Allergic contact dermatitis from Euxyl K 400

Should methyldibromo glutaronitrile continue to be used in the European baseline Series? A REIDAC national cross-sectional study

BACKGROUND

Methyldibromo glutaronitrile (MDBGN) was one of the most frequent and relevant allergens found in patch testing at the beginning of this century. In 2008, this preservative was banned from cosmetics in Europe and ever since the prevalence of contact allergy to MDBGN has progressively decreased. Despite that gradual decline, MDBGN is still patch-tested in most baseline series. This study assessed the frequency of MDBGN sensitization, epidemiological characteristics of allergic patients, and the relevance of positive patch tests in a nationwide Spanish registry (REIDAC).

PATIENTS AND METHODS

We evaluated consecutively patch-tested patients in all participating centres. Using these data, we calculated the proportion of patients with positive patch tests to MDBGN from June 2018 to June 2020 and evaluated the relevance of the positive patch tests.

RESULTS

One hundred and fourteen out of 5072 (2.24 %) tested patients were sensitized to MDBGN. Clinical current relevance was confirmed in only one case.

CONCLUSION

Although the frequency of contact allergy to MDBGN remains high, no clinical significance was found in most of these patients (5072 tests needed to obtain one relevant positive result). The clinical usefulness of this allergen seems weak and its continued inclusion in the European baseline series is questionable.

HIGHLIGHTS

In 2008 methyldibromo glutaronitrile (MDBGN) was banned from cosmetics in Europe and since then, the prevalence of allergy to it has progressively decreased. Nevertheless, it is still being tested in European baseline series. This study assessed the frequency of MDBGN sensitization, epidemiological characteristics of allergic patients as well as the relevance of positive patch tests in a nationwide registry (REIDAC). The frequency of allergy to MDBGN remains high, but no clinical significance was found. Most of these patients are aged >40 years and probably represent historical sensitizations.

Patch Testing to Methyldibromoglutaronitrile/Phenoxyethanol: North American Contact Dermatitis Group Experience, 1994-2018

BACKGROUND

Methyldibromoglutaronitrile/phenoxyethanol (MDBGN/PE) is a broad-spectrum preservative mixture used in consumer and industrial products.

OBJECTIVES

The aims of the study were (1) to characterize the prevalence and clinical relevance of patch test reactions to MDBGN/PE and the epidemiology of positive patients and (2) to determine the frequency of concomitant reactions of MDBGN/PE and its components.

METHODS

This study used a retrospective analysis of cross-sectional data compiled by the North American Contact Dermatitis Group from 1994 to 2018.

RESULTS

Of 55,477 tested patients, 2674 (4.8%) had positive patch test reactions to MDBGN/PE (1.0%-2.5% petrolatum [pet]); most were + (63.3%) or ++ (22.3%). Clinical relevance was considered definite in 3.0% and probable in 19.3% of reactions. Common dermatitis sites included the hands (26.4%), scattered/generalized distribution (24.7%), and the face (18.3%). Patients with a positive reaction to MDBGN/PE and/or MDBGN and/or PE were significantly more likely to be male and older than 40 years and/or had hand dermatitis (P ≤ 0.0033). Positivity to MDBGN/PE 2.0% pet decreased significantly over time (from 6.0% in 1998-2000 to 2.5% in 2017-2018, P < 0.0001). Personal care products were the most common exposure source (53.2%).

CONCLUSIONS

Over time, positivity to MDBGN/PE 2.0% pet decreased significantly from 6.0% (in 1998-2000) to 2.5% (in 2017-2018). The high proportion of weak (63.3%) reactions underscore the need for careful interpretation of patch test sites. Important demographic associations included male sex and age older than 40 years.

Final Report on the Safety Assessment of Methyldibromo Glutaronitrile

The halogen compound Methyldibromo Glutaronitrile is used in a wide variety of cosmetics as a preservative. Concentrations in cosmetic formulations reportedly range from 0.0075 to 0.06%. The oral LD50 in rats is 640 mg/kg. Dogs on a diet of 4,000 ppm Methyldibromo Glutaronitrile for 13 weeks developed thyroid hyperplasia; those on a diet of 167 ppm exhibited no hyperplasia, although the thyroid glands were enlarged. Application of Methyldibromo Glutaronitrile at a level of 4.0 g/kg to the skin of rats for 21 days produced severe irritation. A concentration of 0.025% applied to the skin of rabbits in a 28-day dermal toxicity study resulted in only slight to moderate irritation. No evidence of sensitization was found in guinea pig studies, nor was photosensitization reported in mouse studies. No reproductive or developmental toxicity was noted in two rat studies. Methyldibromo Glutaronitrile was not mutagenic in a series of mammalian system tests. Clinical data using repeat insult patch testing (HRIPT) methods indicated that concentrations as low as 0.025% produced a positive reaction in a few individuals. To limit the possibility that formulations containing this ingredient will lead to sensitization, it was concluded that leave-on formulations should contain 0.025% Methyldibromo Glutaronitrile. Rinse-off formulations, because the duration of exposure is much less, are considered safe as currently used

Contact allergy epidemics and their controls

Contact dermatitis can be severe and lead to sick leave as well as significant healthcare expenses. The aim of this review is to present the published knowledge on 6 historical epidemics of contact allergy to apply this knowledge on the prevention and control of future contact allergy epidemics. A historical review is performed on nickel, chromium, methyl-chloro-iso-thiazolinone/methyl-iso-thiazolinone, methyl-di-bromo glucaro-nitrile, formaldehyde, and para-phenylenediamine. The first cases of contact dermatitis are mostly occupational, whereas consumer cases appear later. There is often a latency period from the first cases are observed until an epidemic occurs, and the problem is recognized. Finally, no one seems to take responsibility of dealing with the situation, and there are no attempts of regulation until an epidemic is consolidated among consumers for many years. Steps should be taken to prevent contact allergy epidemics. It is essential that dermatologist, scientists, administrators, and consumers organize and structure known methods to accelerate the control of emerging contact allergens.

Allergic Contact Dermatitis to Cosmetics

Cosmetics are used to enhance one's appearance and are used by women worldwide. This article reviews the epidemiology, clinical features, and management of cosmetic allergic contact dermatitis. Additionally, several important cosmetic-related allergens are discussed.

Hypersensitivity to preservatives

Preservatives are biocidal chemicals added to cosmetics, topical medicaments, consumer goods, foods, and industrial products to protect them against microbial spoilage and to protect the consumer against infection. The ideal preservative, both effective and devoid of irritant or sensitizing potential, is still to be discovered. The present paper reviews the most important classes of preservatives, namely parabens, formaldehyde-releasers, and isothiazolinones. The author also discusses newer agents such as Euxyl K 400 and isopropynyl butylcarbamate. Each preservative is described in terms of chemical and physical characteristics, antimicrobial efficacy, exposure, cutaneous adverse reactions, patch testing concentrations, patterns of cross-reactions, and reported rates of sensitization. The history of preservatives goes back to the 1930s, and ironically, the parabens, which the industry has sought to replace with "safer" alternatives, are still the most frequently used biocides in cosmetics and appear to be far less sensitizing than most of the newer agents.

The British standard series of contact dermatitis allergens: validation in clinical practice and value for clinical governance

BACKGROUND

All centres use an empirically determined set of 'standard' test allergens for patch testing that contain the commoner environmental sensitizers. Objectives To assess the validity of the British standard series of 12 allergens used in addition to the 23 already in the European standard series.

PATIENTS AND METHODS

Results for 3062 consecutive patients patch tested in seven centres across the United Kingdom during the year 2000 were analysed.

RESULTS

The additional allergens from the British series and positive rates were: methyl dibromoglutaronitrile 2.4%, carba mix 1.6%, tixocortol pivalate 1.5%, ethylenediamine 1.3%, cetearyl alcohol 0.8%, 2-bromo-2-nitropane-1,3-diol 0.8%, diazolidinyl urea 0.7%, chlorocresol 0.6%, budesonide 0.6%, fusidic acid 0.5%, imidazolidinyl urea 0.5%, and chloroxylenol 0.4%. The allergens with the lowest positive rate in the European standard series were primin at 0.6% and isopropyl-phenyl-para-phenylenediamine at 0.4%.

CONCLUSIONS

The 12 allergens in the British series should continue being tested as a standard addition to the European series within the U.K. The collection of data in this manner to allow comparisons between centres shows differences that reflect selection criteria and interpretation of results, and offers a useful tool for audit and clinical governance. Testing fewer than 1 : 2150 population may indicate underprovision of service. Similarly, rates of sensitization for nickel contact allergy above 26% and for fragrance mix above 16% (the upper 95% confidence intervals) should stimulate inquiry into the reasons behind this.

Methyldibromoglutaronitrile (Euxyl K 400): an important "new" allergen in cosmetics

Euxyl K 400 is a preservative system for cosmetics and toiletries that contains phenoxyethanol and methyldibromoglutaronitrile in a 4:1 ratio. In The Netherlands, Italy, and Germany, the prevalence of allergy to Euxyl K 400 has risen in the past 4 years and is currently 2% to 4% in patients suspected of having contact dermatitis. The allergenic ingredient is nearly always methyldibromoglutaronitrile. Causative products include both stay-on and rinse-off cosmetics and moistened toilet tissue. Because the causative products usually give false-negative reactions, the allergen, methyldibromoglutaronitrile, should be tested in all patients suspected of having cosmetic dermatitis and in those with perianal dermatitis. We suggest a test concentration of 0.3% to 0.5% in petrolatum.

Methyldibromoglutaronitrile is an important contact allergen in The Netherlands

From 15 May to 15 December 1994, 2943 patients suspected of having contact dermatitis (1955 women, 988 men) were patch tested with methyldibromoglutaronitrile 0.3%, 0.1% and 0.05% pet. 119 patients (4.0%; women 4.1%, men 3.8%) proved to be allergic. 71% of the reactions were considered to be relevant. In 2/3 of the patients, causative products were cosmetics, in 1/3 moistened toilet tissues. Testing with methyldibromoglutaronitrile at lower concentrations (0.05% and 0.1%) and with commercial allergens (Euxyl K 400 and methyldibromoglutaronitrile, both containing methyldibromoglutaronitrile 0.1%), resulted in a number of false-negative reactions. All preservatives in the European standard series had lower scores than the 4% positive reactions to methyldibromoglutaronitrile (formaldehyde 2.0%, MCI/MI (Kathon CG) 3.2%, parabens 1.0%, quaternium-15 1.3%). It is concluded that methyldibromoglutaronitrile (present in the commercial preservative Euxyl K 400) is an important contact allergen in the Netherlands in cosmetics and moistened toilet tissues. It should be added to cosmetics series and to proctological series. The optimal test concentration is unknow, but may be 0.3% pet. The concentration of 0.1% methyldibromoglutaronitrile in the currently available commercial allergens appears to be too low, resulting in a number of false-negative reactions.

Euxyl K 400: incidence of sensitization, patch test concentration and vehicle

The aim of this study was to verify the most suitable vehicle and concentration for testing Euxyl K 400 and its individual ingredients, and to evaluate the prevalence of sensitization to this preservative over the years in Italy. From January 1991 to October 1994, Euxyl K 2.5% pet. was positive in 99 patients (35 male, 64 female) out of 3455 (2.8%). Of these, 22 out of 855 patients had a positive reaction during 1991 (2.6%), 29 out of 1037 in 1992 (2.8%), 28 out of 858 in 1993 (3.3%), and 20 out of 705 in 1994 (2.8%). 51 of the 99 patients with a reaction to Euxyl K 400 2.5% pet. showed a positive reaction to dibromodicyanobutane 0.5% pet. and 2 to phenoxyethanol 5% pet. The results of patch testing with serial dilutions of Euxyl K 400 in different vehicles indicate that water is a good vehicle for testing the preservative. However, since Euxyl K 400 is only hydrosoluble to a limited extent, the maximum concentration that can be tested using water is 0.5%, and so with this concentration about 40% of sensitized patients are missed. The results of patch testing with serial dilutions of Euxyl K 400 in petrolatum demonstrate that concentrations lower than 2.5% are not suitable for detection of all sensitized patients. Euxyl K 400 in ethanol frequently causes irritant reactions without offering significant advantages in detecting sensitized patients.

The sensitizing potency of Euxyl K 400 and its components 1,2-dibromo-2,4-dicyanobutane and 2-phenoxyethanol

Using a modified FCA (Freund's complete adjuvant) procedure, the sensitizing capacity of Euxyl K 400 and its ingredients, 1,2-dibromo-2,4-dicyanobutane and 2-phenoxyethanol, has been studied in guinea pigs. The experiments demonstrate that a distinct but weak sensitizing potency exists for Euxyl K 400 and dibromodicyanobutane. Phenoxyethanol remained almost negative. These results are in good accordance with the low number of cases of allergic contact dermatitis due to Euxyl K 400 and dibromodicyanobutane described since their introduction on the market. Cases of phenoxyethanol contact allergy have been published hitherto only 4x in the medical literature.

Determination of methyldibromoglutaronitrile in cosmetic products by high performance liquid chromatography with electrochemical detection

Synopsis A method for the determination of methyldibromoglutaronitrile in cosmetic products is described. Reversed phase high performance liquid chromatography and reductive electrochemical detection is employed to provide for improved selectivity and detectability compared to alternative methods. The method detects 0.002% methyldibromoglutaronitrile in cosmetic products and has a linear range from 0.006 up to 0.06%, which can easily be extended to the legally allowed limit of 0.1% by means of a simple dilution step. At a level of 0.03% the coefficient of variation was estimated to be 1.7%. Recoveries measured were between 98 and 100%. The method has been subjected to a ruggedness test, which indicated that it was stable, but slightly sensitive for a decrease in the detection potential. More than 130 cosmetic products have been analysed using the method. In 19 samples methyldibromoglutaronitrile was detected in concentrations varying between 0.002% and 0.030%. Résumé Une méthode a été mise au point pour la détermination du methyldibromoglutaronitrile, un conservateur cosmétique dont l'utilisation est croissante. La méthode utilise la chromatographie liquide à haute performance avec détection électrochimique pour permettre une amélioration de la détection et de la spécificité. Selon une procédure simple, le methyldibromoglutaronitrile est séparé sur une colonne 100 RP8 (lichosphere MERCK) avec une phase mobile constituee d'eau et d'acétone (60/40 v/v) avec un ajout de sulfate de sodium et du chlorure de sodium pour obtenir des concentrations de 0.02 M et 0.002 M respectivement. Une électrode en or a été utilisée pour la détection avec un potentiel de fonctionnement de -0.6 V réductif. Une détection par pulsation a été nécessaire pour obtenir une réponse stable. Le détecteur a été programmé pourgarder l'électrode pour 10 ms à 1 V, 10 ms à-1 V (réductif) et à-0.6 V pour 100 ms, ce potentiel a été utilisé comme mesure. Des courbes de calibration linéaire ont été obtenues sur une gamme de 0.006%à 0.06% methyldibromoglutaronitrile. Une concentration de 0.002% de methyldibromoglutaronitrile a pu être détectée par un rapport signal/bruit supérieur à 2,5. La reconstitution d'un échantillon, doséà 0.03% de methyldibromoglutaronitrile a atteint 98% d'après les mesures sur la surface des pics et 100% en calculant la hauteur des pics. La déviation relative calculée sur des éxpériences d'extraction indépendantes à partir du même échantillon dosé a été estimée à 1.7%. La méthode a été soumise à un test de robustesse. Les divers paramétres étaient les suivants: la quantité d'échantillons soumis à l'analyse; le temps d'extraction et le temps durant lequel la solution extraite a été mélangée; la composition du solvant d'extraction; la température de la colonne; le temps de pulsation du détecteur et le potentiel de fonctionnement.

Euxyl K 400: a new sensitizer in cosmetics

Euxyl K 400 is a preservative for cosmetics and toiletries containing 2 active ingredients, 1,2-dibromo-2,4-dicyanobutan and 2-phenoxyethanol. 2057 consecutive patients with contact dermatitis were patch tested with Euxyl K 400 2.5% pet. and ethanol. A positive patch test occurred in 24 patients (1.2%). The source of sensitization was traced in 8 patients to their cosmetics. Both leave-on and rinse-off products were responsible. Further patch tests with Euxyl K 400 0.5% pet. and phenoxyethanol 5% pet. were performed in 11 patients. A positive patch test to phenoxyethanol was detected in 1 of them. Only 3 patients showed a mild reaction to Euxyl K 400 0.5%. A provocative use test with a lotion preserved with Euxyl K 400 0.1% was positive in 5 of these 11 patients. Patients with Euxyl K 400 sensitivity showed a high prevalence of positive patch tests to other common ingredients of cosmetics. Since the use of Euxyl K 400 in cosmetic products is rapidly increasing, it should be included in the patch test series for patients with suspected cosmetic allergy.