Trends in preservative allergy: Benzisothiazolinone emerges from the pack

Skin sensitisation elicitation: Evaluation of the general threshold and considerations for use

BACKGROUND

Allergic contact dermatitis (ACD) is an immune response to chemical haptens, involving induction and elicitation phases. Quantitative risk assessment (QRA) reviewing the skin sensitisation potential for all ingredients and using chemical-specific induction thresholds for skin allergens remains the current best approach for the safety evaluation of consumer products. However, elicitation thresholds have utility in secondary protection for pre-sensitised consumers.

OBJECTIVES

The objectives were to (1) review the current elicitation threshold database, (2) evaluate whether predicted relationships between chemical induction and elicitation potencies enable elicitation threshold prediction and (3) discuss elicitation threshold utility as a secondary method of consumer protection.

METHODS

In total, 28 publications (with 39 elicitation datasets) were included in non-linear regression analysis to derive elicitation thresholds for 22 allergens, including fragrances, preservatives and metals.

RESULTS

The median elicitation threshold (ED10) for the expanded database was 0.95 μg/cm2, which supports previously published general elicitation thresholds. The derived ED10 for each chemical had only weak to moderate correlation with corresponding induction thresholds, thus limiting suitability as the predictive model.

CONCLUSIONS

Assessment of current EU fragrance allergen labelling and sensitiser labelling under the globally harmonised system in the context of general and chemical-specific elicitation thresholds shows that current practices are health protective.

Incidence of allergic contact dermatitis in Finland 1998-2021: A nationwide registry-based study

BACKGROUND

Allergic contact dermatitis (ACD) may be chronic and can cause distress, disability, and absence from work. Nationwide epidemiological studies of ACD are sparse.

OBJECTIVES

To use national registry data to study the incidence and aetiology of ACD in the working age population of Finland.

METHODS

Patient records from the years 1998-2021 were obtained from the Finnish Care Register for Health Care. Study subjects aged 18-65 years were selected on the basis of a diagnosis of ACD.

RESULTS

Total number of study subjects was 26 701. The incidence of ACD increased until 2016 after which it started to decrease. The increase was more marked in females and ACD was particularly common in women reporting reactions to cosmetics and other chemical products and in people of both sexes reacting to adhesives. The incidence 'ACD of unspecific cause' has decreased since 2016. The most commonly reported allergens were metals, followed by cosmetics. One fourth of subjects had ≥2 ACD diagnoses.

CONCLUSIONS

The incidence of ACD in working age subjects rose from 1998 to 2016, especially in females. However, the incidence has been decreasing since 2016. Our findings highlight the ongoing and even increasing burden of ACD among the working age population.

Effects of Kimchi-Derived Lactic Acid Bacteria on Reducing Biological Hazards in Kimchi

This study was performed to investigate the use of plant-based lactic acid bacteria (LAB) to reduce microbiological hazards in kimchi. Cell-free supernatants (CFS) from four LAB strains isolated from kimchi were tested for antimicrobial activity against five foodborne pathogens and two soft-rot pathogens. Each CFS showed antimicrobial activity against both foodborne and soft-rot pathogens. Washing salted kimchi cabbages inoculated with B. cereus with 5% CFS inhibited B. cereus to a greater extent than NaClO. The CFS from WiKim 83 and WiKim 87 exhibits inhibition rates of 25.09% and 24.21%, respectively, compared to the 19.19% rate of NaClO. Additionally, the CFS from WiKim 116 and WiKim 117 showed inhibition rates of 18.74% and 20.03%, respectively. Direct treatment of kimchi cabbage with soft-rot pathogens and CFS for five days inhibited the pathogens with similar efficacy to that of NaClO. To elucidate the antimicrobial activity mechanisms, pH neutralization, heat treatment, and organic acid analyses were performed. pH neutralization reduced the antimicrobial activity, whereas heat treatment did not, indicating that lactic, acetic, citric, and phenyllactic acids contribute to the thermal stability and antimicrobial properties of CFS. This study suggests that the four kimchi-derived LAB, which maintain a low pH through organic acid production, could be viable food preservatives capable of reducing biological hazards in kimchi.

Dermal toxicity studies of 1,2-benzisothiazolin-3-one (CAS number: 2634-33-5) in Sprague-Dawley rats

Biocides are used as preservatives in various household products, and 1,2-benzisothiazolin-3-one (BIT) is one of the popular chemicals. Therefore, BIT is highly likely to be exposed to human skin, necessitating dermal toxicity evaluation. In this study, we aimed to investigate dermal toxicity, eyes and skin irritation, and skin sensitization of BIT. All studies were conducted according to the Organisation for Economic Co-operation and Development testing guidelines. In acute dermal toxicity using rats, no treatment-related responses were observed at the highest dose (2000 mg/kg). A 28-day repeated dermal toxicity study at 1, 4, and 12 mg/kg/day showed transient local skin irritation lesions, including erythema, exfoliation, and crust formation. Based on no systemic effects, the no observed adverse effect level (NOAEL) of BIT of the 28-day repeated dermal toxicity study was determined to be 12 mg/kg/day. Eye and skin irritation tests showed that BIT is a strong irritant and corrosive to the eyes and a mild irritant to the skin. However, BIT showed no skin sensitization reactions in a local lymph node assay. These dermal toxicity studies can provide valuable information for the risk assessment of BIT.

Current frequency of contact allergy to isothiazolinones (methyl-, benz- and octylisothiazolinone) across Europe

BACKGROUND

The use of methylisothiazolinone (MI) as a preservative in cosmetic products caused an alarming increase in MI contact allergy across Europe in the 2010s. This was followed by regulations of use with a total ban on leave-on (implemented in 2017) and reduced use concentrations in rinse-off cosmetics (2018).

OBJECTIVE

To follow-up on the prevalence of contact allergy to MI and the related benzisothiazolinone (BIT) and octylisothiazolinone (OIT) in consecutively patch-tested patients in Europe.

METHODS

A cross-sectional audit following the design of two previous audits on MI contact allergy from 1 May 2022 to 31 October 2022 included all patients patch tested with the European baseline series, including or supplemented with MI, BIT and OIT across 10 departments in eight European countries.

RESULTS

A total of 2554 patients were consecutively patch tested with the three isothiazolinones during the study period. The prevalence of MI and BIT contact allergy was 2.9% (95% confidence interval [CI]: 2.3%-3.7%; range 1.1%-5.8%) and 3.1% (95% CI: 2.4%-3.9%; range 0.0%-6.6%), respectively; that of OIT was 0.7% (95% CI: 0.4%-1.1%; range 0%-3.2%). Rinse-off cosmetic (73.3%) and leave-on cosmetic products (13.3%) were still associated with eliciting allergic contact dermatitis to MI.

CONCLUSION

We confirmed a positive impact of regulatory measures on the prevalence of MI contact allergy in Europe, which halved compared to 2015. However, our data suggest that consumers may still be exposed to older cosmetic products containing MI. BIT has superseded MI in causing contact allergy, despite not being allowed for use in cosmetic products.

Microencapsulation of the Biocide Benzisothiazolinone (BIT) by Inclusion in Methyl-β-cyclodextrin and Screening of Its Antibacterial and Ecotoxicity Properties

The excessive use of biocides has considerable environmental and economic impacts; this is why new technologies have been sought to decrease the concentration levels applied in an effort to reduce the use of these substances. Microencapsulation using cyclodextrins has been widely used in the food and pharmaceutical industries as a way of reducing the concentrations of the active substance necessary to achieve a biological effect and/or eliminate its irritating or toxicological effects. In this study, the inclusion complexation behavior and binding ability of benzothiazolinone (BIT) with different β-cyclodextrins (β-CD, HP-β-CD, and Me-β-CD) was investigated. The intermolecular interactions were examined through UV and FTIR spectroscopy, DSC, 1D 1H NMR, and 2D ROESY. The highest stability constant was observed for the BIT/Me-β-CD inclusion complex (299.5 ± 2.9 M-1). Antibacterial activity was investigated against Staphylococcus aureus and Escherichia coli, and the results revealed that the BIT/Me-β-CD inclusion complex displays a higher antibacterial activity than BIT. The acute toxicity of the biocide and inclusion complex was also examined using the photobacterium Aliivibrio fischeri. Although BIT exhibited higher toxicity than the inclusion complex, further investigation is needed due to the quorum quenching effect of β-CDs. The data found suggest that BIT microencapsulation can increase its aqueous solubility and can be used as an effective tool to improve its chemical, biological, and ecotoxicological properties.

Increasing non-cosmetic exposure and sensitization to isothiazolinones require action for prevention: Review

Frequent use of methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and MI in cosmetic products has been the main cause of widespread sensitization and allergic contact dermatitis to these preservatives (biocides). Their use in non-cosmetic products is also an important source of sensitization. Less is known about sensitization rates and use of benzisothiazolinone (BIT), octylisothiazolinone (OIT), and dichlorooctylisothiazolinone (DCOIT), which have never been permitted in cosmetic products in Europe. BIT and OIT have occasionally been routinely patch-tested. These preservatives are often used together in chemical products and articles. In this study, we review the occurrence of contact allergy to MI, BIT, OIT, and DCOIT over time, based on concomitant patch testing in large studies, and case reports. We review EU legislations, and we discuss the role of industry, regulators, and dermatology in prevention of sensitization and protection of health. The frequency of contact allergy to MI, BIT, and OIT has increased. The frequency of contact allergy to DCOIT is not known because it has seldom been patch-tested. Label information on isothiazolinones in chemical products and articles, irrespective of concentration, is required for assessment of relevance, information to patients, and avoidance of exposure and allergic contact dermatitis.

The new Italian SIDAPA Baseline Series for patch testing (2023): an update according to the new regulatory pathway for contact allergens

Allergic contact dermatitis (ACD) is a common inflammatory skin disease caused by delayed hypersensitivity to chemical and biotic contact allergens. ACD significantly affects the patients' quality of life negatively impacting both occupational and non-occupational settings. Patch testing is the gold standard diagnostic in vivo test to precise the ACD etiology and to correctly perform prevention. According to the Italian Medicines Agency (AIFA) legislative decree no. 178 of 29th May 1991, allergens are defined as medicines and therefore they are subject to strict regulation. In 2017, AIFA (decree no. 2130/2017) started a procedure to regulate contact allergens on the Italian market and actually the contact allergens temporarily authorized are reported in AIFA decree no. 98/2022, valid until November 2023. The availability on the market of contact allergens to diagnose ACD and continuous updating on the basis of new epidemiological trends are mandatory, jointly with the continuous update of the baseline and integrative series for patch testing. For this reason, the scientific community represented in Italy by the Skin Allergies Study Group of SIDeMaST (Italian Society of Dermatology and Venereology) and SIDAPA (Italian Society of Allergological, Occupational and Environmental Dermatology) are constantly working, in close relationship with the European scientific communities with large expertise in this important sector of the modern Dermatology. Herein, we report the setting up of regulatory legislation by AIFA and the new Italian Adult Baseline Series for patch testing.

Analysis of Contact Allergens in Polyvinyl Chloride Examination Gloves in the United States

Background: Polyvinyl chloride (PVC) gloves are recommended as a safe alternative for patients with rubber accelerator allergy. However, allergic contact dermatitis to other chemicals in PVC gloves has been reported. Objective: To analyze single-use PVC medical examination gloves in the United States for the presence of potential contact allergens. Methods: Using liquid chromatography-mass spectrometry, 20 unique PVC gloves were analyzed in triplicate for 6 chemicals: benzisothiazolinone, bisphenol A, mono(2-ethylhexyl) maleate, tricresyl phosphate, triphenyl phosphate, and triphenyl phosphite. Results: All 20 PVC gloves contained detectable quantities of benzisothiazolinone (range, 0.001-1.48 parts per million [ppm]), bisphenol A (0.01-0.11 ppm), triphenyl phosphate (0.01-2.11 ppm), and triphenyl phosphite (0.001-0.22 ppm). Eighteen (90%) gloves contained mono(2-ethylhexyl) maleate (0.001-0.14 ppm) and 3 (15%) contained tricresyl phosphate (0.001-0.002 ppm). Conclusions: Known allergens were present in all 20 PVC gloves. However, the detected levels were mostly low and their relationship with sensitization and elicitation thresholds requires further study.

More than just methylisothiazolinone: Retrospective analysis of patients with isothiazolinone allergy in North America, 2017-2020

BACKGROUND

Isothiazolinones are a common cause of allergic contact dermatitis.

OBJECTIVE

To examine the prevalence of positive patch test reactions to isothiazolinones from 2017-2020 and characterize isothiazolinone-allergic (Is+) patients compared with isothiazolinone nonallergic (Is-) patients.

METHODS

Retrospective cross-sectional analysis of 9028 patients patch tested to methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI) 0.02% aqueous, MI 0.2% aqueous, benzisothiazolinone (BIT) 0.1% petrolatum, and/or octylisothiazolinone (OIT) 0.025% petrolatum. Prevalence, reaction strength, concurrent reactions, clinical relevance, and source of allergens were tabulated.

RESULTS

In total, 21.9% (1976/9028) of patients had a positive reaction to 1 or more isothiazolinones. Positivity to MI was 14.4% (1296/9012), MCI/MI was 10.0% (903/9017), BIT was 8.6% (777/9018), and OIT was 05% (49/9028). Compared with Is-, Is+ patients were more likely to have occupational skin disease (16.5% vs 10.3%, P <.001), primary hand dermatitis (30.2% vs 19.7%, P <.001), and be >40 years (73.1% vs 61.9%, P <.001). Positive patch test reactions to >1 isothiazolinone occurred in 44.1% (871/1976) of Is+ patients. Testing solely to MCI/MI would miss 47.3% (611/1292) of MI and 60.1% (466/776) of BIT allergic reactions.

LIMITATIONS

Retrospective cross-sectional study design and lack of follow-up data.

CONCLUSION

Sensitization to isothiazolinones is high and concurrent sensitization to multiple isothiazolinone allergens is common.

Contact sensitization to benzisothiazolinone: IVDK-data of the years 2002 to 2021

BACKGROUND

Benzisothiazolinone (BIT; CAS no. 2634-33-5) is used as a biocide in various products, including water-based paints, metalworking fluids, and household products. In recent years, increasing sensitization rates have been observed in Europe.

OBJECTIVE

To describe a time trend of sensitization to BIT, analyse concomitant reactions, and identify patients with increased risk of BIT sensitization.

METHODS

Retrospective analysis of data from 26 739 patients patch tested with BIT, sodium salt, 0.1% petrolatum as part of several special test series within the Information Network of Departments of Dermatology (IVDK), 2002 to 2021.

RESULTS

Positive reactions to BIT were noted in 771 patients (2.9%). Sensitization frequency varied over time and increased in recent years, peaking at 6.5% in 2020. Painters and metalworkers handling metalworking fluids, but not cleaners, had a significantly increased risk of BIT sensitization. From our data, there is no evidence of immunological cross-reactivity between BIT and other isothiazolinones.

CONCLUSION

The increasing frequency of sensitization justifies adding BIT to the baseline series. More research on the clinical relevance of positive patch test reactions to BIT and the cause for the rising numbers of BIT sensitization is needed.

HIGHLIGHTS

Frequency of sensitization to BIT has increased in recent years. The increasing frequency of sensitization justifies adding BIT to the baseline series. Painters and metalworkers handling metalworking fluids, but not cleaners, has a significantly increased risk of BIT sensitization. We found no evidence of immunological cross-reactivity between BIT and other isothiazolinones.

Sensitization to isothiazolinones in the Spanish Contact Dermatitis Registry (REIDAC): 2019-2021 epidemiological situation

BACKGROUND

Current frequency and risk factors for sensitization to methylisothiazolinone (MI), methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), benzisothiazolinone (BIT) and octylisothiazolinone (OIT) in Spain are not well known.

OBJECTIVES

To study the frequency of sensitization, risk factors and simultaneous sensitization between the four isothiazolinones.

MATERIALS AND METHODS

We analysed all 2019-2021 consecutive patients patch-tested with MI (0.2% aq.), MCI/MI (0.02% aq.), BIT (0.1% pet.) and OIT (0.1% pet) within the Spanish Contact Dermatitis Registry (REIDAC).

RESULTS

A total of 2511 patients were analysed. Frequencies of sensitization were: any isothiazolinone 15.7%, MI 6.8%, MCI/MI 4.8%, BIT 3.5% and OIT 0.5%. MI and MCI/MI sensitization was associated with being occupationally active, hand dermatitis, detergents and age over 40. BIT sensitization was associated with leg dermatitis and age over 40. About one in nine MI-positive patients were positive to BIT, whereas one in five BIT-positive patients were positive to MI.

CONCLUSIONS

Sensitization to MI, MCI/MI and BIT is still common in Spain, while sensitization to OIT is rare. Currently, sensitization to MI and MCI/MI seems to be occupationally related. Although its origin is unknown, sensitization to BIT is more frequent in patients aged over 40 years. Simultaneous sensitization between MI and BIT is uncommon.

North American Contact Dermatitis Group Patch Test Results: 2019-2020

Background: Patch testing is an important diagnostic tool for assessment of allergic contact dermatitis (ACD). Objective: This study documents the North American Contact Dermatitis Group (NACDG) patch testing results from January 1, 2019, to December 31, 2020. Methods: At 13 centers in North America, patients were tested in a standardized manner with a screening series of 80 allergens, and, as indicated, supplemental allergens. Results: Overall, 4121 patients were tested; 2871 (69.7%) had at least 1 positive/allergic patch test reaction and 2095 patients (51.2%) had a primary diagnosis of ACD. The most commonly positive allergens were nickel (18.2%), methylisothiazolinone (MI) (13.8%), fragrance mix (FM) I (12.8%), hydroperoxides of linalool (HPL) (11.1%), and benzisothiazolinone (BIT) (10.4%). Compared with that of 2017-2018, prevalence of top 20 allergens statistically increased for FM I, HPL, BIT, propolis, and hydroperoxides of limonene (3.5%). For the first time, MI positivity did not increase between reporting periods. Approximately one-fifth of patients (20.3%) had ≥1 clinically relevant reaction(s) to allergens/substances not on the NACDG series. Conclusions: The epidemic of MI contact allergy in North America may have reached a plateau. Patch testing using a robust screening series, and supplemental allergens as indicated, is necessary for comprehensive evaluation of ACD.

Hypersensitivity to permanent tattoos: Literature summary and comprehensive review of patch tested tattoo patients 1997-2022

We outline constituents of tattoo and permanent make-up ink with regard to inflammatory tattoo reactions and population-based confounders. The comprehensive review of patch-tested tattoo patients between 1997 and 2022 shows that tattoo allergy cannot be reliably diagnosed via patch testing with today's knowledge. Weak penetration and slow haptenization of pigments, unavailability of pigments as test allergens and a lack of knowledge concerning relevant epitopes hamper the diagnosis of tattoo allergy. Patch testing p-phenylenediamine and disperse (textile) dyes is not able to close this gap. Sensitization to metals was associated with all types of tattoo complications, although often not clinically relevant for the tattoo reaction. Binders and industrial biocides are frequently missing on ink declarations and should be patch tested. The pigment carbon black (C.I. 77266) is no skin sensitizer. Patch tests with culprit inks were usually positive with cheap ink products for non-professional use or with professionally used inks in patients with eczematous reactions characterized by papules and infiltration. Tape stripping before patch testing and patch test readings on Day 8 or 10 may improve the diagnostic quality. The meaningfulness of the categorical EU-wide ban of Pigment Green 7 and Pigment Blue 15:3 is not substantiated by the presented data.

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.

Occurrence of Allergens in Cosmetics for Sensitive Skin

Sensitive skin is characterized by symptoms such as stinging and tingling in response to stimuli that usually do not cause unpleasant sensations. Epidemiological studies show that individuals with sensitive skin are more prone to developing skin allergies, although the link between both conditions is unknown. Aiming to evaluate the presence of allergens in facial-skin products for sensitive skin, a pool of 88 cosmetic products from international brands marketed in pharmacies and parapharmacies was analyzed. A list of allergens identified in product labels was compiled and grouped according to their function. Fragrances were the most common allergens, followed by skin-conditioning agents, surfactants, and preservatives. Fragrances presenting the highest use percentages were linalool, benzyl alcohol, geraniol, and citronellol. Overall, the majority of cosmetic formulations were absent of fragrance allergens, being present only in 7% of products. Other allergens were found in most products (95%). This finding should be interpreted with caution, since many of these compounds are rare sensitizers and studies demonstrating their risk for individuals with sensitive skin are lacking. With this study, useful information for health professionals is provided to support their advice and to help consumers choosing cosmetic products.

Novel insights into contact dermatitis

Contact dermatitis is a common disease, caused by repeated skin contact to contact allergens or irritants, resulting in allergic contact dermatitis (ACD) and/or irritant contact dermatitis. Attempts have been made to identify biomarkers to distinguish irritant and allergic patch test reactions, which could aid diagnosis. Some promising candidates have recently been identified, but verification and validation in clinical cases still need to be done. New causes of ACD are constantly recognized. In this review, 10 new contact allergens from recent years, were identified, several relating to anti-age products. Frequent allergens causing considerable morbidity in the population such as the preservative methylisothiazolinone (MI) have been regulated in EU. A significant drop in cases has been seen, while high rates are still occurring in other areas such as North America. Other frequent causes are fragrance allergens especially widely used terpenes and acrylates used in medical devises for control of diabetes. These represent unsolved problems. Recent advances in immunology have opened for a better understanding of the complexity of contact dermatitis, especially ACD. The disease may be more heterogenous that previous understood with several subtypes. With the rapidly evolving molecular understanding of the disease, the potential for development of new drugs for personalized treatment of contact dermatitis is considerable.

European patch test results with audit allergens as candidates for inclusion in the European Baseline Series, 2019/20 - Joint results of the ESSCAA and the EBSB working groups of the ESCD, and the GEIDACC

BACKGROUND

In 2019, a number of allergens (haptens), henceforth, 'the audit allergens,' were considered as potential additions to the European baseline series (EBS), namely, sodium metabisulfite, 2-bromo-2-nitropropane-1,3-diol, diazolidinyl urea, imidazolidinyl urea, Compositae mix II (2.5 or 5% pet), linalool hydroperoxides (lin-OOH), limonene hydroperoxides (lim-OOH), benzisothiazolinone (BIT), octylisothiazolinone (OIT), decyl glucoside, lauryl glucoside; Evernia furfuracea (tree moss), was additionally tested by some departments, too.

OBJECTIVES

To collect further data on patch test reactivity and clinical relevance of the audit allergens in consecutive patients across Europe.

METHODS

Patch test data covering the audit allergens in 2019 and 2020 were collected by those departments of the ESSCA testing these, as well as further collaborators from the EBS working group of the ESCD, and the Spanish GEIDAC. As patch test outcome, reactions between day (D) 3 and D5 were considered.

RESULTS

Altogether n=12403 patients were tested with any of the audit allergen. Positive reactions were most common to lin-OOH 1% pet. (8.74 (8.14-9.37)), followed by lin-OOH 0.5% pet., and lim-OOH 0.3% pet (5.41 (4.95-5.89)). Beyond these terpene hydroperoxides, BIT 0.1% pet. was the second most common allergen with 4.72 (4.2-5.28), followed by sodium metabisulfite 1% pet. (3.75 (3.32-4.23)) and Compositae mix 5% pet. (2.31 (1.84-2.87). For some allergens, clinical relevance was frequently difficult to ascertain.

CONCLUSIONS

Despite many positive patch test reactions, it remains controversial whether lin- and lim-OOH should be tested routinely, while at least the two preservatives BIT and sodium metabisulfite appear suitable. The present results are a basis for further discussion among the ESCD members and ultimately decision on their implementation into routine testing. This article is protected by copyright. All rights reserved.