Allergic contact dermatitis in preservatives: current standing and future options

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.

The influence of Leucidal, a natural cosmetic preservative, on fibroblast and keratinocytes. Studies on cells and on model membrane systems

The aim of this work was to investigate the influence of Leucidal® Liquid (abbr. Leucidal), which is recommended as a natural cosmetic ingredient of antimicrobial properties, on model membranes of keratinocytes and fibroblasts. The toxicity tests on cell lines were also performed to allow for a more detailed discussion of the results. As model membrane systems the lipid Langmuir monolayers were applied. During the investigations, the surface pressure/area measurements, penetration studies and Brewster Angle Microscopy (BAM) visualization were performed for one component and mixed lipid monolayers. It was evidenced that at the membrane - corresponding conditions, the components of Leucidal do not penetrate either model keratinocyte and fibroblast membranes or one component films composed of the major lipids of skin cell membranes. Leucidal makes these systems slightly more expanded and less stable, however this is not reflected in the changes in the film morphology. Only the ceramide systems were sensitive to the presence of Leucidal, i.e. the incorporation of Leucidal components manifested well in the decrease of the films' condensation and alterations in their morphology. The tests on cells demonstrated that Leucidal is non toxic for these types of cells at the concentrations suggested by the producer. A thorough comparison of these results with those published for bacteria model membranes enabled us to discuss them in the context of the mechanism of action of Leucidal components. It was concluded that Leucidal components are of low affinity to the skin cellular model membranes of low content of Leucidal-sensitive ceramides and are not toxic for fibroblast and keratinocyte cell lines. Moreover, the lipid composition of the membrane and its molecular organization can be important targets for Leucidal components, decisive from the point of view of the activity and selectivity of the studied composition.

Analysis of preservatives and fragrances in topical medical devices: The need for more stringent regulation

INTRODUCTION

Medical devices (MDs) have a long history of use, and come with regulatory frameworks to ensure user safety. Although topically applied MDs in the form of gels and creams might be used on damaged skin, their composition is often similar to that of cosmetic products applicable to intact skin, especially in terms of preservatives and fragrances. However, unlike cosmetics, these products are not subject to compound-specific restrictions when used in MDs.

OBJECTIVE

This study aimed to identify and quantify preservatives and fragrances in topically applied MDs and assess their safety towards the Cosmetic Regulation (EC) 1223/2009.

METHOD

Sixty-nine MDs available on the EU market were subjected to previously validated liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) methods to identify and quantify occurring preservatives and fragrances.

RESULTS

Findings revealed that 32% of the examined MDs did not provide comprehensive ingredient lists, leaving users uninformed about potential risks associated with product use. Furthermore, 30% of these MDs would not meet safety standards for cosmetic products and, most significantly, 13% of the analysed samples contained ingredients that are prohibited in leave-on cosmetics.

CONCLUSION

Results highlight the pressing demand for more stringent requirements regarding the labelling and composition of MDs to enhance patient safety. Improved regulation and transparency can mitigate potential risks associated with the use of topically applied MDs.

Trends in contact sensitization, results, and implications from a contact dermatitis clinic in Israel

BACKGROUND

The baseline series includes common allergens, evolves over time, and differs by location. Our study aims to characterize allergen sensitization trends among the Israeli population during the last two decades, compare our results to American and European registries, as well as to highlight significant allergens in additional series outside the European baseline series (OEBS).

METHODS

We analysed patch test results of 2086 patients from a designated contact dermatitis clinic in Tel Aviv between 2019 and 2022, compared them to European and North American registries and to 2156 patch test results conducted in Israel two decades ago.

RESULTS

38.6% of patients had at least one positive reaction to an allergen in the European baseline series (EBS), nickel sulphate (14.6%), fragrance mix I (4.6%), and Methylchloroisothiazolinone methylisothiazolinone (MCI/MI; 3.7%) were the most common among them. N-Isopropyl N-Phenyl-4-Phenylenediamine (NIPPD; 0%), Propolis (0.1%), Sesquiterpene lactone mix (0.1%), and Budesonide (0.1%) elicited a sensitization frequency significantly lower than the proposed threshold for baseline inclusion. Chi-square test revealed a statistically significant decrease (p < 0.05) in the sensitization frequency of fragrance mix I, Formaldehyde, Potassium dichromate, Neomycin sulphate, Myroxylon pereirae, Sesquiterpene lactone, and NIPPD during the last two decades. The overall sensitization frequency to the majority of allergens was lower in our cohort in comparison to the North American and European registries.

CONCLUSIONS

MCI/MI and 2-hydroxyethyl methacrylate-2 (HEMA) are common, relevant allergens, with high SPIN (significance and prevalence index number) and should be better regulated by the authorities. While among the EBS, NIPPD, Propolis, Sesquiterpene lactone, and Budesonide usually do not elicit a positive reaction and therefore should be reconsidered in baseline series, among the OEBS, Chloramphenicol, Quaternium 15, Propyl gallate, and Amerchol L101 have elicited high SPIN values and should be vigilantly examined in the suitable clinical scenario. Significantly lower sensitization frequency to propolis raises the possibility of a protective effect due to early oral exposure among the Israeli population.

Patch Test Results Among Older Adults: A Retrospective Analysis of the North American Contact Dermatitis® Group Data (2009-2020)

Background: Allergic contact Dermatitis® (ACD) in older adults (OA) represents a significant health burden, but few studies examine the prevalence and characteristics of contact allergy and ACD in this population. Objective: To compare positive and clinically relevant patch test results in OA versus younger adults (YA) and children. Methods: Retrospective analysis of patch test results obtained in OA (≥65 years), YA (19-64 years), and children (≤18 years) by the North American Contact Dermatitis® Group, 2009 to 2020. Results: Of 28,177 patients patch tested, 5366 (19.0%) were OA. OA were more likely to have a final primary diagnosis of ACD as compared with YA (50.8% vs 49.2%, P = 0.035) and children (44.6%, P < 0.0001). The primary site of Dermatitis® also differed by age group, with OA having a higher proportion of Dermatitis® affecting the trunk, scalp, anogenital region, and "under clothing," and a lower proportion of Dermatitis® affecting the face, lips, and feet. Limitations: Retrospective design, lack of follow-up, and referral population. Conclusion: OA were as likely and were statistically even more likely to have a final primary diagnosis of ACD compared with YA and children. Anatomic site of Dermatitis® also differed by age group. This underscores the need for patch testing in OA when ACD is suspected.

Antimicrobial, Preservative, and Hazard Assessments from Eight Chemical Classes

Preservatives, such as isothiazolinones and formaldehyde-releasing compounds, provide safety and stability in consumer products by preventing microbial contamination. Yet these ingredients present human and environmental hazards, including allergic contact dermatitis and aquatic toxicity. The development of safer alternatives has been stymied by trade-offs between safety and efficacy. To enable the identification of safer preservatives, substances from eight functional classes were assessed for antimicrobial efficacy and human and environmental hazards. First, 130 substances were evaluated for microbial inhibitory activity against two relevant model microorganisms, Aspergillus brasiliensis (filamentous fungi) and Pseudomonas aeruginosa (Gram-negative bacteria). High-performing compounds within each class were assessed for hazards across a broad suite of human and environmental health end points. Four promising compounds were selected for further testing based on microbial inhibition, hazard profiles, and commercial availability. These ingredients were tested for biocidal activity in model home care formulations using methods adapted from industrial preservative challenge guidelines (USP-51). Two substances were identified, caprylhydroxamic acid and caprylyl glycol, that provided adequate preservation and improved toxicity profiles compared to isothiazolinone and formaldehyde-releasing preservatives. This study highlights trade-offs between antimicrobial activity and hazards across a broad spectrum of chemical classes relevant to safer preservative development.

Increased rates of contact allergy to selected preservatives in patients with allergic contact dermatitis in Turkey

BACKGROUND

Preservatives are a frequent cause of allergic contact dermatitis (ACD) and have caused numerous epidemics.

OBJECTIVES

The objective of this study is to determine the prevalence of preservative sensitivity, assess the change in the frequency of sensitivity, identify new preservatives with increased sensitivity rates, and evaluate the situation in Turkey by comparing our findings with current literature.

METHODS

A total of 201 patients diagnosed with ACD between 2018 and 2020, were patch tested with the European baseline series and additional seven preservative haptens. The change in the prevalence of sensitivity to each preservative hapten was investigated by comparing the data from the study conducted in our department between 2000 and 2004.

RESULTS

Results showed that 17.4% (n = 35) of the patients were positive to preservatives. Comparison with previous data from 2000 to 2004 revealed an increase in the frequency of sensitization. The most prevalent allergen was methyldibromo glutaronitrile (9.5%), followed by methylchloroisothiazolinone/methylisothiazolinone (6.5%), and methylisothiazolinone (5%).

CONCLUSION

The increase in preservative sensitivity in Turkey is the most remarkable finding. Although MDBGN was prohibited in cosmetic products, MCI/MI and MI are still widely used. Our findings suggest that awareness of preservative sensitivity should be increased and additional precautions should be taken, also in Turkey, regarding the use of preservatives.

The influence of Leucidal - eco-preservative from radish - on model lipid membranes and selected pathogenic bacteria

In this work the effect of Leucidal - a natural preservative from radish dedicated to be used in cosmetics - on bacteria cells and model bacteria membranes was investigated. To get insight into the mechanism of action of this formulation the lipid Langmuir monolayers imitating Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) membranes were prepared. Then, the influence of Leucidal on model systems was investigated by means of the surface pressure/area measurements, penetration studies and Brewster Angle Microscopy (BAM) visualization. Similar experiments were done also for one component monolayers formed from the model membrane lipids. The in vitro tests were done on five different bacteria species (E. coli, Enterococcus faecalis, S. aureus, Salmonella enterica, Pseudomonas aeruginosa). Leucidal was found to decrease packing of the monolayers, however, it was excluded from the films at higher concentrations. Model membrane experiments evidenced also a stronger affinity of the components of this eco-preservative to E. coli vs S. aureus membrane. Among one component films, those formed from phosphatidylglycerols and cardiolipins were more sensitive to the presence of Leucidal. However, in vitro tests evidenced that Leucidal exerts stronger inhibitory effect against S. aureus bacteria as compared to E. coli strain. These findings were discussed from the point of view of the role of Leucidal components and the lipid membrane properties in the membrane - based mechanism of action of this preservative. The results allow one to suggest that the membrane may not be the main site of action of Leucidal on bacteria. Moreover, since high concentration of the tested preparation exerted antibacterial activity in relation to all tested bacteria, a low selectivity of Leucidal can be postulated, which may be problematic from the point of view of its effect on the skin microbiome.

Immune mechanisms in vulvodynia: key roles for mast cells and fibroblasts

Vulvodynia is a debilitating condition characterized by painful sensitivity to touch and pressure in the vestibular tissue surrounding the vaginal opening. It is often a "diagnosis of exclusion" of idiopathic pain made in the absence of visible inflammation or injury. However, the association between increased vulvodynia risk and a history of yeast infections and skin allergies has led researchers to explore whether immune mechanisms of dysregulated inflammation might underlie the pathophysiology of this chronic pain condition. Here we synthesize epidemiological investigations, clinical biopsies and primary cell culture studies, and mechanistic insights from several pre-clinical models of vulvar pain. Taken together, these findings suggest that altered inflammatory responses of tissue fibroblasts, and other immune changes in the genital tissues, potentially driven by the accumulation of mast cells may be key to the development of chronic vulvar pain. The association of increased numbers and function of mast cells with a wide variety of chronic pain conditions lends credence to their involvement in vulvodynia pathology and underscores their potential as an immune biomarker for chronic pain. Alongside mast cells, neutrophils, macrophages, and numerous inflammatory cytokines and mediators are associated with chronic pain suggesting immune-targeted approaches including the therapeutic administration of endogenous anti-inflammatory compounds could provide much needed new ways to treat, manage, and control the growing global pandemic of chronic pain.

A systematic review of allergic and irritant contact dermatitis of the vulva: The most important allergens/irritants and the role of patch testing

Vulvar allergic contact dermatitis (vACD) and irritant contact dermatitis (vICD) are common and accompanied by a great burden on the patient's life. We aimed to review the existing literature on vACD and vICD in order to provide a comprehensive reference list of potential vulvar allergens and irritants, as well as to establish the role of patch testing therein. A systematic search was performed in Medline, Embase and Web of Science using a search string based on the PICO-format. The study protocol was registered at PROSPERO (CRD42021239527). Multiple allergens were identified and included metals, topical drugs, fragrances, preservatives, cosmetic constituents and rubber components. Not all positive reactions were, however, considered to be relevant. Patch testing is the primary tool for the identification of the causal allergens. Testing with standard series alone was proven to be insufficient. Little information about irritants was found. In the future, additional series and late readings should be considered in standard practice. Studies on vICD are scarce and further research is necessary. More population-based research should be performed.

Preservatives in non-cosmetic products: Increasing human exposure requires action for protection of health

The widespread use of skin sensitizing preservatives is well-known. Contact allergy to preservatives is often caused by their presence in cosmetic products. Preservative use in non-cosmetic products is less well-known. We have reviewed European Union (EU) legislations on classification and labelling, biocides and cosmetics, concerning conditions for use of the most used sensitizing preservatives (including formaldehyde-releasing substances, isothiazolinones and parabens). We have analysed temporal trends in their use in non-cosmetic products (tonnes, number of products, concentrations), based on annual reports to the Swedish Products Register 1995-2018; and we discuss implications for stakeholders. Major changes over time are that the use of most of the preservatives has increased by tonnes and/or by number of products, and that several use concentrations have declined following harmonized classification as a skin sensitizer with low concentration limits for this classification. We conclude that the massive increase in use of preservatives is alarming, and that urgent action is needed for protection of health. Their use in non-cosmetic products is broad, increasing and often undisclosed. In the EU, legislations concerning chemicals can provide relevant restrictions to reduce their use and associated health risks, monitored by efficient surveillance. Prevention would be benefited by better coordination between legislations.

Decision making in next generation risk assessment for skin allergy: Using historical clinical experience to benchmark risk

Our aim is to develop and apply next generation approaches to skin allergy risk assessment that do not require new animal test data and better quantify uncertainties. Quantitative risk assessment for skin sensitisation uses safety assessment factors to extrapolate from the point-of-departure to an acceptable human exposure level. It is currently unclear whether these safety assessment factors are appropriate when using non-animal test data to derive a point-of departure. Our skin allergy risk assessment model Defined Approach uses Bayesian statistics to infer a human-relevant metric of sensitiser potency with explicit quantification of uncertainty, using any combination of human repeat insult patch test, local lymph node assay, direct peptide reactivity assay, KeratinoSens™, h-CLAT or U-SENS™ data. Here we describe the incorporation of benchmark exposures pertaining to use of consumer products with clinical data supporting a high/low risk categorisation for skin sensitisation. Margins-of-exposure (potency estimate to consumer exposure level ratio) are regressed against the benchmark risk classifications, enabling derivation of a risk metric defined as the probability that an exposure is low risk. This approach circumvents the use of safety assessment factors and provides a simple and transparent mechanism whereby clinical experience can directly feed-back into risk assessment decisions.

Patch test results with the European baseline series, 2019/20-Joint European results of the ESSCA and the EBS working groups of the ESCD, and the GEIDAC

BACKGROUND

Continual analyses of patch test results with the European baseline series (EBS) serve both contact allergy surveillance and auditing the value of included allergens.

OBJECTIVES

To present results of current EBS patch testing, obtained in 53 departments in 13 European countries during 2019 and 2020.

METHODS

Anonymised or pseudonymised individual data and partly aggregated data on demographic/clinical characteristics and patch test rest results with the EBS were prospectively collected and centrally pooled and analysed.

RESULTS

In 2019 and 2020, 22 581 patients were patch tested with the EBS. Sensitization to nickel remained most common (19.8 [19.2-20.4]% positivity [95% confidence interval]). Fragrance mix I and Myroxylon pereirae yielded very similar results with 6.80 (6.43-7.19)% and 6.62 (6.25-7.00)% positivity, respectively. Formaldehyde at 2% aq. yielded almost one percentage point more positive reactions than 1% concentration (2.49 [2.16-2.85]% vs. 1.59 [1.33-1.88]); methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and MI alone up to around 5% positives. Among the new additions, propolis was most commonly positive (3.48 [3.16-3.82]%), followed by 2-hydroxyethyl methacrylate (2.32 [2.0-2.68]%).

CONCLUSION

Ongoing surveillance on the prevalence of contact sensitization contributes to an up-to-date baseline series containing the most frequent and/or relevant contact sensitizers for routine patch testing in Europe.

Sustainable changes in beauty market trends focused on the perspective of safety in the post-coronavirus disease-19 period

BACKGROUND

In February 2020, WHO announced the outbreak of coronavirus disease-19 (COVID-19) in a global epidemic, and the COVID-19 vaccine has recently been developed and approved in many countries to release disease radio waves. Immediately distributed and used to control and control infections. During the COVID-19 pandemic, the world closed extensively in beauty and beauty services to control the spread of the virus.

OBJECTIVES

Therefore, this study for the first time that the perspective of safety in sustainable may be applied to the entire alteration of beauty industry market in the post-COVID-19 pandemic for literature review.

METHODS

A Narrative Review is proposed as a new report and commentary on the sustainable change of beauty market trends centered on safety due to the COVID-19 pandemic in December 2020. It was written with reference to keywords such as "Covid Beauty Market," "Covid Sustainable," "Covid clean beauty," and "Safety beauty." This study was performed by searching on PubMed, Google Scholar, Scopus, and ResearchGate. A total of 383 papers were retrieved, of which 36 were successfully included in this study.

RESULTS

Analysis of customers and markets in the beauty industry since COVID-19 was absolutely required at this time. Harmful and safe edible ingredients of clean beauty perspective should be compared and analyzed. In addition, importance of sustainability value from a clean beauty perspective should be considered.

CONCLUSION

There is an era in which the perspective of safety in sustainable may be applied to the entire beauty industry today. In addition, depending on the customer's perception change, beyond the ingredients, raw material procurement of products, manufacturing process, product experiments, etc. are part of clean beauty to minimize carbon emissions, water use, recycle product containers, and reduce waste.

Contact allergy to and allergic contact dermatitis from formaldehyde and -releasers: A clinical review and update

This review aims to provide a clinically useful update regarding the role of formaldehyde (FA) and its five main releasers (FRs) quaternium-15, diazolidinyl urea, DMDM hydantoin, imidazolidinyl urea and 2-bromo-2-nitropropane-1,3-diol (bronopol) in contact allergy and allergic contact dermatitis. These ubiquitous preservatives are still often, and sometimes undeclared, present in cosmetics, pharmaceuticals, medical devices, household detergents and chemical (industrial) products. In Europe, the use of free FA and quaternium-15 in cosmetics is forbidden and contact allergy rates have been found to be stable to decreasing. However, FA/FRs still readily provoke localized (e.g., facial/hand), airborne and generalized dermatitis, and may also complicate atopic and stasis dermatitis, or result in nummular dermatitis. Seborrheic-, rosacea- and impetigo-like dermatitis have recently been reported. For a correct diagnosis, FA 2% aq. (0.60 mg/cm² ) should be used, and particularly the FRs bronopol 0.5% pet. and diazolidinyl urea 2% should be patch tested separately in a baseline series. If sensitization to FA occurs, both FA and FRs should preferably be avoided, except perhaps for bronopol in case it tests negatively. If a patient reacts to one or more FRs (such as bronopol, or diazolidinyl/imidazolidinyl urea), but not to FA, then the specific FR(s) should be avoided. This article is protected by copyright. All rights reserved.

Delayed allergic skin reactions to vaccines

Background: Recent advances in vaccination against the severe acute respiratory syndrome coronavirus 2 pandemic have brought allergists and dermatologists to the forefront because both immediate and delayed hypersensitivity reactions have been reported. Objective: This literature review focused on delayed reactions to vaccines, including possible causative agents and practical information on how to diagnose, evaluate with patch testing, and manage subsequent dose administration. Methods: Currently published reviews and case reports in PubMed, along with data on vaccines from the Centers for Disease Control and Prevention web site. Relevant case reports and reviews that focused on delayed reactions to vaccines were selected. Results: Most delayed hypersensitivity reactions to vaccines include cutaneous manifestations, which vary from local persistent pruritic nodules to systemic rashes. The onset is usually within a few days but can be delayed by weeks. Multiple excipients have been identified that have been implicated in delayed vaccine reactions, including thimerosal, formaldehyde, aluminum, antibiotics, and gelatin. Treatment with antihistamines, topical corticosteroids, or systemic corticosteroids alleviates symptoms in most patients. Such reactions are generally not contraindications to future vaccination. However, for more-severe reactions, patch testing for causative agents can be used to aid in diagnosis and approach further vaccination. Conclusion: Delayed-type hypersensitivity reactions to vaccines are not uncommon. If needed, patch testing can be used to confirm agents, including antibiotics, formaldehyde, thimerosal, and aluminum. In most cases, delayed cutaneous reactions are not contraindications to further vaccine administration.

Controversy around parabens: Alternative strategies for preservative use in cosmetics and personal care products

Parabens usage as preservatives in cosmetics and personal care products have been debated among scientists and consumers. Parabens are easy to production, effective and cheap, but its safety status remains controversial. Other popular cosmetics preservatives are formaldehyde, triclosan, methylisothiazolinone, methylchloroisothiazolinone, phenoxyethanol, benzyl alcohol and sodium benzoate. Although their high antimicrobial effectiveness, they also exhibit some adverse health effects. Lately, scientists have shown that natural substances such as essential oils and plant extracts present antimicrobial potential. However, their use in cosmetic is a challenge. The present review article is a comprehensive summary of the available methods to prevent microbial contamination of cosmetics and personal care products, which can allow reducing the use of parabens in these products.

Prevalence of contact allergies in the population compared to a tertiary referral patch test clinic in Jena/Germany

BACKGROUND

The contact allergy prevalences in patch-tested patients are usually higher than those in the population, owing to morbidity-driven selection.

OBJECTIVES

To examine the differences between two samples, one from the population, one from the patch test clinic, in one area of Germany (Jena, Thuringia).

METHODS

Between August 2008 and October 2011, a total of 519 participants of the population-based european dermato-epidemiology network (EDEN) fragrance study were patch tested in Jena using a TRUE Test baseline series extended with some pet.-based (fragrance) allergen preparations. Between 2007 and 2012 (inclusive), 1906 routine patients were patch tested for suspected allergic contact dermatitis (ACD) in the Jena University Hospital Department; of these 1694 (83.2%) with the German baseline series using pet./aq.-based, investigator-loaded allergens.

RESULTS

In the population (clinical) sample, 19.6% (41.1%) were sensitized to at least one of the allergens considered. The most common baseline series allergens in the population/clinical sample were nickel (10.5%/13.2%), fragrance mix (FM) II (2.9%/6.7%), FM I (2.3%/8.3%), and cobalt (1.6%/5%). The clinical sample was slightly older (71.5% vs 55.9% age 40+) and included less males (36% vs 49.3%).

CONCLUSIONS

Results are quite similar, although prevalences are usually higher in the clinical setting, with the exception of p-tert-butylphenol formaldehyde resin.

Review of aluminum, paraben, and sulfate product disclaimers on personal care products

BACKGROUND

Product disclaimers listed on personal care products face limited regulation. These disclaimers may be helpful or may mislead the public.

OBJECTIVE

Review the evidence supporting the potential harms of three compounds commonly addressed by product disclaimers: parabens, aluminum, and sulfates.

METHODS

Reported cases of adverse events to these compounds were identified. Trends in allergic contact dermatitis to chemicals used in place of these compounds were also identified.

RESULTS

There is limited evidence that parabens and aluminum pose a threat to human health; there is even less evidence that topical sulfate containing products pose a danger to consumers. In the setting of paraben avoidence, there has been a steady increase in cases of allergic contact dermatitis to preservatives which are more allergenic, specifically the isothiazolinones.

LIMITATIONS

Assessment of the toxicology of these compounds is ongoing and may change with new data.

CONCLUSION

There is limited evidence that parabens, aluminum, and sulfates used in personal care products pose a health risk. There is evidence that avoidance of parabens has resulted in an epidemic of allergic contact dermatitis to isothiazolonine preservatives.

Next generation risk assessment for skin sensitisation: A case study with propyl paraben

Skin sensitisation is a key adverse health effect to be addressed in the safety assessment of cosmetic ingredients. Regulatory demands have urged the development of Next Generation Risk Assessment (NGRA) using New Approach Methodologies (NAM) and Defined Approaches (DA) instead of animal models. An illustrative NGRA case study shall demonstrate if the use of propyl paraben at 0.2% in a face cream was safe for consumers. A sequential stacking tier testing DA based on NAM data predicted propyl paraben to be a non-sensitiser, while some NAM input data showed positive results. To increase confidence, structurally related parabens were considered, which revealed NAM and DA hazard predictions similar to those of propyl paraben, non-sensitiser classifications in animal models and very rare cases of human skin allergy. Based on a weight of evidence it was decided that propyl paraben should be considered a non-sensitiser leading to a favourable NGRA conclusion, in line with traditional risk assessment. Examination of an ab initio NGRA based on NAM and metabolism data resulted in a more conservative weak sensitiser consideration as point of departure, which still led to a favourable conclusion.

Contact dermatitis associated with preservatives: Retrospective analysis of North American Contact Dermatitis Group data, 1994 through 2016

BACKGROUND

Preservatives are often necessary components of commercial products. Large-scale North American studies on preservative allergy are limited.

OBJECTIVE

To evaluate demographics, positive patch test reactions (PPTRs), clinical relevance, and trends for preservatives tested by the North American Contact Dermatitis Group.

METHODS

We conducted a retrospective cross-sectional analysis of North American Contact Dermatitis Group patch testing results of preservatives from 1994 through 2016.

RESULTS

A total of 50,799 patients were tested; 11,338 (22.3%) had a PPTR to at least 1 preservative. The most frequent reactions were to methylisothiazolinone 0.2% aqueous (aq) (12.2%), formaldehyde 2% aq (7.8%), formaldehyde 1% aq (7.8%), quaternium-15 2% petrolatum (pet) (7.7%), and methyldibromo glutaronitrile/phenoxyethanol 2% pet (5.1%). Paraben mix 12% pet (1%), iodopropynyl butylcarbamate 0.1% pet (0.4%), benzyl alcohol 1% pet (0.3%), and phenoxyethanol 1% pet (0.2%) had the lowest PPTRs. Linear regression analysis of preservatives tested showed that only methylchloroisothiazolinone/methylisothiazolinone 0.01% aq (parameter estimate, 0.42; 95% CI, 0.17-0.66; P < .005) had a significant increase in PPTRs over time.

LIMITATIONS

Collected variables are dependent on clinical judgment. Results may be prone to referral selection bias.

CONCLUSIONS

This large North American study provides insight on preservative PPTRs and trends from 1994 through 2016.

The application of pharmaceutical quality by design concepts to evaluate the antioxidant and antimicrobial properties of a preservative system including desferrioxamine

BACKGROUND

The purpose of the present study was to investigate the antioxidant and antimicrobial activities of a conventional preservative system containing desferrioxamine mesylate (DFO) and optimize the composition of the system through mathematical models.

METHODS

Different combinations of ethylenediaminetetraacetic acid (EDTA), sodium metabisulfite (SM), DFO and methylparaben (MP) were prepared using factorial design of experiments. The systems were added to ascorbic acid (AA) solution and the AA content over time, at room temperature and at 40 °C was determined by volumetric assay. The systems were also evaluated for antioxidant activity by a fluorescence-based assay. Antimicrobial activity was assessed by microdilution technique and photometric detection against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus brasiliensis. A multi-criteria decision approach was adopted to optimize all responses by desirability functions.

RESULTS

DFO did not extend the stability of AA over time, but displayed a better ability than EDTA to block the pro-oxidant activity of iron. DFO had a positive interaction with MP in microbial growth inhibition. The mathematical models showed adequate capacity to predict the responses. Statistical optimization aiming to meet the quality specifications of the ascorbic acid solution indicated that the presence of DFO in the composition allows to decrease the concentrations of EDTA, SM and MP.

CONCLUSION

DFO was much more effective than EDTA in preventing iron-catalyzed oxidation. In addition, DFO improved the inhibitory response of most microorganisms tested. The Quality by Design concepts aided in predicting an optimized preservative system with reduced levels of conventional antioxidants and preservatives, suggesting DFO as a candidate for multifunctional excipient.

A perspective on the safety of parabens as preservatives in wound care products

Antimicrobial and/or preservative ingredients incorporated in wound care products are subjected to certain safety restrictions. However, several of those agents, and paraben preservatives in particular, have been criticised. Conflicting reports on the potential of parabens to induce allergic contact dermatitis, and their assumed oestrogen‐like activity, raised public health concerns about their overall safety. Here, we seek to provide a balanced perspective on the most significant purported adverse health effects, and thereby allay the many misconceptions regarding the safety of parabens. Extensive and long‐term monitoring of paraben allergy frequencies illustrate that allergic reactions are quite uncommon, especially when compared with other antimicrobial and preservative agents. The estrogenic potential of parabens was illustrated to be far less potent than that of natural oestrogen receptor ligands, and the etiological significance of their presence in human tissue has not been established. The general consensus based on investigations by both the scientific community and regulatory agencies indicates that, with current safety regulations regarding their use in place, this effective and well‐documented group of preservatives should not warrant drastic measures to replace them. As such, despite the ongoing concern, it is indicated that, when used at typical concentrations, parabens are unlikely to affect human health.

Do Claims about the Naturalness and Dose of Cosmetics Ingredients Affect the Public’s Perception of Their Safety?

Media articles have claimed that “synthetic mineral oil saturated hydrocarbons (MOSH)”, which are used in many cosmetics such as lip balms, are unsafe at any dose and should be replaced with natural alternatives. This paper examines whether these claims are correct and whether the perceived safety of these substances is influenced by the language used in the media. To achieve these goals, it first provides an extensive review of the toxicology literature, finding no support that MOSHs are unsafe at current usage levels. It then reviews the psychology literature to examine the effects of labelling a cosmetic ingredient as “natural” rather than “synthetic” and the effects of dose information. A 2 × 2 between-subjects experiments involving adult lip balm users shows that, as hypothesized, the perceived safety of lip balms increases when they are described as containing “naturally sourced mineral oil” rather than “synthetic mineral oil saturated hydrocarbon (MOSH)”, which are both correct descriptions. In addition, the perceived safety increases when the substance is described as being present in a low vs. a high dose, regardless of whether it was described as natural or synthetic. Overall, safety perceptions for common cosmetic substances can be significantly influenced by the language used in media reporting.

Risk factors for frontal fibrosing alopecia: A case-control study in a multiracial population

BACKGROUND

Frontal fibrosing alopecia (FFA) is a chronic cicatricial alopecia with unknown etiology and a worldwide rising incidence.

OBJECTIVE

The objective of this study was to evaluate the association of FFA with demographic and exposure factors in a Brazilian multiracial population.

METHODS

A multicenter case-control study was conducted in 11 referral centers throughout Brazil. The study was a case-control study that prospectively recruited 902 participants (451 patients with FFA and 451 sex-matched control individuals). Study participants completed a thorough questionnaire comprising variables grouped as baseline demographics, environmental exposure, diet, hormonal factors, allergies, and hair and skin care.

RESULTS

When adjusted by sex, age, menopause, and skin color, FFA was associated with hair straightening with formalin (odds ratio [OR], 3.18), use of ordinary (nondermatologic) facial soap (OR, 2.09) and facial moisturizer (OR, 1.99), thyroid disorders (OR, 1.69), and rosacea (OR, 2.08). Smokers (OR, 0.33) and users of antiresidue/clarifying shampoo (OR, 0.35) presented a negative association with FFA. There was no association with the use of sunscreen.

LIMITATIONS

Recall bias.

CONCLUSIONS

The association with moisturizers, ordinary facial soap, and hair straightening with formalin and the negative association with antiresidue/clarifying shampoo reinforce the possibility of an exogenous particle triggering FFA.

Patch test results of the European baseline series among 1309 patients in Turkey between 2013 and 2019

BACKGROUND

Prevalences of sensitivity to contact allergens change over time as a result of variations in allergen exposure.

OBJECTIVES

The aim of the study was to describe trends in sensitisation to allergens of the European baseline series in Turkey between 2013 and 2019.

METHODS

The patch test results of 1309 patients with suspected allergic contact dermatitis (ACD) were analysed retrospectively, and the prevalence of contact allergies to European baseline series allergens was compared with previous data (for 1998-2005).

RESULTS

A total of 534 (40.8%) patients exhibited one or more positive patch test reaction. The five most frequent allergens were nickel sulfate (19.6%), potassium dichromate (6.5%), cobalt chloride (6%), Myroxylon pereirae resin (5%), and p-phenylenediamine (PPD; 3.7%). Statistically significant increases in the prevalence of sensitisation to methylchloroisothiazolinone/methylisothiazolinone (MCI/MI; P < .001), Myroxylon pereirae resin (P < .001), PPD (P = .008), and fragrance mix I (P = .036) were observed in the 2013 to 2019 period compared with the 1998 to 2005 period. Conversely, positive reactions to neomycin sulfate (P = .029), clioquinol (P = .031), and primin (P = .001) decreased significantly.

CONCLUSION

This study provides a comprehensive profile of ACD in Turkey. The remarkable increase in the MI and MCI/MI contact allergy observed underlines the urgent need for regulatory measures to reduce exposure to MI and MCI/MI in Turkey.

Skin irritation potential of cosmetic preservatives: An exposure-relevant study

BACKGROUND

Preservatives represent one of the main causes of skin irritation and contact allergies.

AIMS

To comprehensively evaluate the skin irritation potential of phenoxyethanol, methylparaben, propylparaben, imidazolidinyl urea, and DMDM hydantoin under regulatory acceptable concentrations.

METHODS

A patch test and repeated open application test (ROAT) were applied to evaluate skin irritation in vivo. In vitro alternative methods consisting of the keratinocyte cytotoxicity assay, red blood cell (RBC) test, and hen's egg test-chorioallantoic membrane (HET-CAM) were performed to elucidate the mechanism of preservative-induced irritation responses.

RESULTS

The patch test showed that all test substances showed a weak erythema response. Propylparaben had the highest occlusive irritancy potential in the patch test, owing to damage to the cell membrane. The two formaldehyde releasers showed noticeable skin irritation potential in the ROAT through their cytotoxicity to keratinocytes, while a visible response was observed after applying phenoxyethanol and the two parabens. No filtration was noticed in the in vivo tests, which might be attributed to the failure of subcutaneous vessel alteration by the preservatives.

CONCLUSIONS

Commonly used cosmetic preservatives have minor skin irritation potential with mild erythema reaction under practical use, especially formaldehyde releasers and propylparaben.

What is in? What is out? Updating the British Society for Cutaneous Allergy facial series

BACKGROUND

Allergic contact dermatitis (ACD) to cosmetics is widely reported. To ensure we are accurately diagnosing ACD, patch test series should be continually reviewed to identify relevant and emerging allergens and highlight those that are outdated. The current British Society for Cutaneous Allergy (BSCA) facial series recommends 26 allergens and was last modified in 2012.

OBJECTIVES

To review and update the BSCA facial series.

METHODS

We retrospectively reviewed the results from 12 UK and Ireland patch test centres' facial series from January 2016 to December 2017. We recorded the number of allergens tested in each centre and the detection rate for each allergen. Using a 0·3% positive rate as the inclusion threshold, we established which allergens in the BSCA facial series had positive patch test rates < 0·3% and > 0·3%. Allergens not in the BSCA facial series that had a positive patch test rate > 0·3% were identified.

RESULTS

Overall, 4224 patients were patch tested to the facial series. The number of allergens included in individual centres' facial series ranged from 24 to 66, with a total of 103 allergens tested across all centres. Twelve of the 26 allergens in the BSCA facial series had a positive patch test rate < 0·3% and 14 had a rate > 0·3%. Twenty-five allergens not recommended in the BSCA facial series had a positive patch test rate > 0·3%.

CONCLUSIONS

This audit has highlighted the significant variation in practice that exists among patch test centres, despite a recommended facial series. The BSCA facial series has been updated and now contains 24 allergens. Fifteen allergens remain, 11 allergens have been dropped and nine new allergens have been added.

Investigating exposure to endocrine disruptors via hair analysis of pregnant women

The aim of this study was the monitoring of the levels of parabens (PBs) and triclosan (TCS) in head hair samples of women collected during the first months of their pregnancy. Personal details concerning somatometric and demographic characteristics, dietary habits, use of personal care products and the medical and obstetrical history of the pregnant women as well as infants' somatometric characteristics and health condition were recorded through relevant questionnaires. Ninety five hair samples were collected, extracted by solid-liquid extraction and analysed using a liquid chromatography-mass spectrometry system (LC-MS). Analysis revealed high percentage of positive samples for all tested compounds (90-100% except from BePB (15.8%)). The mean concentration levels were 4501.2 pg/mg (17.6-27,437.0 pg/mg) for MePB; 510.1 pg/mg (11.0-4224.5 pg/mg) for EtPB; 22.9 pg/mg (2.1-66.6 pg/mg) for BePB; 237.1 pg/mg (1.8-2513.7 pg/mg) for BuPB and 245.0 pg/mg (8.8-8070.2 pg/mg) for TCS. Statistical analysis of both analytical results and questionnaires' data showed that the frequent use of personal care and hygiene products, such as makeup, hairspray and sunscreens, is correlated with higher levels of PBs in hair of the pregnant women. Additionally, positive correlation was observed between the BePB levels in hair and the infants' height. Finally, no other correlation was observed between endocrine disruptors' levels in maternal hair and infants' somatometric characteristics or health condition. Our study is the first one that determined PBs and TCS levels in hair samples, simultaneously. At the same time, correlation of the detected levels with the use of personal care products was accomplished, leading to significant association of BePB levels in hair of pregnant women with infants' height.

Douching, Talc Use, and Risk for Ovarian Cancer and Conditions Related to Genital Tract Inflammation

BACKGROUND

Douching is associated with disorders involving genital tract inflammation and genital talc use with epithelial ovarian cancer (EOC), but their joint effects are infrequently considered.

METHODS

From 2,040 cases of EOC and 2,100 controls enrolled in eastern Massachusetts and New Hampshire, we used unconditional logistic regression to estimate risk for EOC associated with douching and/or talc use. In subsets of cases and controls, we also collected information about pelvic inflammatory disease (PID), ectopic pregnancy, and cervical neoplasia to estimate risk for these events from douching and/or talc use.

RESULTS

The adjusted OR and 95% confidence interval (CI) for all EOC was 0.94 (0.76-1.16) in women who douched but never used talc and 1.28 (1.09-1.51) in women who used talc but never douched. Compared with women who never regularly douched or used talc, ORs (95% CIs) were 0.83 (0.52-1.33) for women who both used talc and homemade douches and 1.53 (1.11-2.10) for women who both used talc and store-bought douches. Cases who both douched and used talc were more likely to have had PID compared with cases who had used neither [OR = 5.03 (95% CI, 1.61-15.7)].

CONCLUSIONS

Douching is not an independent risk factor for ovarian cancer, but the combination of talc use and store-bought douches may modestly increase the risk for EOC beyond that for talc use alone.

IMPACT

The joint effect of talc use and douching, especially with commercial products, should be considered in evaluating risks associated with disorders involving genital tract inflammation or EOC.

Contact Sensitization to Formaldehyde in Veterinary Medicine - An Unexplored Field in Occupational Health

Background:

Veterinary staff and students could be exposed to formaldehyde – a ubiquitous agent, common cause of contact allergy.

Aim:

To evaluate the incidence of contact sensitization to formaldehyde in exposures in veterinary medicine.

Settings and Design:

A cross-sectional study was conducted during July–December 2017.

Materials and Methods:

A total of 206 individuals were included, patch tested with formaldehyde 1.0%/aq – 36 veterinary medicine students, 20 veterinarians, 47 students and 28 trainees of dental medicine, 41 dental professionals, and 35 non-occupationally exposed individuals.

Results:

The incidence of contact sensitization to formaldehyde among the whole studied population was 48.1%, highest being among the students of veterinary medicine (94.4%) and the veterinarians (85%). With very high significance, the sensitization incidence was higher in the groups of students of veterinary medicine and veterinarians, if compared to the control group (P < 0.001); (P = 0.004), dental professionals (P < 0.001); (P = 0.001), trainees of dental medicine (P < 0.001); (P = 0.005), and students of dental medicine three-fourth year of education (P < 0.001); (P = 0.001). Significantly, higher was the incidence of contact allergy in the control group if compared to those of dental professionals (P = 0.033) and dental students three-fourth year of education (P = 0.028).

Conclusions:

The exposure to formaldehyde during the education in veterinary medicine and practice could be an important risk factor for the onset of contact sensitization. Stricter preventive measures are needed to reduce veterinary student's and lecturer's exposures. Equipment of dissection tables with local exhaust ventilation system could reduce the concentration of formaldehyde in the gross anatomy laboratory.

Skin Sensitization to Fluorescein Isothiocyanate Is Enhanced by Butyl Paraben in a Mouse Model

Contact hypersensitivity (CHS) to preservatives is receiving increased attention. Parabens are widely used in foods, pharmaceutics and cosmetics as preservatives. The skin sensitizing activity of parabens remains controversial but a few investigations have been made as to whether parabens could facilitate sensitization to other chemicals. We have shown that di-n-butyl phthalate (DBP), a phthalate ester, has an adjuvant effect in a fluorescein isothiocyanate (FITC)-induced CHS mouse model. We have also demonstrated that DBP activates transient receptor potential ankyrin 1 (TRPA1) cation channels expressed on sensory neurons. Comparative studies of phthalate esters revealed that TRPA1 agonistic activity and the adjuvant effect on FITC-CHS coincide. Here we focused on two commonly used parabens, butyl paraben (BP) and ethyl paraben (EP), as to their adjuvant effects. BALB/c mice were epicutneously sensitized with FITC in acetone in the presence or absence of a paraben. Sensitization to FITC was evaluated as the ear-swelling response after FITC challenge. BP but not EP enhanced skin sensitization to FITC, but the effect of BP was much weaker than that of DBP. Mechanistically, BP enhanced the trafficking of FITC-presenting CD11c⁺ dendritic cells (DCs) from the skin to draining lymph nodes as well as cytokine production by draining lymph nodes. When the TRPA1 agonistic activity was measured with a cell line expressing TRPA1, BP exhibited higher activity than EP. The present study provides direct in vivo evidence that BP causes sensitization to other chemicals by means of a mouse FITC-CHS model.

Pathomechanisms of Contact Sensitization

Contact sensitization is the initial process involved in the development of an allergic reaction to xenobiotic environmental substances. Here, we briefly describe the differences between irritant and allergic contact dermatitis. Then, we highlight the essential steps involved in the development of an ACD reaction, i.e., the protein binding of haptens, genetic factors influencing the penetration of sensitizers into the skin, the different mechanisms driving the initial development of an inflammatory cytokine micromilieu enabling the full maturation of dendritic cells, the role of pre- and pro-haptens, antigen presentation and T cell activation via MHC and CD1 molecules, dendritic cell (DC) migration, and potential LC contribution as well as the different T cell subsets involved in ACD. In addition, we discuss the latest publications regarding factors that might influence the sensitizing potential such as repeated sensitizer application, penetration enhancers, humidity of the skin, microbiota, Tregs, and phthalates. Last but not least, we briefly touch upon novel targets for drug development that might serve as treatment options for ACD.