Preservatives are often added to cosmetic products to prevent growth of microorganisms, such as fungi or bacteria that may spoil the product or make the consumer ill.
Contact allergy to preservatives is well described in the literature and is one of the most frequent causes of contact allergy to cosmetic products.
The use of preservatives in cosmetic products is regulated by the EU through the Cosmetics Directive. Approval of a preservative requires, among other things, scientific evidence of the toxicological, mutagenetic and sensitizing potential. From these data, it will be decided in which concentration the preservatives may be used.
However, the approval do not inlude an evaluation of the presevative's antimicrobial efficacy. This means that there is a possibility that cosmetic products are "over-preserved". As the development of contact allergy i.a. is dependant on the concentration of the preservative in the product, too much preservation is likely to lead to more cases of contact allergy in consumers.
The purpose of this study is to define a maximum value for selected preservatives' efficacy towards microorganisms in cosmetic products. Based on the microbiological results a clinical study to investigate patients' allergic reactions to different concentrations of preservatives will be conducted.
In addition, the results will form the basis for developing a scientific guideline for determining the maximum permissible values of allergenic preservatives, which will include both efficacy and the risk of side effects. The overall purpose is that the incidence of allergy to preservatives decreases.
The research is carried out by MSc, PhD-fellow Michael Dyregaard Lundov from the National Allergy Research Centre.
