Developing a cosmetic series: Results from the ESSCA network, 2009-2018

Legislation and Current Practices Concerning Risk Assessment of Skin Sensitizers in the European Union: A Comparative and Survey Study

BACKGROUND

Despite legislation aimed to protect the population against skin sensitization in the European Union (EU), over one quarter of the general population is sensitised to at least one chemical.

OBJECTIVES

To provide an overview and comparison of European legislation concerning skin sensitization. In addition, we gathered the opinions of experts and stakeholders regarding improvements in the legislation and risk assessment process in the EU, to provide suggestions for improvement.

METHODS

Legislation was identified and compared. Four questionnaires were created towards industry, competent authorities and regulators, researchers/clinicians, and non-governmental organisations. The questions concerned the legislation, the risk assessment process, data collection and potential improvements.

RESULTS

Seven areas of legislation were analysed. The legislation was found to be unharmonised, for example, differing modes of restriction and accepted tests for skin sensitization. Approximately 40% of the questionnaire respondents found that the EU legislation and tools were not sufficiently protective. To improve the legislation 83% suggested harmonisation and 68% suggested better data sharing. Other areas were: improved exposure data (78%), better understanding of the skin sensitization mechanism (67%) and non-animal tests (66%).

CONCLUSIONS

Stakeholders had varying confidence towards the protection of European citizens against skin sensitization. Multiple areas for improvement regarding the legislations and the risk assessment process were identified.

Toluene-2,5-Diamine Sulfate: Allergen of the Year 2025

Toluene-2,5-diamine sulfate (PTDS), also known as toluene diamine sulfate or 2,5-diaminotoluene sulfate, is an aromatic amine that can be used as a paraphenylenediamine (PPD) hair dye alternative. Patients may develop contact allergy to PTDS, and it is often omitted from standard patch test screening series, possibly leading to underdiagnosis. The American Contact Dermatitis Society named PTDS the Allergen of the Year for 2025, aiming to raise awareness of its dual role as both an allergen and an alternative for some PPD-allergic individuals.

A Soothing Lavender-Scented Electrospun Fibrous Eye Mask

Electrospinning technology has demonstrated extensive applications in biomedical engineering, energy storage, and environmental remediation. However, its utilization in the cosmetic industry remains relatively underexplored. To address the challenges associated with skin damage caused by preservatives and thickeners used for extending the shelf life of conventional products, a soothing lavender-scented electrospun fibrous eye mask with coaxial layers was developed using the electrospinning technique. Polyvinyl alcohol (PVA) served as the hydrophilic outer sheath, while polycaprolactone (PCL) constituted the hydrophobic core, with lavender oil (LO) encapsulated within. The structural and physicochemical properties of the samples were characterized using a scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and contact angle measurements. Upon hydration, the fibrous membrane exhibited strong adhesion properties, notable antioxidant activity, and a degree of antibacterial efficacy, demonstrating its potential for safe and effective use in skincare and eye mask applications. These findings suggest that the developed electrospun material offers promising functional properties and functional properties for integration into cosmetic formulations.

Deciphering trends in replacing preservatives in cosmetics intended for infants and sensitive population

The present study aims to investigate the current trends in replacing conventional preservatives with multifunctional ingredients with antimicrobial properties for preservation of cosmetics for infants or sensitive population, to decrease their potential for contact dermatitis. We first reviewed the labels of cosmetics purchased from the Chinese market for conventional preservatives and multifunctional ingredients with antimicrobial properties, of which the actual contents were further quantified by chromatographic methods. We identified 7 traditional preservatives (phenoxyethanol, benzoic acid (salts), methylparaben, benzyl alcohol, sorbic acid (salts), propylparaben, and methylisothiazolinone), and 11 alternative ingredients with antimicrobial activities (ethylhexylglycerin, butylene glycol, caprylyl glycol, propylene glycol, 1,2-hexanediol, p-anisic acid, hydroxyacetophenone, pentylene glycol, decylene glycol, caprylhydroxamic acid, and aminomethyl propanol) in descending order of prevalence. The contents of all identified preservatives and ingredients were either below regulatory limits or in the range that is generally regarded to be safe. Further challenge with microorganisms indicated irrespective of the composition of preservation systems, product preservation could be compromised under test conditions. We conclude that multifunctional ingredients with antimicrobial properties in cosmetics have the potential to completely replace or significantly reduce the use of traditional preservatives while retaining comparative preservative efficacy. Future attentions may need to be shifted to the safety of those multifunctional ingredients with antimicrobial properties.

Supplemental Patch Testing Identifies Allergens Missed by Standard Screening Series

Background: Supplemental patch testing is an adjunct to standard patch test screening series. Objective: To determine the demographics, characteristics, frequency, relevance, and interpretation of patch test reactions for supplemental patch testing. Methods: Retrospective study of patients tested 2017-2020 with North American Contact Dermatitis Group (NACDG) and supplemental screening series (Supplemental Series A [SSA], Supplemental Series B [SSB]). Demographics, characteristics, reaction strengths, relevance, and final interpretation were recorded. Results: Cohort included 791 patients; 73.5% female, 68.6% age >40 years. 74.1% were White, 15.2% Black, 5.7% Asian, and 1.5% Hispanic. The most common Dermatitis sites were scattered/generalized (27.2%), face (24.0%), and hands (23.5%). For 2017-2018 and 2019-2020, respectively, 82% (318/388) and 78.4% (316/403) had ≥1 "allergic" reaction. In addition, 13.5% (52/385) and 11.7% (47/403) had SSA reactions, and 38.1% (115/302) and 31.5% (101/321) had SSB reactions. In the 87 (2017-2018) and 99 (2019-2020) patients with negative NACDG testing, 17 (19.5%) and 12 (12.1%) had supplemental reactions. Of the 34 supplemental allergens with reaction frequency ≥1%, 58.8% (20/34) are not part of the American Contact Dermatitis Society 90 (2020) or NACDG 2021-2022 screening series. The highest frequency allergens from this group were dodecyl and octyl gallate, cinnamic alcohol, phenyl salicylate, hexahydro-1,3,5-tris-(2-hydroxyethyl) triazine, and abitol. Conclusions: Supplemental patch testing identifies additional relevant allergens in patients with suspected allergic contact Dermatitis.

Artificial Intelligence That Predicts Sensitizing Potential of Cosmetic Ingredients with Accuracy Comparable to Animal and In Vitro Tests-How Does the Infotechnomics Compare to Other "Omics" in the Cosmetics Safety Assessment?

The aim of the current study was to develop an in silico model to predict the sensitizing potential of cosmetic ingredients based on their physicochemical characteristics and to compare the predictions with historical animal data and results from "omics"-based in vitro studies. An in silico model was developed with the use of WEKA machine learning software fed with physicochemical and structural descriptors of haptens and trained with data from published epidemiological studies compiled into estimated odds ratio (eOR) and estimated attributable risk (eAR) indices. The outcome classification was compared to the results of animal studies and in vitro tests. Of all the models tested, the best results were obtained for the Naive Bayes classifier trained with 24 physicochemical descriptors and eAR, which yielded an accuracy of 86%, sensitivity of 80%, and specificity of 90%. This model was subsequently used to predict the sensitizing potential of 15 emerging and less-studied haptens, of which 7 were classified as sensitizers: cyclamen aldehyde, N,N-dimethylacrylamide, dimethylthiocarbamyl benzothiazole sulphide, geraniol hydroperoxide, isobornyl acrylate, neral, and prenyl caffeate. The best-performing model (NaiveBayes eAR, 24 parameters), along with an alternative model based on eOR (Random Comittee eOR, 17 parameters), are available for further tests by interested readers. In conclusion, the proposed infotechnomics approach allows for a prediction of the sensitizing potential of cosmetic ingredients (and possibly also other haptens) with accuracy comparable to historical animal tests and in vitro tests used nowadays. In silico models consume little resources, are free of ethical concerns, and can provide results for multiple chemicals almost instantly; therefore, the proposed approach seems useful in the safety assessment of cosmetics.

The European baseline series and recommended additions: 2023

The European baseline series was last updated in 2019. This article discusses the reasoning behind a further iteration of the series for 2023.

Seven cases of contact dermatitis due to stearyl alcohol contained in topical medications

Stearyl alcohol is found in various cosmetics and topical medications and is regarded as safe. Allergic contact dermatitis is reported due to this chemical on rare occasions. We report seven cases, comprising three men and four women aged between 36 and 62 between the years 2013 to 2019, of allergic contact dermatitis due to the use of topical medication, where the patient showed a positive result to a patch test using stearyl alcohol. There were 10 topical medications that we considered to be the cause of this: three were from Oronine^® H ointment, two from Eurax^® cream, one from Eurax H cream, and four from topical antifungal medications. All these medications contained stearyl alcohol. Seven cases of patch tests with stearyl alcohol all showed positive results. Moreover, having done a patch test with cetyl alcohol, two out of three tests showed positive. When researching allergic contact dermatitis due to topical medications, it is important to test for allergy to stearyl alcohol as well as their main ingredients, because it is contained in numerous products and has the ability to cause allergic contact dermatitis.

Facial contact dermatitis caused by cosmetic-relevant allergens

BACKGROUND

Facial allergic contact dermatitis caused by cosmetic products is common. New allergens in cosmetics continuously emerge.

OBJECTIVES

To investigate characteristics of patients with facial dermatitis (FD) between 2010 and 2019 including patch test results from cosmetic-related allergens and a new test series with cosmetic-relevant natural ingredients (CRNIs).

METHODS

This is a retrospective study analysing demographics, clinical characteristics according to MOAHLFA index (male; occupation; atopic dermatitis; hand; leg; face; age ≥ 40 years), and patch test results to 27 cosmetic-relevant allergens in FD patients. A prospective study evaluating a screening test series with CRNIs in consecutive FD patients for 1 year was also conducted. These patients received a questionnaire for collecting extra characteristics (eg, concerning quality of life).

RESULTS

Of 8740 tested patients, 2292 (26.2%) had FD. Of these, 30.6% had cosmetic-induced FD. The most common cosmetic-related allergens were fragrances and preservatives. The most common patch test-positive CRNIs were hydroperoxides of limonene and linalool, and propolis. Potato and peanut were rare, but the most common prick test-positive CRNIs, however, without any relation to the use of cosmetic products. FD affected nearly all patients' quality of life and caused limitations to their daily life.

CONCLUSIONS

Updated management and quick diagnosis of FD is important to avoid negative impact on patients' quality of life.

Allergic contact dermatitis from potassium sorbate and sorbic acid in topical pharmaceuticals and medical devices

BACKGROUND

The preservatives sorbic acid (SA) and potassium sorbate (PS) are considered rare skin sensitizers. PS-containing products always contain SA to a certain extent, and positivity to PS may reflect sensitization to SA. Their optimal patch-test conditions are unknown.

OBJECTIVES

To report on the outcome of testing with SA and PS in various concentrations and/or vehicles.

PATIENTS AND METHODS

Seventeen patients with allergic contact dermatitis from PS/SA-containing topical pharmaceuticals and medical devices were patch tested to SA 2% and 5% pet.; SA 1%, 2%, 3%, 5%. eth.; and/or SA 2% aq., whereas PS was patch tested 5% pet. and/or 5% aq.

RESULTS

Only one patient, not tested to the ethanol preparations, presented with a (doubtful) positive reaction to SA 2% pet., while this remained negative in 13 patients who reacted to SA 2% eth. The preparations containing SA 5% pet.; 1%, 3%, and 5% eth.; and SA 2% aq. had little or no additional value. PS 5% pet. performed better than 5% aq., and always mirrored SA sensitization.

CONCLUSIONS

Sensitization to SA and PS is probably underestimated. SA 2% eth. and PS 5% pet. are preferred for patch testing, and patients sensitized to SA should avoid PS-containing products.

HIGHLIGHTS

Potassium sorbate (PS) and sorbic acid (SA) are widely used preservatives. PS-containing products always contain some SA. Both are considered rare skin sensitizers, but contact allergy in response to them might be underestimated. SA 2% eth. and PS 5% pet., rather than SA 2% pet. and PS 5% aq., respectively, may be required to diagnose contact allergy from PS/SA-containing topical pharmaceuticals and medical devices. A positive patch test to PS reflects sensitization to SA, and patients sensitized to SA should also avoid PS-containing products.