Methylisothiazolinone, an emerging allergen in cosmetics?

Methylisothiazolinone sensitisation in New Zealand is decreasing

BACKGROUND/OBJECTIVES

In the last 10 years methylisothiazolinone (MI) emerged as a global cause of preservative-related ACD. New Zealand has liberal regulations for the MI concentration limit in cosmetic products compared to Europe and Australia. The aim of this study was to evaluate the prevalence of MI sensitisation in New Zealand, explore sources of MI exposure and make recommendations on New Zealand regulations for MI use.

METHODS

This retrospective study included data from patients who underwent patch testing with MI from 2008 to 2021 in a tertiary hospital dermatology clinic and a private dermatology clinic in Auckland, New Zealand. Patient baseline characteristics were recorded along with results of patch testing. Sources of MI exposure were identified from medical records.

RESULTS

Over the study period, 1049 patch tests were performed in 1044 patients. MI was only tested as a stand-alone allergen from 2015; positive reactions to MI increased from 5.3% in 2015 to a peak of 11.9% in 2017 and then decreased to 6.4% in 2021. The most common source of MI exposure was shampoo or conditioner (27.7% of all relevant reactions) followed by occupational exposures to paints, biocides or glue (19.1%).

CONCLUSION

Both sensitisation and ACD to MI appear to be decreasing, likely secondary to changes in product compounding due to stricter concentration limits internationally. We recommend New Zealand adopt lower MI concentration limits for cosmetics to match the limits of Australia and Europe.

Target and Suspect Screening for Organic Additives in Six Classifications of Personal Care Products Using Liquid Chromatography-High-Resolution Mass Spectrometry

Personal care products (PCPs) are integral components of daily human existence, including a large number of chemicals intentionally added for functional attributes (e.g., preservatives and fragrances) or unintentionally present, such as plasticizers. This investigation aimed to optimize the methodology for target and suspect screening via liquid chromatography-high-resolution mass spectrometry, focusing on nine prevalent organic additives (comprising bisphenols A, F, and S, methyl, ethyl, propyl, and butylparaben, 5-chloro-2-methyl-4-isothiazolin-3-one, and 4-hydroxybenzoic acid). A total of 50 high-selling PCPs were purchased from the local online market as samples. In detail, PCP samples were classified into body washes, shampoos, hair conditioners, facial cleansers, body lotions, and moisture creams. For calibration, the quality assurance and quality control results demonstrated a coefficient of determination (R2) surpassing 0.999, with detection and quantification limits ranging from 2.5 to 100.0 ng/g. For recovery experiments, replicate recoveries (n = 5) ranged from 61 to 134%. In purchased PCP samples, five of the nine target compounds were detected via a target screening. Methylparaben exhibited the highest concentration (7860 mg/kg) in a facial cleanser, which is known as an endocrine-disrupting chemical. A total of 248 suspects of organic additives were screened in PCPs, leading to a tentative identification of 9. Confirmation (confidence level 1) via reference standards was achieved for three suspects, while six were tentatively identified with a confidence level of 2. This two-step extraction methodology utilizing methyl tert-butyl ether and isopropyl alcohol enabled simultaneous analysis of diverse chemical groups with distinct properties.

From skin sensitizers to wastewater: the unknown photo-deactivation process of low-lying excited states of isothiazolinones. A non-adiabatic dynamics investigation

Isothiazolinones represent a class of heterocyclic compounds widely used in various applications, including as biocides in cosmetics, detergents, and paints, as well as in industrial wastewater treatment. Indeed, the presence of isothiazolinones in the environment and their associated potential health hazards have raised significant concerns. In this study, a non-adiabatic dynamics investigation was conducted using state-of-the-art methodologies to explore the photochemistry of isothiazolinones. A simplified model, isothiazol-3(2H)-one (ISO), was employed to represent this compound class. The study validated the model and demonstrated that ISO can return to its ground state through the cleavage of the S-N or S-C bonds, with no significant energy barrier observed. Non-adiabatic dynamics simulations provided insights into the time scales and detailed processes of isothiazolinone photodissociation. The preferred route for deactivation was found to be the cleavage of the S-N bond. This research enhances our understanding of the photodeactivation processes of isothiazolinones and their potential environmental impact.

Cosmetic preservative labelling in philippine products in accordance with philippine regulations

BACKGROUND

Preservatives are usually added to a wide array of consumer products to prevent growth of microbes and to prevent product destabilization and degradation. However, many of these preservatives are common skin sensitizers and may cause allergic contact dermatitis. The amount of preservatives may vary per country or region according to their respective legislation, and may be reported in differences in prevalence rates of contact dermatitis.

OBJECTIVE

To examine and identify preservatives in consumer products in accordance with Philippine legislation. To verify the accuracy of the list of ingredients of Philippine cosmetic products as legislated by the Philippine Bureau of Food and Drug Administration.

METHODS

A total of 65 commonly used Philippine consumer products ranging from liquid facial and body washes, bar soaps, laundry detergents, feminine hygiene washes and wipes, shampoos and conditioners, sunblock, and moisturizers were selected. Ingredients noted on labels were documented. Products were subsequently investigated chemically for the presence of either methylchloroisothiazolinone, methylisothiazolinone, and formaldehyde.

RESULTS

The preservatives most commonly used in cosmetic products in the Philippine market are: methylchloroisothiazolinone (MCI), methylisothiazolinone (MI), and/or formaldehyde. In accordance with Philippine legislation, almost all products provided a detailed ingredient list as printed on the packaging. Measurements of MCI/MI ranged from less than 1 ppm to 16 ppm, and MI only ranged from less than 1 ppm to 66 ppm, whereas formaldehyde was noted to range from less than 2.5 ppm to greater than 40 ppm in the products tested. Most products are manufactured by international brands with a few products being manufactured locally.

CONCLUSIONS

The preservatives found in cosmetic products were MCI, MI and formaldehyde. There were discrepancies found in the preservatives and labelling of these products, with a majority of investigated Philippine products labelled inaccurately with varying concentrations of preservatives. This article is protected by copyright. All rights reserved.

Evolution of methylisothiazolinone sensitization: a Belgian multicentric study from 2014 to 2019

BACKGROUND

In the 2010s an epidemic of allergic contact dermatitis to methylisothiazolinone occurred in Europe. European authorities banned the use of methylisothiazolinone in leave-on cosmetics in 2017 and limited its use in rinse-off products in 2018.

OBJECTIVES

To investigate the sensitization rate to methylisothiazolinone in Belgium between January 2014 and December 2019, and to assess co-sensitizations to octylisothiazolinone and benzisothiazolinone in methylisothiazolinone -sensitized patients.

METHODS

A retrospective study of patch test results with methylisothiazolinone, octylisothiazolinone and benzisothiazolinone observed in patients attending five Belgian hospitals.

RESULTS

Overall, 560 of 10.029 patients (5.58%) had a positive patch test reaction to methylisothiazolinone, and its sensitization rate decreased from 7.9% in 2014 to 3.1% in 2019. Rinse-off cosmetics, paints and detergents were the most prevalent sensitization sources in recent years. Simultaneous reactions readily occurred to octylisothiazolinone, and, surprisingly, and increasingly, also to benzisothiazolinone.

CONCLUSIONS

Contact allergy to methylisothiazolinone in Belgium has reached a pre-epidemic level, reflecting the impact of recent regulatory measures. Leave-on cosmetics, in contrast to rinse-off products, have almost disappeared as sensitization sources in Europe. Paints and detergents also remain problematic. The remarkably high number of patients (co-) sensitized to benzisothiazolinone should be a focus of future research. This article is protected by copyright. All rights reserved.

Epidemics of Dermatitis

Allergic contact dermatitis (ACD) remains a globally prevalent disease for both children and adults. The silent ACD epidemic continues to be fueled by the introduction of novel allergens in industrial and household products and the continued presence of known allergens. In 1997, Allan Dillarstone noted a sinusoidal pattern to epidemics when allergenic preservatives were replaced by alternative chemicals within the market, which then similarly increased in allergenicity. A call for public health vigilance and prevention initiatives is needed to intervene in the ACD epidemic.

Patch Testing With Methylchloroisothiazolinone/Methylisothiazolinone Using a New Diagnostic Mix-A Multicenter Study From the International Contact Dermatitis Research Group

BACKGROUND

In the early 1980s, a preservative containing a mixture of methylchloroisothiazolinone (MCI) and methylisothiazolinone (MI) in a ratio of 3:1 was introduced. This mixture (mix) has been patch tested at 100 ppm (0.01%) worldwide and at 200 ppm (0.02%) in Sweden since 1986 and also in the European baseline series since 2014.

OBJECTIVE

A new aqueous mix of MCI 0.015% and MI 0.2% was compared with patch testing with the 2 aqueous baseline preparations of MCI/MI 0.02% and MI 0.2%.

METHODS

Four thousand three hundred ninety-seven patients with dermatitis in 12 International Contact Dermatitis Research Group dermatology departments from 3 continents were patch tested simultaneously with the 3 preparations.

RESULTS

The frequency of positive patch tests to the allergens varied between 0% and 26.7% in the 12 test centers. The new mixture MCI/MI 0.215% in aqua (aq) detected significantly more patients with MCI/MI allergy than both MCI/MI 0.02% aq (P < 0.001) and MI 0.2% aq (P < 0.001) alone and combined.

CONCLUSIONS

The results favor replacing the preparations MCI/MI 0.02% aq and MI 0.2% aq with the mixture MCI/MI 0.215% aq in the International Contact Dermatitis Research Group baseline series.

Contact allergen sensitivity in children with contact dermatitis

Objective

Irritant contact dermatitis and Allergic contact dermatitis are two distinct forms of contact dermatitis. Allergic contact dermatitis is a Type 4 (delayed-type) hypersensitivity reaction that occurs during subsequent contact with an allergen to a previously sensitized person. The number of allergens that cause allergic contact dermatitis is increasing day by day. Although it is not the gold standard for the detection of these allergens, skin patch testing is a very helpful method. This study aimed to determine the most common contact allergens in the pediatric age group.

Material and Methods

All patients with the diagnosis of contact dermatitis who underwent a skin patch test (TRUE TEST) in the department of Pediatric Allergy and Immunology between March 2017-February 2018 were enrolled in this study. The patch test was evaluated 72 hours later by the same physician and interpreted as recommended by the American Academy of Dermatology. In addition to the patient files, demographic and clinical characteristics, localization of lesions, and itch score according to visual analog scale were recorded.

Results

A total of 80 children enrolled in the study; 45 (56.3%) were girls and 35 (43.7%) were boys. The mean age of the children was 7.37±3.84 years and 57.5% of the patients who underwent skin patch testing had a positive response to at least one or more allergens. The most common allergens were Nickel sulfate, CI + Me-Isothiazolinone, Thiuram Mix, Formaldehyde, and P-tert-butylphenol formaldehyde resin (14.8%, 10%, 6.3%). There was no difference in terms of age, sex, duration of complaints, and pruritus score according to nickel sensitization.

Conclusion

In the presence of chronic dermatitis in children, allergic contact dermatitis should be considered in the differential diagnosis. The culprit allergen should be determined. Also, the most common contact allergen is Nickel Sulphate in the world and the increased sensitization to other allergens is due to the increased contact of children with cosmetics and different contact allergens.

The epidemic of contact allergy to methylisothiazolinone-An analysis of Danish consecutive patients patch tested between 2005 and 2019

BACKGROUND

In 2005, methylisothiazolinone (MI) was allowed as a stand-alone preservative in cosmetics. This resulted in an epidemic of allergic contact dermatitis to MI, mainly affecting women exposed to leave-on cosmetics. Consequently, a regulation of Annex V in the European Union in 2017 banned the use of MI in leave-on cosmetics and reduced the allowed concentration in rinse-off products.

OBJECTIVE

To analyze the temporal trends in contact allergy to MI in Danish patients in relation to key events including European regulations over time.

METHODS

A retrospective study of consecutive patients patch tested with methylisothiazolinone from 2005 to 2019. Demographics and clinical characteristics in terms of MOAHLFA (male, occupational, atopic dermatitis, hand dermatitis, leg dermatitis, facial dermatitis and age >40 years), sources of exposure, and clinical relevance were analyzed in relation to key historical events.

RESULTS

Three hundred eighty of 12 494 patients (3.0%, 95CI: 2.7-3.4%) tested from 2005 to 2019 were sensitized to MI. An increasing trend in the prevalence of MI contact allergy from 2005 to 2019 (P < .01) was observed, although a decline in the absolute number of patch-test positive patients was seen from 2013 and onward. A reduction in leave-on cosmetics as a source of exposure was observed following the legislative ban in 2017, from 24.8% from in 2010 to 2013 to 6.2% in 2017 to 2019 (P < .01).

CONCLUSION

The epidemic of MI contact allergy is declining in absolute terms, although the prevalence in the patch-tested population has not returned to its pre-epidemic levels. The legislative regulation of MI in 2017 has been effective in terms of leave-on cosmetics as a source of exposure in MI allergic patients. The process of post-marketing risk assessment of contact allergens in the European Union needs improvement.

Occurrence of methylisothiazolinone in water and soil samples in Poland and its biodegradation by Phanerochaete chrysosporium

Methylisothiazolinone is a commonly used biocide that is released into natural environments. In this work, the ability of the fungal strain Phanerochaete chrysosporium DSM 1556 to biotransform this compound was evaluated. The tested strain was able to remove MIT (at concentrations 50 μg L^-1 and 30 mg L^-1) from the growth medium with the efficiency 90% after the first 6 h and 100% after 12 h of incubation. Moreover, for the first time, qualitative LC-MS/MS and GC-MS analysis showed monohydroxylated and dihydroxylated methylisothiazolinone and N-methylmalonamic acid as the main products of fungal biodegradation. The ecological toxicity of the tested biocide and its derivatives was also evaluated by using an acute toxicity test with Daphnia magna. An approximately 90% decrease in the toxicity of metabolites formed in the P. chrysosporium culture was noticed. The concentration of MIT in soil and water samples collected in Poland was assessed for the first time. The analysis showed that the selected locations in Poland are contaminated by MIT in the range from 1.04-10.08 μg L^-1.

Methylchloroisothiazolinone/methylisothiazolinone and methylisothiazolinone contact allergy: A 24-year, single-center, retrospective cohort study from Turkey

BACKGROUND

Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and MI allergy caused a global epidemic during the period 2010 to 2015, reaching its peak in 2013/14.

OBJECTIVE

To investigate the characteristics of MCI/MI and MI allergy in Turkey over 24 years.

METHODS

A total of 2310 patients patch tested between 1996 and 2019 with MCI/MI 0.01% aq. or MCI/MI 0.02% aq., with or without MI 0.2% aq., were analyzed.

RESULTS

The overall prevalence of contact sensitization was 3.3% (n = 77) with a peak level of 16.4% in 2015. The prevalence gradually decreased thereafter, but was still high (6.5%) in 2019. Seventy-three patients had clinically relevant sensitizations. MI could detect clinically relevant sensitizations in all seven patients with a negative patch test reaction to MCI/MI 0.02%. Non-occupational allergic contact dermatitis (ACD) was most frequently seen, mainly in women, with hand/face eczema from rinse-off or leave-on cosmetics, such as wet wipes. Occupational ACD was mainly seen among men with airborne eczema from wall paints in house painters, or with hand eczema from hair gel/wax in men's barbers.

CONCLUSIONS

The prevalence of MCI/MI and MI sensitization in Turkey following the peak in 2015 is still high. This is probably due to the currently allowed level of 100 ppm for MI in rinse-off cosmetics. This needs to be urgently reduced.

Eyelid dermatitis in patients referred for patch testing: Retrospective analysis of North American Contact Dermatitis Group data, 1994-2016

BACKGROUND

Eyelid dermatitis is a common dermatologic complaint.

OBJECTIVE

To characterize patients with eyelid dermatitis.

METHODS

Retrospective analysis (1994-2016) of North American Contact Dermatitis Group data.

RESULTS

Of 50,795 patients, 2332 (4.6%) had eyelid dermatitis only, whereas 1623 (3.2%) also had dermatitis of the eyelids and head or neck. Compared with patients without eyelid involvement (n = 26,130), groups with eyelid dermatitis only and dermatitis of the eyelid and head or neck were significantly more likely to be female, white, and older than 40 years, and to have a history of hay fever, atopic dermatitis, or both (P < .01). Final primary diagnoses included allergic contact dermatitis (eyelid dermatitis only: 43.4%; dermatitis of the eyelid and head or neck: 53.5%), irritant contact dermatitis (eyelid dermatitis only: 17.0%; dermatitis of the eyelid and head or neck: 9.8%), and atopic dermatitis (eyelid dermatitis only: 13.1%; dermatitis of the eyelid and head or neck: 13.8%). Top 5 currently relevant allergens included nickel sulfate (eyelid dermatitis only: 18.6%; dermatitis of the eyelid and head or neck: 22.5%), fragrance mix I (eyelid dermatitis only: 16.5%; dermatitis of the eyelid and head or neck: 18.3%), methylisothiazolinone (eyelid dermatitis only: 16.5%; dermatitis of the eyelid and head or neck: 17.7%), gold sodium thiosulfate (eyelid dermatitis only: 14.7%; dermatitis of the eyelid and head or neck: 11.4%), and balsam of Peru (eyelid dermatitis only: 11.9%; dermatitis of the eyelid and head or neck: 12.6%). Both eyelid-involvement groups were significantly more likely to react to gold sodium thiosulfate, carmine, shellac, dimethylaminopropylamine, oleamidopropyl dimethylamine, and thimerosal (P < .05) compared with the no eyelid involvement group.

LIMITATIONS

Lack of specific distribution patterns of eyelid dermatitis and no long-term follow-up data.

CONCLUSION

Patch testing remains a critical tool in evaluating patients with eyelid dermatitis.

Effects of chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT) on Th2/Th17-related immune modulation in an atopic dermatitis mouse model

Exposure to chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT) has been associated with allergic contact dermatitis and occupational asthma. Despite this association however, no study has investigated the effects of CMIT/MIT exposure on the development of atopic dermatitis (AD). This study was conducted to investigate the influence of epicutaneous exposure to CMIT/MIT on AD in a mouse model and the underlying biological mechanisms. BALB/C mice were exposed to CMIT/MIT for 3 weeks and AD was developed using ovalbumin (OVA) epidermal sensitization. CMIT/MIT epicutaneous exposure in normal mice significantly enhanced AD-like phenotypes (e.g., transepidermal water loss, clinical score, total serum immunoglobulin E level and infiltration of inflammatory cells). In addition, CMIT/MIT exposure significantly augmented the mRNA expression level of T helper (Th) 2-related cytokines (thymic stromal lymphopoietin, interleukin (IL)-6 and IL-13), Th2 chemokine (chemokine (C-C motif) ligand 17) and the population of CD4⁺IL-4⁺ cells in the skin. Moreover, mice exposed to CMIT/MIT in the OVA challenge had greater AD-like phenotypes, higher IL-4 and IL-17A skin mRNA expression levels, and a larger population of CD4⁺IL-4⁺- and IL-17A⁺-producing cells in the skin-draining lymph nodes. Our current findings in a mouse model thus suggest that CMIT/MIT exposure may cause AD symptoms through the dysregulation of Th2/Th17-related immune responses.

Patch test in Chinese in Shanghai with cosmetic allergy to cosmetic series and products

BACKGROUND

There are increasing cosmetic adverse reactions in China, mostly cosmetic contact dermatitis, with the development of its cosmetics industry.

AIMS

To identify the allergens and cosmetics products responsible for cosmetic allergic contact dermatitis (CACD) in Shanghai.

METHODS

Five hundred and sixty patients, including 342 suspected CACD patients from dermatological clinic and 218 cosmetics consumers with an allergic history, were patch tested with a cosmetic series (C-1000 series). And 154 patients patched with possible culprit cosmetics.

RESULTS

Two hundred and forty-six subjects showed positive reaction to C-1000 series. Clinic patients had much higher positive rate than that of cosmetics consumers. Leading allergens were methylisothiazolinone (MI), methylisothiazolinone + methylchloro-isothiazolinone (MCI/MI), thimerosal, and the positive rates were significantly higher in patients than in cosmetic consumers (P < .001 for all). MCI/MI elicited positive patch test reactions in 73.5% of MI-positive patients. Of those patched with cosmetic products, 19 patients had 31 positive reactions, including 22 skin care products and 5 color decorating.

CONCLUSIONS

Preservatives, especially MI, MCI/MI, and thimerosal, were the most common cosmetic allergens, and skin care products occupied the most allergic reaction of CACD. Patch testing is highly recommended for suspected CACD patients. Future comparative investigation with large sample size should benefit cosmetovigilance surveillance.

Trend of relevant contact allergens of the feet in Spain over a period of 10 years

INTRODUCTION

Allergic contact dermatitis (ACD) of the feet accounts for approximately 10% of all patch tested patients.

OBJECTIVE

To study the clinical profile of patients with feet dermatitis and relevant contact allergens in Spain over a 10-year period.

METHODS

Retrospective observational study of patients with suspected ACD from the GEIDAC (Spanish Research Group on Contact Dermatitis and Cutaneous Allergy) baseline series from eight hospitals in Spain between 2004 and 2014. The clinical data collected from each patient were age, sex, occupation, history of atopic dermatitis, and eczema location.

RESULTS

A total of 450 cases clinically presented dermatitis affecting the feet; of these, 41% of were males and 5.6% were suspected to be of occupational origin. As much as 47% were diagnosed with ACD, 20% with atopic dermatitis/dyshidrotic eczema, and 5% with psoriasis. The "feet group" included statistically significantly more females in the age range of 21 to 60 years. The most frequent relevant contact allergens were potassium dichromate, cobalt(II) chloride, p-tert-butylphenol formaldehyde resin, mercapto mix, and mercaptobenzothiazole.

CONCLUSIONS

ACD is the most frequent clinical diagnosis of feet dermatitis in our series. The most frequent allergens are similar to those published in other series of foot ACD in Europe and the trend has not changed in the studied decade.

Amended Safety Assessment of Methylisothiazolinone as Used in Cosmetics

The Cosmetic Ingredient Review Expert Panel (Panel) reviewed the safety of methylisothiazolinone (MI), which functions as a preservative. The Panel reviewed relevant animal and human data provided in this safety assessment and in a previously published safety assessment of MI and concluded that MI is safe for use in rinse-off cosmetic products at concentrations up to 100 ppm and safe in leave-on cosmetic products when they are formulated to be nonsensitizing, which may be determined based on a quantitative risk assessment.

Isothiazolinone derivatives and allergic contact dermatitis: a review and update

Allergic contact dermatitis (ACD) from isothiazolinones has frequently been described in the literature. Following an epidemic of sensitization to methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) in the 1980s, and more recently to MI, the Scientific Committee on Consumer Safety of the European Commission banned their use in leave-on products, while restricting that in rinse-off cosmetics. Despite a decreasing prevalence of ACD from MCI/MI and MI, cases caused by occupational exposure and non-cosmetic isothiazolinone sources are on the rise. Moreover, sensitization to newer and lesser known isothiazolinones has been reported. This paper reviews the epidemiology of contact allergy to different isothiazolinones, clinical presentation of isothiazolinone-induced ACD, most relevant sensitization sources and potential cross-reactions between isothiazolinone derivatives. It also provides an update on recent legislative measures.

Perianal Dermatitis

BACKGROUND

Perianal complaints are often consulted in dermatology clinics, and in many cases, a conclusive diagnosis is not easily made.

OBJECTIVE

The aim of this study was to study and identify the epidemiological, clinical, and contact allergy features of patients with perianal dermatitis who attended at a contact dermatitis unit in a tertiary hospital in Spain.

METHODS

Adult patients with long-lasting (>4 weeks) perianal dermatitis were recruited during the past 10 years for investigation and follow-up. Every patient underwent a diagnostic workup consisting of dermatological exploration and patch tests with the standard and specific series, as well as the patients' own products. General surgical exploration was also performed in some patients.

RESULTS

One hundred twenty-four patients were included. The MOAHLFA index was as follows: 43.5, 0, 4.8, 11.3, 1.6, 8.1, and 75. The main final diagnoses were allergic contact dermatitis (32.3%), psoriasis (24.2%), irritant contact dermatitis (17.7%), and lichen simplex (neurodermatitis) (10%). Eighty-one patients (66.1%) showed 1 or more positive reactions, and in 52 patients (43%), positive reactions relevant to the present disease were found.

CONCLUSIONS

Contact allergy in patients with long-lasting perianal complaints is frequent. It is mandatory for these patients to be referred to a dermatologist for an adequate evaluation and patch testing. Methylchloroisothiazolinone/methylisothiazolinone seems as the most common allergen implicated in perianal contact dermatitis.

Effects of a mixture of chloromethylisothiazolinone and methylisothiazolinone on peripheral airway dysfunction in children

BACKGROUND

Children who were only exposed to a mixture of chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) as humidifier disinfectant (HD) components were evaluated for humidifier disinfectant-associated lung injury (HDLI) from 2012. This study was to evaluate the pulmonary function using, impulse oscillometry (IOS) for children exposed to a mixture of CMIT/MIT from HD.

METHODS

Twenty-four children who were only exposed to a mixture of CMIT/MIT, with no previous underlying disease, were assessed by IOS. Diagnostic criteria for HDLI were categorized as definite, probable, possible, or unlikely. Home visits and administration of a standardized questionnaire were arranged to assess exposure characteristics.

RESULTS

Definite and probable cases showed higher airborne disinfectant exposure intensity during sleep (32.4 ± 8.7 μg/m3) and younger age at initial exposure (3.5 ± 3.3 months) compared with unlikely cases (17.3 ± 11.0 μg/m3, p = 0.026; 22.5 ± 26.2 months, p = 0.039, respectively). Reactance at 5 Hz was significantly more negative in those with high-density exposure during sleep (mean, -0.463 kPa/L/s vs. low density, -0.296, p = 0.001). The reactance area was also higher with high-density exposure during sleep (mean, 3.240 kPa/L vs. low density, 1.922, p = 0.039). The mean bronchodilator response with high-density exposure was within the normal range for reactance.

CONCLUSIONS

Significant peripheral airway dysfunction were found in children with high levels of inhalation exposure to a mixture of CMIT/MIT during sleep. Strict regulation of a mixture of CMIT/MIT exposure were associated with positive effects on lung function of children.

Guidelines for the presentation of contact allergy case reports

Case reports constitute a classic publication format that is being increasingly appreciated, for example because of its educational value. In the field of contact dermatitis research, case reports often serve as sentinel publications concerning new allergens, or new exposures to known allergens, or regarding other conditions leading to contact dermatitis. The CARE guideline published in 2013 addresses standardized and complete reporting of case reports in all fields of medicine. The present article takes up the CARE suggestions, and further specifies these in terms of application to case reports in the field of contact dermatitis. The objective of this structured guidance is to provide junior or inexperienced doctors and researchers with an annotated list, against which the fulfilment of essential or optional items of a complete, high-quality case report to be submitted to Contact Dermatitis or other journals can be checked.

Occurrence and concentrations of isothiazolinones in detergents and cosmetics in Switzerland

BACKGROUND

In recent years, the frequency of contact allergy to isothiazolinones has increased alarmingly in Europe, but only limited data are available on concentrations of isothiazolinones in consumer products.

OBJECTIVES

To examine the current frequency of isothiazolinones [methylisothiazolinone (MI), methylchloroisothiazolinone (MCI), benzisothiazolinone (BIT), and octylisothiazolinone (OIT)] in a wide array of detergents and cosmetics relevant for the Swiss population.

METHODS

By means of a market survey, the occurrence of isothiazolinones was investigated in 1948 consumer products. Of these, 88 products were analysed by liquid chromatography-high-resolution mass spectrometry after ultrasonic extraction.

RESULTS

Only 7.6% of all cosmetics contained isothiazolinones, but the prevalence in detergents was much higher (42.9%). The measured concentration ranges in detergents were 4.3–10, 3.5–279, 3.8–186 and 7.9 ppm (one product only) for MCI, MI, BIT, and OIT, respectively [corrected]. For cosmetics, these were 1.3-133 and 4.8 ppm (one product only) for MI and MCI, respectively.

CONCLUSIONS

Our study has shown that high concentrations of isothiazolinones (including MI) can be found in a large variety of products, in particular in detergents. Therefore, the safe use of these preservatives should be re-evaluated by including detergents in the exposure assessment.

The Spanish standard patch test series: 2016 update by the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC)

The Spanish standard patch test series, as recommended by the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC), has been updated for 2016. The new series replaces the 2012 version and contains the minimum set of allergens recommended for routine investigation of contact allergy in Spain from 2016 onwards. Four haptens -clioquinol, thimerosal, mercury, and primin- have been eliminated owing to a low frequency of relevant allergic reactions, while 3 new allergens -methylisothiazolinone, diazolidinyl urea, and imidazolidinyl urea- have been added. GEIDAC has also modified the recommended aqueous solution concentrations for the 2 classic, major haptens methylchloroisothiazolinone and methylisothiazolinone, which are now to be tested at 200ppm in aqueous solution, and formaldehyde, which is now to be tested in a 2% aqueous solution. Updating the Spanish standard series is one of the functions of GEIDAC, which is responsible for ensuring that the standard series is suited to the country's epidemiological profile and pattern of contact sensitization.

Positive lists of cosmetic ingredients: Analytical methodology for regulatory and safety controls - A review

Cosmetic products placed on the market and their ingredients, must be safe under reasonable conditions of use, in accordance to the current legislation. Therefore, regulated and allowed chemical substances must meet the regulatory criteria to be used as ingredients in cosmetics and personal care products, and adequate analytical methodology is needed to evaluate the degree of compliance. This article reviews the most recent methods (2005-2015) used for the extraction and the analytical determination of the ingredients included in the positive lists of the European Regulation of Cosmetic Products (EC 1223/2009): comprising colorants, preservatives and UV filters. It summarizes the analytical properties of the most relevant analytical methods along with the possibilities of fulfilment of the current regulatory issues. The cosmetic legislation is frequently being updated; consequently, the analytical methodology must be constantly revised and improved to meet safety requirements. The article highlights the most important advances in analytical methodology for cosmetics control, both in relation to the sample pretreatment and extraction and the different instrumental approaches developed to solve this challenge. Cosmetics are complex samples, and most of them require a sample pretreatment before analysis. In the last times, the research conducted covering this aspect, tended to the use of green extraction and microextraction techniques. Analytical methods were generally based on liquid chromatography with UV detection, and gas and liquid chromatographic techniques hyphenated with single or tandem mass spectrometry; but some interesting proposals based on electrophoresis have also been reported, together with some electroanalytical approaches. Regarding the number of ingredients considered for analytical control, single analyte methods have been proposed, although the most useful ones in the real life cosmetic analysis are the multianalyte approaches.

The fate of two isothiazolinone biocides, 5-chloro-2-methylisothiazol-3(2H)-one (CMI) and 2-methylisothiazol-3(2H)-one (MI), in liquid air fresheners and assessment of inhalation exposure

There exist public concerns regarding the two most widely used isothiazolinones (5-chloro-2-methylisothiazol-3(2H)-one (CMI) and 2-methylisothiazol-3(2H)-one (MI)) in various consumer products because they cause allergic responses in dermatitis and are potentially harmful when inhaled. Hydrolysis and photolysis tests for CMI and MI at pH 4, 7, and 9 were performed to evaluate their stability. While MI did not degrade under the test conditions, CMI slightly degraded at pH 9 via hydrolysis and at pH 4 via photolysis. To better understand human exposure to MI and CMI during the use of consumer products, the vaporization rates of MI and CMI from two commercial air fresheners were quantified in a custom-made chamber. The evaporation of MI was almost negligible over 7 d, whereas a significant amount of CMI evaporated over the same period. Because the volume of air freshener decreases over time due to evaporation of water, the MI concentration in the product increased by a factor of 1.8-2.2. The air concentration of CMI was predicted using a ConsExpo model using a fixed weight fraction (model 1) and a new model that reflects changes in the concentrations of active ingredients and the product volume over time (model 2). The concentration determined using model 1 reached a steady-state value of 0.032 µg L(-1), whereas that predicted using model 2 increased consistently. Inhalation exposure was also assessed using two exposure scenarios: a room and a car. Both calculated values of margin of exposure were much higher than 300, indicating a negligible inhalation risk.

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.

Methylisothiazolinone: dermal and respiratory immune responses in mice

Methylisothiazolinone (MI), a widely used chemical preservative in industrial and household products, and cosmetics, has been associated with allergic contact dermatitis. However, the asthmogenic capacity of MI is currently unknown. In this study, we investigated the capacity of MI to elicit asthma-like responses in a validated mouse model. On days 1 and 8, mice (C57Bl/6 and BALB/c) were dermally treated with MI or vehicle on each ear. On day 15, mice received a single intranasal challenge with MI or vehicle. Immediately after the challenge, the early ventilatory response was measured using a double chamber plethysmograph. One day later, airway hyperreactivity, pulmonary inflammation and immune-related parameters were assessed. Dermal treatment with MI in both C57Bl/6 and BALB/c mice induced increased T- and B-cell proliferation in the auricular lymph nodes, along with IFN-γ production and limited increases in total serum IgE, confirming dermal sensitization. An airway challenge with MI led to an early ventilatory response (decreased breathing frequency), indicative for acute sensory irritation. However, 24h later no allergic respiratory response (no airway hyperreactivity (AHR) nor pulmonary inflammation) was found in either mouse strains. Our study indicates that MI can be classified as a strong dermal sensitizer and irritant, but not an asthmogen after initial dermal sensitization, followed by an airway challenge.