Methyldibromoglutaronitrile in rinse-off products causes allergic contact dermatitis: an experimental study

High prevalence but no current clinical relevance of methyldibromo glutaronitrile since its ban in Turkey in 2015

BACKGROUND

Regulatory actions significantly reduced methyldibromo glutaronitrile (MDBGN)-induced allergic contact dermatitis (ACD) from cosmetics in Europe. Turkey banned MDBGN in 2015.

OBJECTIVES

To assess sensitization and ACD rates to MDBGN before and after its ban in Turkey.

METHODS

Data from 2653 consecutively patch tested patients between 1996 and 2023 with MDBGN 0.1% pet. (n = 573) or 0.2%-0.3% pet. (n = 1310) or 0.5% pet. (n = 770) were analysed. MDBGN was tested as MDBGN/phenoxyethanol (PE) in 1434 patients.

RESULTS

The sensitization prevalence was 1.7% (45/2653), peaking at 5.3% in 2018 and 2023 with MDBGN 0.3% pet. There was a two-fold male predominance, with patients exclusively ≥20 years old. None of the patients reacted to PE. ACD occurred in 0.7% (19/2653), mainly affecting hands and linked to non-occupational exposure (78.9%), particularly from rinse-off/leave-on cosmetics. The pattern of 'middle-aged men with hand eczema and fragrance allergy' was particularly notable. Occupational ACD was rare (21.1%), occurring mainly in hairdressers from hair gel. Positive reactions with current clinical relevance dropped from 48.3% (1996-2014) to zero after 2015 (p < 0.001).

CONCLUSIONS

The ban effectively reduced MDBGN-induced ACD in Turkey, yet the prevalence of positive patch test reactions remains high, likely due to past exposures or other undisclosed sources. We suggest continued testing of MDBGN in the EBS in Turkey.

Contact allergy induced by bisphenol A diglycidyl ether leachables from aluminium tubes for pharmaceutical use

BACKGROUND

Aluminium tubes for pharmaceutical use are internally lacquered with epoxy resins (ER) based on bisphenol A diglycidyl ether (BADGE). Recently, it was shown that remnants of ER polymerization like BADGE are extractable from epoxy-based coatings of commercially available tubes and may leach into semi-solid drug preparations. We aimed to evaluate the safety of BADGE-contaminated macrogol ointments in individuals sensitized to ER based on BADGE by use tests.

METHODS

Repeated open application testing (ROAT) in 11 patients sensitized to ER based on BADGE with BADGE in macrogol ointments (3 mg/kg; 30 mg/kg, equivalent to BADGE concentration determined in macrogol ointment after storage in a commercially available tube; 300 mg/kg).

RESULTS

The 30 mg/kg BADGE ointment elicited reactions in three patients, and another three patients reacted to 300 mg/kg BADGE ointment. No reactions to the vehicle control and 3 mg/kg BADGE were observed.

CONCLUSIONS

Elevated BADGE concentrations in ER-coated aluminium tubes pose a risk of developing contact dermatitis to patients sensitized to ER based on BADGE. Quality standards are deemed necessary for the production of ER-coated aluminium tubes intended for pharmaceutical use and should consider the results of the present ROAT study.

Allergic contact dermatitis in children: which factors are relevant? (review of the literature)

Allergic contact dermatitis (ACD) in children is increasing. Sensitization to contact allergens can start in early infancy. The epidermal barrier is crucial for the development of sensitization and elicitation of ACD. Factors that may influence the onset of sensitization in children are atopic dermatitis, skin barrier defects and intense or repetitive contact with allergens. Topical treatment of ACD is associated with cutaneous sensitization, although the prevalence is not high. ACD because of haptens in shoes or shin guards should be considered in cases of persistent foot eruptions or sharply defined dermatitis on the lower legs. Clinical polymorphism of contact dermatitis to clothing may cause difficulties in diagnosing textile dermatitis. Toys are another potentially source of hapten exposure in children, especially from toy-cosmetic products such as perfumes, lipstick and eye shadow. The most frequent contact allergens in children are metals, fragrances, preservatives, neomycin, rubber chemicals and more recently also colourings. It is very important to remember that ACD in young children is not rare, and should always be considered when children with recalcitrant eczema are encountered. Children should be patch-tested with a selection of allergens having the highest proportion of positive, relevant patch test reactions. The allergen exposure pattern differs between age groups and adolescents may also be exposed to occupational allergens. The purpose of this review is to alert the paediatrician and dermatologist of the frequency of ACD in young children and of the importance of performing patch tests in every case of chronic recurrent or therapy-resistant eczema in children.

The dose-response relationship between the patch test and ROAT and the potential use for regulatory purposes

BACKGROUND

Allergic contact dermatitis is common and can be prevented. The relationship between thresholds for patch tests and the repeated open application test (ROAT) is unclear. It would be desirable if patch test and ROAT data from already sensitized individuals could be used in prevention.

OBJECTIVES

The aim was to develop an equation that could predict the response to an allergen in a ROAT based on the dose-response curve derived by patch testing.

MATERIALS/METHODS

Results from two human experimental elicitation studies with non-volatile allergens, nickel and the preservative methyldibromo glutaronitrile (MDBGN), were analysed by logistic dose-response statistics. The relation for volatile compounds was investigated using the results from experiments with the fragrance chemicals hydroxyisohexyl 3-cyclohexene carboxaldehyde and isoeugenol.

RESULTS

For non-volatile compounds, the outcome of a ROAT can be estimated from the patch test by: ED(xx)(ROAT) = 0.0296 ED(xx)(patch test). For volatile compounds, the equation predicts that the response in the ROAT is more severe than the patch test response, but it overestimates the response.

CONCLUSIONS

This equation may be used for non-volatile compounds other than nickel and MDBGN, after further validation. The relationship between the patch test and the ROAT can be used for prevention, to set safe levels of allergen exposure based on patch test data.

Hand dermatitis: a focus on allergic contact dermatitis to biocides

Hand dermatitis is a common disease of the skin resulting in significantly decreased quality of life. Allergic contact dermatitis is a frequent cause of hand dermatitis. Recent studies have revealed that biocides used as preservatives are frequent allergens affecting the hands. This article reviews common biocides implicated in hand dermatitis.

New aspects in allergic contact dermatitis

PURPOSE OF REVIEW

To give selected new information on contact allergy and allergic contact dermatitis with focus on diagnostic procedures and pitfalls.

RECENT FINDINGS

Recent studies dealing with common contact allergens have improved our understanding of the relationship between positive patch tests and the clinical interpretation and consequences for the patient.

SUMMARY

Nickel allergy is still the most common contact allergy in Europe in spite of full implementation of the EU Nickel Directive in 2001. Contact allergens in cosmetics and topical drugs are another common cause of allergic contact dermatitis. The main culprits include fragrance chemicals, preservatives, and hair dyes. We are all more or less exposed to cosmetics and topical drugs on a daily basis. The labelling requirements given in the Cosmetics Directive is of great help in tracing the causative allergenic ingredients. Most of the components present in cosmetic products are also occurring in household and industrial products, often under other trade names. Patients with multiple contact allergies constitute a special problem because their quality of life is severely affected by the multitude of eliciting products in the environment. We still lack a good understanding of why these patients become so easily sensitized.

Occupational allergic contact dermatitis to methyldibromoglutaronitrile in hand degreasing toilet paper

We inform about a case of occupational allergic contact dermatitis (OACD) to methyldibromoglutaronitrile (MDBGN) in industrial hand degreasing moist toilet paper. To our knowledge, this is the first published case of OACD to MDBGN in industrial hand degreasing toilet papers. A cause-effect relationship seems to be clearly established. We believe that physicians must keep in mind that MDBGN is a strong allergen either mixed or as a single component of industrial moist toilet papers. MDBGN must be taken into account for OACD at an appropriate work environment.

Intermittent exposure to low-concentration paraphenylenediamine can be equivalent to single, higher-dose exposure

Hair dye allergy is an important and increasingly common cause of allergic contact dermatitis. The role of repeated exposure in elicitation of allergy has not previously been extensively studied. We have therefore compared elicitation between single and intermittent exposure to paraphenylenediamine (PPD). 23 subjects known to be allergic to PPD from positive patch tests were exposed to 0.3% and 0.03% PPD, both in petrolatum and water, for 5 min at the same site every day for up to 8 D. In the same subjects, single exposures were also performed at different sites, from 5 to 40 min. Other experiments exposed rat skin to radiolabelled PPD as one-off application or multiple exposures. There were 8 reactions in the cumulative exposure site using 0.3% PPD in aqueous solution. In 7 of these, there was an exact correlation with reaction to the cumulative time needed for repeat exposures to elicit a reaction and the time needed for a reaction to the single exposure. There were no reactions to 0.03% PPD in water or pet under either type of exposure condition. There was also a positive correlation between grade of original reaction in clinic (+++, ++, +) and appearance/intensity of elicitation reactions. In the animal study, cumulative time and single exposure time sites correlated with regards to retention of radiolabelled substance within the skin. This study therefore demonstrates for the first time that, over the time period tested, the allergenic component of PPD accumulates in the skin. Hence, intermittent exposure to lower concentrations of PPD may be equivalent to higher concentration, one-off exposure.

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.

Benzophenone 4: an emerging allergen in cosmetics and toiletries?

Chemical ultraviolet (UV) filters have, over the last few decades, been increasingly used not only in conventional sunscreen products but also in many cosmetics and toiletries. Allergic contact dermatitis as well as photoallergic contact dermatitis reactions have been well documented as a consequence of such use. Over a 3-year period, we recorded the number of positive patch test reactions to a selection of chemical UV filters that we added to our usual cosmetics/facial series. Our objective was to investigate whether any of these filters produced significant numbers of positive patch test results in the absence of photostimulation. Our results show that not only did benzophenone 4 (2-hydroxy-4-methoxybenzophenone-5-sulphonic acid: sulisobenzone) produce significantly more positive patch test results than the other UV filters that were tested, but also it was the third most frequently positive result overall. Our findings would support the inclusion of benzophenone 4 when patch testing to investigate likely contact dermatitis from cosmetics and toiletries.

Patch test results in patients with scalp dermatitis: analysis of data of the Information Network of Departments of Dermatology

BACKGROUND

Contact dermatitis of the scalp may develop primarily due to exposure to cosmetic products or secondarily due to application of topical medicaments on affected skin.

OBJECTIVES

To illustrate the current spectrum of allergens in scalp dermatitis.

PATIENTS/METHODS

Data of 1320 patients recorded by the Information Network of Departments of Dermatology (IVDK) between 1993 and 2003, who were patch tested to confirm or rule out (secondary) allergic contact dermatitis of the scalp, were analysed.

RESULTS

Sensitization to p-phenylenediamine, tolune-2,5-diamine, p-aminophenol, 3-aminophenol, p-aminoazobenzene, cocamidopropyl betaine and pyrogallol was significantly more common than in the remaining IVDK patients. In 690 patients, altogether 4070 patients' own products were patch tested. Medical products, hair tints and bleaches (HTB) and hair-cleansing products together caused nearly 2/3 of positive patch test reactions. Among these categories, HTB showed the highest percentage of positive patch test reactions; 24 of 29 HTB-positive patients had no positive reaction to any of the commercially available allergens.

CONCLUSIONS

In our subgroup of patients with scalp dermatitis, constituents of hair-colouring products were the most important allergens. As some ingredients of hair dyes are not contained in patch test series, testing of patients' own products is an important part of diagnostic workup, as otherwise sensitizations may be missed.

Information derived from sensitization test methods: test sensitivity, false positives and false negatives

Predictive toxicology tests for the prospective identification of skin-sensitizing chemicals are well known and have been used for many years. However, of these, only the local lymph node assay (LLNA) has actually undergone formal independent assessment to determine the accuracy of the predictions, particularly with respect to the likelihood of false positives and false negatives. Often, efforts to increase the sensitivity of a test (reducing false negatives) tend to increase the number of false positives. In this short review, these issues are discussed in particular relation to the 3 predictive tests available in regulatory toxicology, the guinea-pig maximization test, the occluded patch test of Buehler and the LLNA. A key perspective is that no predictive test is without limitations; having a good appreciation of these limitations is necessary for making the best use of the information derived from these methods.

Identification and classification of skin sensitizers: identifying false positives and false negatives

The first step in regulatory evaluation of substances involves the identification of their intrinsic hazards, including the potential for skin sensitization. This is, quite properly, entirely different from assessment of the risks to human health, which might arise from incorporation of substances in products. EU guidance on regulations concerning the classification of skin sensitizers suggests a range of sources of information be deployed in the hazard identification process. These include chemical structure, predictive animal tests, and various types of human data. Where the information is clear-cut, then uncertainties rarely arise. However, for some materials, discordant information arises, perhaps because the substance is on the borderline of test sensitivity and classification (sensitizing materials of insufficient potency do not classified according to the EU scheme), due to conflicting results in predictive tests or for other reasons. In this study, we review data on a number of substances where a classification decision is complicated by such discordances and seek to use these examples to demonstrate how best to make a weight of evidence decision on whether a substance should, or should not, be classified as a skin sensitizer.

A clinically relevant contact allergy to methyldibromo glutaronitrile at 1% (0.32 mg/cm2) detected by a patch test

Recently, the preservative methyldibromo glutaronitrile (MDBGN) at 0.5% w/w in petrolatum was included in the European standard patch test series based on the studies on chemical stability and consideration of rates of contact allergy, doubtful and irritant reactions as well as information on clinical relevance represented by results of a repeated open application test (ROAT) and patch test concentrations required to diagnose allergic contact dermatitis from MDBGN in individual cases. In this report, a case with a clinically relevant contact allergy to MDBGN, which on the mandatory reading occasion on D3 only was traced by a patch test with MDBGN at 1.0% (0.32 mg/cm2), is presented. The patient suffered from a chronic hand dermatitis, and when the patient stopped using a liquid soap containing MDBGN, the hand dermatitis substantially improved. A ROAT performed in a blinded and controlled way with applications twice daily on the hands with 2 moisturizers with and without MDBGN resulted in a deterioration of the hand dermatitis on the hand to which the MDBGN-preserved moisturizer had been applied.

Clinical update on contact allergy

PURPOSE OF REVIEW

The aim of this article is to review recent findings in contact allergy, regarding clinical research.

RECENT FINDINGS

The biocide methyldibromo glutaronitrile was identified to be an important sensitizer. Subsequently, it was banned from leave-on cosmetics in the European Union. Another group of important allergens that have been studied extensively included the fragrances oak moss absolute, isoeugenol, hydroxyisohexyl 3-cyclohexene carboxaldehyde and farnesol. A new fragrance mix II has been developed for standard testing, which includes the two latter compounds. Dose response studies have demonstrated broad individual variation of elicitation thresholds, dependent on the allergen concentration during induction, and other factors. Some unsuspected routes of exposure to allergens include oral, inhalational, connubial or airborne contact. Experimental studies provide a classification of newly introduced chemicals; increasingly, the local lymph node assay is supplementing and potentially replacing the guinea pig maximization test. Recent advances in occupational contact allergy include, for example, some attempts to improve diagnostics for epoxy resin and other plastic, glue, and cutting fluid components.

SUMMARY

Constant awareness for new allergens, confirmed by critical evaluation, standardization of patch test materials, and the identification of temporal patterns and subgroups at risk will improve both the diagnosis and prevention of allergic contact dermatitis.

Patch testing with patients' own cosmetics and toiletries - results of the IVDK*, 1998-2002

Patch test results with products brought in by the patients collected by the members of the Information Network of Departments of Dermatology (IVDK) between 1998 and 2002 were analysed. 5911 patients were patch tested with their own cosmetics and toiletries during this period. The 34 082 single test preparations applied to these 5911 patients were manually assigned to 1 of 26 categories, based on the EU Classification Annex I to 76/768/EEC, which had been further refined. The leave-on product category most commonly tested was 'creams, emulsions, lotions, gels and oils for the skin' (n = 3621 tested, n = 312 positive). The rinse-off product type most commonly tested was 'bath and shower preparations' (n = 1333 tested, n = 71 positive). In one-third of patients tested positive to these products, no other positive test result was observed. In the remainder, positive reactions to the fragrance mix, Myroxylon pereirae resin, methyldibromo glutaronitrile, (chloro-)methylisothiazolinone, 2-bromo-2-nitropropane-1,3-diole and further ingredients of cosmetics and toiletries were more common than in product-negative patients. However, in view of the potential for false-positive reactions mainly to rinse-off products, the results must be interpreted with caution. In conclusion, testing of patients' own products can be regarded as efficient and safe, if in accordance with current recommendations.

Quantitative patch and repeated open application testing in methyldibromo glutaronitrile-sensitive patients

Contact allergy to methyldibromo glutaronitrile (MDBGN), often combined with phenoxyethanol (PE) (e.g., Euxyl K 400), increased throughout the 1990s in Europe. Consequently, in 2003, the European Commission banned its use in leave-on products, where its use concentration was considered too high and the non-sensitizing use concentration as yet unknown. The 2 objectives of the study are (a) to find a maximum non-eliciting concentration in a leave-on product in MDBGN/PE-sensitized patients, which could possibly also be considered safe regarding induction and (b) to find the best patch test concentration for MDBGN. We, therefore, performed a use-related test (ROAT) in patients sensitized to MDBGN/PE (n = 39) with 3 concentrations of MDBGN/PE (50, 100 and 250 p.p.m. MDBGN, respectively). A subset of these patients (n = 24) was later patch-tested with various concentrations (0.1, 0.2, 0.3 and 0.5% MDBGN, respectively). 15 patients (38%, 95% confidence interval (CI) = 23-55%) had a negative and 24 (62%; 95% CI = 45-77%) a positive overall repeated open application test (ROAT) result. 13 reacted to the lowest (50 p.p.m.), 8 to the middle (100 p.p.m.) and 3 to the highest concentration (250 p.p.m.) only. In those 13 reacting to the lowest ROAT concentration, dermatitis developed within a few days (1-7). The strength of the initial and the confirmatory patch test result, respectively, and the outcome of the ROAT were positively associated. Of the 24 patients with a use and confirmatory patch test, 15 reacted to 0.1% MDBGN, 16 to 0.2%, 17 to 0.3% and 22 to 0.5%. With the patch test concentration of 0.5%, the number of ROAT-negative patients but patch-test-positive patients increases considerably, particularly due to + reactions. A maximum sensitivity of 94% (95% CI = 70-100%) is reached with a patch test concentration of 0.2%, and is not further improved by increasing the concentration. However, the specificity decreases dramatically from 88 (95% CI = 47-100%) with 0.2% to a mere 12.5% (95% CI = 0-53%) with 0.5%. It can be concluded (a) that for MDBGN 0.2% is very likely the best patch test concentration and (b) that 50 p.p.m. in a leave-on product can elicit contact dermatitis in sensitized persons. We were, therefore, unable to find a safe, still microbicidal, concentration for leave-on products. By contrast, with other contact allergens, dose-response use tests may be able to identify a non-eliciting concentration, which could give valuable clues to a non-inducing (i.e., safe) concentration in products.

Contact allergy to methyldibromo glutaronitrile - data from a 'front line' network

The preservative methyldibromo glutaronitrile (MDBGN) has caused an epidemic of contact allergy in Europe. However, most data concerning contact allergy comes from hospital departments of dermatology. As a part of the primary health care sector, Danish dermatologists in private practice provide the front line of care for patients with skin diseases. Data from this source may therefore better reflect trends in the general population than material from hospital departments of dermatology. In this study, the frequency of MDBGN allergy and the characteristics of patients seen by dermatologists in private practice were studied. In 1 year, 2146 patients were patch tested by the participating dermatologists from 4 clinics in various parts of Denmark. 5% (110) had positive patch tests to MDBGN, with no difference between the sexes. After adjustment was made for other background variables, multivariate analysis using logistic regression showed a significant association between hand eczema and MDBGN allergy (OR 2.5, P < 0.001). In 53 cases (52.4%), the patch test reaction to MDBGN was judged to be of current relevance. Creams and lotions accounted for 31% of the identified causative products and liquid soaps for 23%. It is concluded that contact allergy to MDBGN is frequent among patients seen by dermatologists in private practice. This is consistent with results from hospital departments of dermatology in Europe and indicates a general trend and ongoing epidemic in the general population. The significant relationship between hand eczema and MDBGN allergy is of concern, and the finding that wash-off products, especially liquid soaps, play a significant role in MDBGN allergy calls for a revision of the safety assessment of MDBGN in wash-off products.

Allergic contact dermatitis from methyldibromo glutaronitrile - clinical cases from 2003

Of the 766 patients with eczematous skin disease patch tested in 2003 at the Department of Dermatology, University Clinic Gentofte, 38 (4.9%) showed a positive reaction to methyldibromo glutaronitrile (MDBGN), and in an additional 2 patients, a doubtful positive patch test reaction was found to be of relevance. Among these, 27 had hand eczema, with a relevant exposure predominantly from wash-off products, either liquid soaps or shampoos, in 24 patients. Following identification of the allergen by patch testing and subsequent avoidance of products containing MDBGN, the hand eczema either improved or cleared in 19 patients. Chemical analysis showed 11 p.p.m. to 473 p.p.m. MDBGN in products used by the patients. Based on the present clinical study and accumulated evidence in the literature, it is concluded that MDBGN is not suitable for use in any type of cosmetic product.

Repeated open application test with methyldibromo glutaronitrile, a multicentre study within the EECDRG

Contact allergy to and allergic contact dermatitis from methyldibromo glutaronitrile (MDBGN) have frequently been reported. This study was initiated to help determine the optimal patch test preparation for MDBGN. In 51 patients with a doubtful or a positive patch test reaction to at least 1 of 4 test preparations with MDBGN in petrolatum at 1.0% w/w, 0.5%, 0.3% and 0.1%, a repeated open application test (ROAT) with moisturizers with and without MDBGN at 0.03% w/w was performed on the upper arms for 2 weeks. 18 of the 51 (35.3%) patients developed a positive ROAT. In all patients, there was a positive ROAT only to the moisturizer with MDBGN (P < 0.001). A statistically significant association was also found between the patch test reactivity (PTRL) and the outcome of the ROAT (P < 0.001). If only considering those with a PTRL above 0.3%, thus with negative or doubtful test reactions to 0.1% and 0.3%, there were still statistically significantly more patients with a positive ROAT to the moisturizer with MDBGN than to the moisturizer without MDBGN. The study demonstrates that patch testing with MDBGN at 0.3% and 0.1% will miss clinically relevant patch test reactions to MDBGN.

Recommendation to include methyldibromo glutaronitrile in the European standard patch test series

The preservative methyldibromo glutaronitrilc (MDBGN) is used non-occupationally and occupationally. High contact allergy rates have been reported when tested in consecutive dermatitis patients as well as clinical cases with allergic contact dermatitis. Up till now there has been no agreement on which patch test preparation to use to trace contact allergy to MDBGN. From the year 2005 on, MDBGN at 0.5% w/w in petrolatum is recommended for the European standard patch test series. The choice of 0.5% is based on consideration of rates of contact allergy, doubtful and irritant reactions, as well as on information on clinical relevance represented by results of a repeated open application test, and patch test concentrations to diagnose allergic contact dermatitis from MDBGN in individual cases.