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.

Chemical Modifications Induced by Phthalic Anhydride, a Respiratory Sensitizer, in Reconstructed Human Epidermis: A Combined HRMAS NMR and LC-MS/MS Proteomic Approach

Chemical skin and respiratory allergies are becoming a major health problem. To date our knowledge on the process of protein haptenation is still limited and mainly derived from studies performed in solution using model nucleophiles. In order to better understand chemical interactions between chemical allergens and the skin, we have investigated the reactivity of phthalic anhydride 1 (PA), a chemical respiratory sensitizer, toward reconstructed human epidermis (RHE). This study was performed using a new approach combining HRMAS NMR to investigate the in situ chemical reactivity and LC-MS/MS to identify modified epidermal proteins. In RHE, the reaction of PA appeared to be quite fast and the major product formed was phthalic acid. Two amide type adducts on lysine residues were observed and after 8h of incubation, we also observed the formation of an imide type cyclized adducts with lysine. In parallel, RHE samples topically exposed to phthalic anhydride (¹³C)-1 were analyzed using the shotgun proteomics method. Thus, 948 different proteins were extracted and identified, 135 of which being modified by PA, i.e., 14.2% of the extracted proteome. A total of 211 amino acids were modified by PA and validated by fragmentation spectra. We thus identified 154 modified lysines, 22 modified histidines, 30 modified tyrosines, and 5 modified arginines. The rate of modified residues, as a proportion of the total number of modifiable nucleophilic residues in RHE, was rather low (1%). At the protein level, modified proteins were mainly type I and type II keratins and other proteins which are abundant in the epidermis such as protein S100A, Caspase 14, annexin A2, serpin B3, fatty-acid binding protein 5, histone H2, H3, H4, etc. However, the most modified protein, mainly on histidine residues, was filaggrin, a protein that is of low abundance (0.0266 mol %) and rich in histidine.

Single- and repeated-dose 28-day oral toxicity study of MDM hydantoin in Sprague-Dawley rats

1-(hydroxymethyl)-5,5-dimethylimidazolidine-2,4-dione (MDM hydantoin) is a commonly used antiseptic preservative in cosmetics. However, limited toxicity information data are available for this chemical. The aim of this study was to obtain toxicity data for MDM hydantoin through single- and repeated-dose toxicity studies in Sprague-Dawley (SD) rats. In the single-dose toxicity study, MDM hydantoin was administered once orally to SD rats at four doses (5, 50, 300, and 2000 mg/kg/day). There was no significant difference in mortality, clinical signs, and body weight change for 14 days among the animals treated with the different doses in this study. Hence, the approximate lethal dose of MDM hydantoin was considered higher than 2000 mg/kg/day. Based on the results of the dose-range finding study, a 28-day repeated-dose oral toxicity study was conducted. MDM hydantoin was administered orally to SD rats at doses of 125, 250, 500, and 1000 mg/kg/day throughout an experimental period of 28 days. In the repeated-dose oral toxicity study, the adverse effects caused by MDM hydantoin were not detected in terms of body weight, clinical signs, food and water intake, hematology, organ weights, gross pathology, and histopathology. Therefore, the no-observed-adverse-effect level of MDM hydantoin was considered to be greater than 1000 mg/kg/day.

Hidden Formaldehyde Content in Cosmeceuticals Containing Preservatives that Release Formaldehyde and Their Compliance Behaviors: Bridging the Gap between Compliance and Local Regulation

Background: Many personal care products, and particularly cosmetic products, contain preservatives that release formaldehyde. These are potentially harmful to consumer health, especially considering that the levels of formaldehyde in some products are hidden and excessive. Objectives: To study the formaldehyde levels of preservatives in personal care products and cosmetics on the UAE market and determine the extent of compliance with health and safety requirements. Methods and Materials: Sixty-nine personal care and cosmetic product samples from the UAE market were collected and prepared to determine their formaldehyde content. According to the Second European Commission Directive 82/434/EEC of 2000 and as per the Gulf Technical Regulation, Safety Requirements of Cosmetics and Personal Care Products in GSO 1943:2016, quantitative analyses were performed to identify and quantify the content of formaldehyde as free formaldehyde. Results: With a maximum permissible limit of ≤0.2% w/w, the average formaldehyde content was found to be 0.083 with a 95% CI (0.039–0.13). Nine of the tested personal care and cosmetic products exceeded the recommended formaldehyde level, corresponding to 13% of all samples. None of these samples listed the free formaldehyde content or formaldehyde releaser. Conclusion: Applying good manufacturing practices (GMP), education, and regulatory control to improve the regulation and inspection of cosmetics containing formaldehyde releasers as preservatives, conducting research, and reporting the adverse side effects are highly recommended. There is an urgent need to monitor the incidence of skin sensitivity resulting from the use of cosmetics containing formaldehyde releasers as preservatives.

Formaldehyde 2% is not a useful means of detecting allergy to formaldehyde releasers- results of the ESSCA network, 2015-2018

BACKGROUND

Studies suggest that patch testing with formaldehyde releasers (FRs) gives significant additional information to formaldehyde 1% aq. and should be considered for addition to the European baseline series (EBS). It is not known if this is also true for formaldehyde 2% aq.

OBJECTIVES

To determine the frequency of sensitization to formaldehyde 2% aq. and co-reactivity with FRs. To establish whether there is justification for including FRs in the EBS.

MATERIALS AND METHODS

A 4-year, multi-center retrospective analysis of patients with positive patch test reactions to formaldehyde 2% aq. and five FRs.

RESULTS

A maximum of 15 067 patients were tested to formaldehyde 2% aq. and at least one FR. The percentage of isolated reactions to FR, without co-reactivity to, formaldehyde 2% aq. for each FR were: 46.8% for quarternium-15 1% pet.; 67.4% imidazolidinyl urea 2% pet.; 64% diazolidinyl urea 2% pet.; 83.3% 1,3-dimethylol-5, 5-dimethyl hydantoin (DMDM) hydantoin 2% pet. and 96.3% 2-bromo-2-nitropropane-1,3-diol 0.5% pet. This demonstrates that co-reactivity varies between FRs and formaldehyde, from being virtually non-existent in 2-bromo-2-nitropropane-1,3-diol 0.5% pet. (Cohen's kappa: 0, 95% confidence interval [CI] -0.02 to 0.02)], to only weak concordance for quaternium-15 [Cohen's kappa: 0.22, 95%CI 0.16 to 0.28)], where Cohen's kappa value of 1 would indicate full concordance.

CONCLUSIONS

Formaldehyde 2% aq. is an inadequate screen for contact allergy to the formaldehyde releasers, which should be considered for inclusion in any series dependant on the frequency of reactions to and relevance of each individual allergen.

A novel quantification method for sulfur-containing biomarkers of formaldehyde and acetaldehyde exposure in human urine and plasma samples

A novel method for the quantification of the sulfur-containing metabolites of formaldehyde (thiazolidine carboxylic acid (TCA) and thiazolidine carbonyl glycine (TCG)) and acetaldehyde (methyl thiazolidine carboxylic acid (MTCA) and methyl thiazolidine carbonyl glycine (MTCG)) was developed and validated for human urine and plasma samples. Targeting the sulfur-containing metabolites of formaldehyde and acetaldehyde in contrast to the commonly used biomarkers formate and acetate overcomes the high intra- and inter-individual variance. Due to their involvement in various endogenous processes, formate and acetate lack the required specificity for assessing the exposure to formaldehyde and acetaldehyde, respectively. Validation was successfully performed according to FDA's Guideline for Bioanalytical Method Validation (2018), showing excellent performance with regard to accuracy, precision, and limits of quantification (LLOQ). TCA, TCG, and MTCG proved to be stable under all investigated conditions, whereas MTCA showed a depletion after 21 months. The method was applied to a set of pilot samples derived from smokers who consumed unfiltered cigarettes spiked with ¹³C-labeled propylene glycol and ¹³C-labeled glycerol. These compounds were used as potential precursors for the formation of ¹³C-formaldehyde and ¹³C-acetaldehyde during combustion. Plasma concentrations were significantly lower as compared to urine, suggesting urine as suitable matrix for a biomonitoring. A smoking-related increase of unlabeled biomarker concentrations could not be shown due to the ubiquitous distribution in the environment. While the metabolites of ¹³C-acetaldehyde were not detected, the described method allowed for the quantification of ¹³C-formaldehyde uptake from cigarette smoking by targeting the biomarkers ¹³C-TCA and ¹³C-TCG in urine.Graphical abstract.

Toward safer thanatopraxy cares: formaldehyde-releasers use

Human cadavers constitute very useful educational tools to teach anatomy in medical scholarship and related disciplines such as physiology, for example. However, as biological material, human body is subjected to decay. Thanatopraxy cares such as embalming have been developed to slow down and inhibit this decay, but the formula used for the preservation fluids are mainly formaldehyde (FA)-based. Very recently, other formulas were developed in order to replace FA, and to avoid its toxicity leading to important environmental and professional exposure concerns. However, these alternative FA-free fluids are still not validated or commercialized, and their efficiency is still under discussion. In this context, the use of FA-releasing substances, already used in the cosmetics industry, may offer interesting alternatives in order to reduce professional exposures to FA. Simultaneously, the preservation of the body is still guaranteed by FA generated over time from FA-releasers. The aim of this review is to revaluate the use of FA in thanatopraxy cares, to present its benefits and disadvantages, and finally to propose an alternative to reduce FA professional exposure during thanatopraxy cares thanks to FA-releasers use.

Undeclared formaldehyde levels in patient consumer products: formaldehyde test kit utility

PURPOSE

Formaldehyde allergic contact dermatitis (ACD) may be due to products with free formaldehyde or formaldehyde-releasing agents; however, assessment of formaldehyde levels in such products is infrequently conducted. The present study quantifies total releasable formaldehyde from "in-use" products associated with formaldehyde ACD and tests the utility of commercially available formaldehyde spot test kits.

MATERIALS AND METHODS

Personal care products from 2 patients with ACD to formaldehyde were initially screened at the clinic for formaldehyde using a formaldehyde spot test kit. Formaldehyde positive products were sent to the laboratory for confirmation by gas chromatography-mass spectrometry. In addition, 4 formaldehyde spot test kits were evaluated for potential utility in a clinical setting.

RESULTS

Nine of the 10 formaldehyde spot test kit positive products obtained from formaldehyde allergic patients had formaldehyde with total releasable formaldehyde levels ranging from 5.4 to 269.4 µg/g. Of these, only two shampoos tested listed a formaldehyde-releasing agent in the ingredients or product literature. Subsequently, commercially available formaldehyde spot test kits were evaluated in the laboratory for ability to identify formaldehyde in personal care products.

CONCLUSIONS

Chemical based formaldehyde spot test were more reliable than the enzymatic based test in identifying product releasable formaldehyde content. It is concluded that product labeled ingredient lists and available information are often inadequate to confirm the potential for formaldehyde exposure and chemical based spot test kits may have utility for identification of potential formaldehyde exposure from personal care products.

Cosmetics Preservation: A Review on Present Strategies

Cosmetics, like any product containing water and organic/inorganic compounds, require preservation against microbial contamination to guarantee consumer’s safety and to increase their shelf-life. The microbiological safety has as main goal of consumer protection against potentially pathogenic microorganisms, together with the product’s preservation resulting from biological and physicochemical deterioration. This is ensured by chemical, physical, or physicochemical strategies. The most common strategy is based on the application of antimicrobial agents, either by using synthetic or natural compounds, or even multifunctional ingredients. Current validation of a preservation system follow the application of good manufacturing practices (GMPs), the control of the raw material, and the verification of the preservative effect by suitable methodologies, including the challenge test. Among the preservatives described in the positive lists of regulations, there are parabens, isothiasolinone, organic acids, formaldehyde releasers, triclosan, and chlorhexidine. These chemical agents have different mechanisms of antimicrobial action, depending on their chemical structure and functional group’s reactivity. Preservatives act on several cell targets; however, they might present toxic effects to the consumer. Indeed, their use at high concentrations is more effective from the preservation viewpoint being, however, toxic for the consumer, whereas at low concentrations microbial resistance can develop.

Using thermal desorption electrospray ionization mass spectrometry to rapidly determine antimicrobial preservatives in cosmetics

RATIONALE

Characterization and quantification of permitted preservatives are important inspections to prevent the overuse of preservatives in authentic formulations. However, the complexity of sample matrices makes preservative determination in cosmetics a tedious process. A rapid analytical strategy to identify preservatives would insure large numbers of products are in compliance with government regulations.

METHODS

Thermal desorption electrospray ionization mass spectrometry (TD-ESI-MS) was used to directly detect preservative compounds in authentic formulations without sample pretreatment. The technique employs a metal probe, which was configured for sampling cosmetics in their original states and was inserted in a closed preheated oven to thermally desorb analytes. The desorbed analytes were then carried by a nitrogen gas stream into an ESI plume, where the formed ions were subsequently detected by the mass analyzer.

RESULTS

The TD-ESI mass and tandem mass spectra of different classes of preservative standards were rapidly obtained, and the limits of detection were far below the legal limit of their respective concentrations. The preservatives were also directly detected in different types of authentic formulations in the absence of sample preparation, and within a few seconds per sample. Calibration curves for preservatives in four common formulations yielded good linearity in the regulation-allowed range.

CONCLUSIONS

Due to its sensitivity, short analysis time, repeatability, and quantitative ability, TD-ESI-MS may serve as a suitable tool for large-scale screening of cosmetic preservatives to assure product safety. Copyright © 2016 John Wiley & Sons, Ltd.

Sensitization to Formaldehyde in Northeastern Italy, 1996 to 2012

BACKGROUND

Formaldehyde is a widely used organic compound, used in several applications (hard thermoset resins, adhesives, disinfectants, tissue fixatives, etc), in its free form or released by formaldehyde releaser products. Its use is under control due to its toxic, carcinogenic, and allergenic properties.

OBJECTIVE

The aim of this study was to investigate the frequency of formaldehyde sensitization, time trend, and correlation to occupations.

METHODS

This study is a cross-sectional study on a population of 23,774 patients tested from 1996 to 2012 in Northeastern Italy.

RESULTS

Frequency of sensitization was 3.3%, without any significant time trend. Hands (39.8% overall) and face (25.6% females, 15.5% males) were mainly involved. We found a trend toward decrease by age in females (3.11% in first quintile [14-26 years], 2.29% in fifth quintile [59-97 years], P < 0.01). On a logistic regression analysis (control group: white-collar workers), we found associations in health care (odds ratio [OR], 1.37; 95% confidence interval [CI], 1.04-1.81), wood (OR, 2.14; 95% CI, 1.30-3.51), and textile (OR, 1.79; 95% CI, 1.14-2.79) sectors and professional drivers (OR, 1.94; 95% CI, 1.05-3.60). We found a high rate of cosensitization to formaldehyde in patients with positive patch test reactions to quaternium-15 (OR, 18.7; 95% CI, 12.6-27.7).

CONCLUSIONS

Sensitization to formaldehyde is relevant in our population, especially in the health care sector, wood and textile industries, and professional drivers. No significant time trend was found.

In situ chemical behaviour of methylisothiazolinone (MI) and methylchloroisothiazolinone (MCI) in reconstructed human epidermis: a new approach to the cross-reactivity issue

BACKGROUND

Methylisothiazolinone (MI) [with methylchloroisothiazolinone (MCI) in a ratio of 1:3, a well-recognized allergenic preservative] was released as an individual preservative in the 2000s for industrial products and in 2005 for cosmetics. The high level of exposure to MI since then has provoked an epidemic of contact allergy to MI, and an increase in MI/MCI allergy. There are questions concerning the MI/MCI cross-reaction pattern.

OBJECTIVES

To bring a new perspective on the MI/MCI cross-reactivity issue by studying their in situ chemical behaviour in 3D reconstructed human epidermis (RHE).

METHODS

MI and MCI were synthesized with (13) C substitution at positions C-4/C-5 and C-5, respectively. Their in situ chemical behaviours in an RHE model were followed by use of the high-resolution magic angle spinning nuclear magnetic resonance technique.

RESULTS

MI was found to react exclusively with cysteine thiol residues, whereas MCI reacted with histidines and lysines. The reaction mechanisms were found to be different for MI and MCI, and the adducts formed had different molecular structures.

CONCLUSION

In RHE, different MI/MCI reactions towards different nucleophilic amino acids were observed, making it difficult to explain cross-reactivity between MI and MCI.

Pharmacologic alternatives to riboflavin photochemical corneal cross-linking: a comparison study of cell toxicity thresholds

PURPOSE

The efficacy of therapeutic cross-linking of the cornea using riboflavin photochemistry (commonly abbreviated as CXL) has caused its use to become widespread. Because there are known chemical agents that cross-link collagenous tissues, it may be possible to cross-link tissue pharmacologically. The present study was undertaken to compare the cell toxicity of such agents.

METHODS

Nine topical cross-linking agents (five nitroalcohols, glyceraldehyde [GLYC], genipin [GP], paraformaldehyde [FA], and glutaraldehyde [GLUT]) were tested with four different cell lines (immortalized human corneal epithelial cells, human skin fibroblasts, primary bovine corneal endothelial cells, and immortalized human retinal pigment epithelial cells [ARPE-19]). The cells were grown in planar culture and exposed to each agent in a range of concentrations (0.001 mM to 10 mM) for 24 hours followed by a 48-hour recovery phase. Toxicity thresholds were determined by using the trypan blue exclusion method.

RESULTS

A semiquantitative analysis using five categories of toxicity/fixation was carried out, based on plate attachment, uptake of trypan blue stain, and cellular fixation. The toxicity levels varied by a factor of 10(3) with the least toxic being mononitroalcohols and GLYC, intermediate toxicity for a nitrodiol and nitrotriol, and the most toxic being GLUT, FA, GP, and bronopol, a brominated nitrodiol. When comparing toxicity between different cell lines, the levels were generally in agreement.

CONCLUSIONS

There are significant differences in cell toxicity among potential topical cross-linking compounds. The balance between cross-linking of tissue and cell toxicity should be borne in mind as compounds and strategies to improve mechanical tissue properties through therapeutic tissue cross-linking continue to develop.

Carbon-13 nuclear magnetic resonance analysis of formaldehyde free preservatives

Preservation of biomolecules is pivotal in increasingly important molecular diagnostics. Traditionally, formaldehyde is employed for such biomolecular preservation in spite of its carcinogenicity. Moreover, formaldehyde induced cross-linking during fixation is reported to alter structural and functional properties of the preserved biomolecules. Therefore, formaldehyde-free preservatives are advantageous because they are safer for laboratory personnel and they protect the structural and functional integrity of the biomolecules. Streck Cell Preservative and Cell-Free DNA BCT reagents are used as formaldehyde alternative preservatives. However, no studies have been carried out to evaluate formaldehyde concentrations in these preservatives. In this study, we evaluated the free formaldehyde concentrations of these reagents by carbon-13 ((13)C) NMR spectroscopic analysis. Chemically non-invasive NMR analysis is more reliable than the traditional derivatization based techniques in formaldehyde detection. (13)C NMR technique can be used for quantitative measurement by using (13)C NMR-relaxation agents. In this manuscript, we report an optimized NMR analysis method using Gadolinium diethylenetriaminepentaacetate. Additionally the data reported herein provide spectral analyses that indicate Streck Cell Preservative and Cell-Free DNA BCT reagents do not contain detectable free formaldehyde. Therefore, these preservatives are safer alternatives than formaldehyde for laboratory use, which can protect the overall integrity of the biomolecules within preserved samples.