Quantitative Risk Assessment (QRA) for Dermal Sensitization
Based on REXPAN’s recommendation, IFRA and RIFM have formally agreed to adopt the Quantitative Risk Assessment (QRA) approach, refined for fragrance ingredients identified as contact allergens, as the core strategy for primary prevention of dermal sensitization to these materials in consumer products.
The QRA methodology for dermal sensitization for fragrance ingredients identifies concentration limits for various of product types. These product types are grouped into product categories according to similar safety assessment factors and exposure, which lead to similar acceptable use levels of a fragrance ingredient. As such, the QRA is a step forward on existing risk management strategies, under which each specific fragrance ingredient identified as an allergen is limited to the same concentration across all skin-contact product types.
Skin exposure in terms of dose per unit area is highly important for the quantitative risk assessment methodology. Some of the chemicals in common use today may have the potential to cause dermal sensitization. However, the fact that a chemical is a dermal sensitizer does not mean it cannot be formulated into consumer products at safe levels. This is also the case for fragrance ingredients.
Based on the chemical, cellular and molecular understanding of dermal sensitization, it is possible to conduct an exposure-based QRA to determine safe levels of fragrance ingredients in different consumer product types. The implementation of the Dermal Sensitization QRA approach started in May 2006, with the publication of a first set of QRA Standards as part of the 40th Amendment.