reported. If less than 1000 persons have been tested, the data is not yet considered reliable. If more than 100 persons have reacted positively, a fragrance is classified as allergen of special concern. More about them in the next post.