Recommended patch test concentrations for preservatives, biocides and antimicrobials

102 cases of sensitization to an antiseptic containing chlorhexidine digluconate/benzalkonium chloride/benzyl alcohol with different profiles of sensitization in adults and children

BACKGROUND

An aqueous antiseptic containing "chlorhexidine digluconate /benzalkonium chloride /benzyl alcohol" (CBB) is widely used in France. The only previous documented study dealing with allergic contact dermatitis to this antiseptic is one small case series in children. The French Vigilance Network for Dermatology and Allergy (REVIDAL-GERDA) has collected many cases in the last few years.

OBJECTIVES

To evaluate the clinical and sensitization profiles of patients diagnosed with allergic contact dermatitis to CBB.

METHODS

We performed a retrospective study of patients with contact dermatitis to CBB and positive tests to CBB and/or at least one of its components. All patients had to be tested with all components of CBB.

RESULTS

Seventy-one adults and thirty-one children were included. The lesions were extensive in 63 % of patients and 55% had delayed time to diagnosis. CBB patch tests were positive in 93.8% of cases. The allergen was identified in 97% of patients, mainly benzyl alcohol in adults (81.7%), and chlorhexidine digluconate in children (54.8%). 32.4% of the patients were sensitized to several components.

CONCLUSION

CBB is a cause of allergic contact dermatitis at all ages. The antiseptic's components should be tested. The sensitization profile seems to be different between adults and children. This article is protected by copyright. All rights reserved.

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

Characteristics of patch test reactions to common preservatives incorporated in petrolatum and water, respectively

BACKGROUND

The irritant properties of some preservatives and the use of water as the patch test vehicle for some of them call for a critical evaluation of patch test reactions to preservatives.

OBJECTIVES

To examine the association between test vehicle (petrolatum versus water) or the patients' age and history of atopic dermatitis, respectively, and certain patterns of reaction to preservatives.

PATIENTS/METHODS

Data of 34,631 patients tested in 34 centres with 11 common preservatives were retrospectively analysed. The dynamic reaction patterns, reaction indices (RIs) and positivity ratios (PRs) were statistically evaluated.

RESULTS

All preservatives yielded more crescendo reactions in older than in younger patients. For 10 of 11 preservatives, the percentage of crescendo reactions was slightly higher in patients without a history of atopic dermatitis, and for 10 of 11 agents the RI was higher in patients with a positive history of atopic dermatitis. No consistent vehicle-related effects on reaction characteristics were found. Chlorhexidine digluconate 0.5% in water and sodium benzoate 5% in petrolatum had the lowest RIs, highest PRs, and lowest proportions of crescendo reactions.

CONCLUSIONS

Water as a vehicle is unlikely to affect the reaction patterns of preservatives. The generally used patch test preparations of chlorhexidine digluconate and sodium benzoate need improvement.

The sensitizing potential of various biocides in the guinea pig maximization test

Biocides are chemicals used as preservatives added to most cosmetics and toiletries and to industrial water-based products such as cutting fluids, paints and glues. There are numerous biocide formulations used in water-based metalworking fluids. All these products, characterized by a low molecular weight, can react with endogenous proteins and may induce allergic contact dermatitis. Thus, numerous reports on occupational allergic contact dermatitis have been published. The purpose of this experimental study was to compare the sensitizing potential of the various classes of biocides used in metalworking fluids by means of the maximization test of Magnusson & Kligman. The results show that, from the 9 samples tested, 7 biocides induced sensitization varying in grade from moderate to strong, while 2 benzisothiazoline-based samples did not induce allergic contact dermatitis.

Skin sensitization risk assessment: a comparative evaluation of 3 isothiazolinone biocides

Many of the chemicals in common use possess, to some degree, a capacity to cause skin sensitization. Consequently, it is important to conduct a thorough and accurate risk assessment when it can be anticipated that such chemicals are likely to come into contact with human skin. Such risk assessments must consider the nature and extent of dermal exposure together with the sensitizing potency of the chemical. Whilst the exposure elements of the risk assessment process are often well understood, or can at least be reasonably predicted on the basis of the proposed usage of the chemical, the determination of skin sensitizing potency may be problematic. In this paper, we describe an approach to the determination of relative potency of 3 isothiazolinone biocides. Initially, the local lymph node assay (LLNA) provides an estimate of relative sensitizing potency. Where appropriate, this can be followed by confirmatory testing in the human repeat insult patch test (HRIPT). The data generated reveal that (chloro)methyl isothiazolinone (CMI) is a significantly stronger sensitizer than either methyl trimethylene isothiazolinone (MTI) or benzisothiazolinone (BIT). Furthermore, both the LLNA and the HRIPT data show consistently that BIT is a somewhat weaker skin sensitizer than MTI. As an important additional component of the safety evaluation, the ability of these sensitizing isothiazolinones to cross-react has been considered; the data indicate that the more weakly sensitizing isothiazolinones do not elicit allergic reactions in subjects sensitized to MCI. The implications for use of these biocides in various product types are discussed.

Managing the excited skin syndrome: patch testing hyperirritable skin

Inflammation-modulating phenomena (IMPs), humoral and cellular, fluctuate during the course of irritant and allergic contact dermatitis influencing irritability of the skin. The patch test procedure is a biological assay, a titration of responses of IMPs which can produce hyporeactivity or hyperirritability of the skin of patients who have dermatitis (PDs) and a single patch test is a 'snapshot' of the tempo of an evolving process. The excited skin syndrome (ESS) refers to hyperirritability from clinical and patch test dermatitis creating false-positive patch test reactions which are not reproducible when dermatitis and IMPs have subsided. During ESS, the threshold for irritancy decreases and irritant reactions increase. Patch test concentrations should be determined and ESS investigated in PDs having enhanced IMPs, not in 'normal' individuals, and if a patch test result is important to a patient the test should be performed more than once. Variable reproducibility is inherent in the patch test method, but ESS can be managed by appropriate testing and retesting, and search for relevance.

1,2-Benzisothiazolin-3-one (Proxel): irritant or allergen? A clinical study and literature review

The isothiazolinone, 1,2-benzisothiazolin-3-one (Proxel), is a popular preservative, as well as a skin sensitizer and irritant. Patch test studies have been performed with different concentrations and vehicles. The current suggested patch test concentration is 0.1% BIT in petrolatum (pet). This article evaluates the effects of patch testing at this concentration and reviews the current literature. An irritancy patch test was performed on 56 controls, using BIT in concentrations of 0.002% and 0.05% in aqueous dipropylene glycol (Proxel GXL) and 0.1% in pet. 10 had positive readings at 4 days with 0.1% BIT in petrolatum, 9 of which were negative at retest. 0.1% BIT is, therefore, irritant and not a suitable concentration for patch testing. Literature review revealed 15 patch test studies, with varying testing techniques. Additional studies with adequate controls and experimental tests should be invaluable in furthering our insight into BIT sensitization and irritation.

Contact allergy to the active ingredients of Bioban P 1487

Bioban P 1487, consisting of the 2 active ingredients 4-(2-nitrobutyl)-morpholine (M) and 4,4'-(2-ethyl-2-nitro-1,3-propanediyl)-bis morpholine (DM), is a preservative recommended for mental working fluids. The aims of this study were to assess the frequency of contact allergy to Bioban P 1487, when added to a standard patch test series, as well as to test the individual active ingredients in patients sensitized to Bioban P 1487. Of the patients consecutively tested, 1.5% reacted positively to Bioban P 1487. Positive test reactions were noted in only 4 of 12 Bioban P 1487-sensitized patients tested with the individual active ingredients. Both active ingredients are contact sensitizers, but in most patients with this contact allergy it remains difficult to identify the sensitizing hapten.

Frequency of sensitization to 13 common preservatives in Switzerland. Swiss Contact Dermatitis Research Group

From February 1989 to January 1990, the Swiss Contact Dermatitis Research Group conducted a 1-year study to examine the frequency of sensitization to a series of 13 common preservatives. A group of 2295 consecutive outpatients with suspected allergic contact dermatitis (age range 7-90 years, with a mean age of 42; 911 males, 1384 females) was tested. The %s of positive reactions to the preservatives studied are as follows, in descending order: formaldehyde 5.7%, benzalkonium chloride 5.5%, Kathon CG 5.5%, thimerosal 4.2%, chlorhexidine digluconate 2.0%, DMDM hydantoin 1.7%, paraben mix 1.7%, chloroacetamide 1.5%, Bronopol 1.2%, imidazolidinyl urea 1.0%, quaternium 15 1.0%, triclosan 0.8%, 2,4-dichlorobenzyl alcohol 0.4%. These relatively high values suggest a heavy exposure of the Swiss population to topical preservatives. Compared to previous studies, the sensitization rate to Kathon CG has stabilized in Switzerland over the last 2 years. Sensitization to formaldehyde portrayed impressive geographical variation, with sensitization rates up to 9% in western and only 3% in eastern Switzerland. The low sensitization rate to parabens argues for their inclusion in a medicament or preservative series, rather than in the standard series.

Contact allergens in registered cleaning agents for industrial and household use

Cleaning work is a common cause of both irritant and allergic contact dermatitis. Cleaning agents for industrial and household use are registered in the Danish Product Register Data Base (PROBAS) according to a special notification rule issued by the Danish Environmental Protection Agency. About 2350 registered washing and cleaning agents containing about 1250 different chemical substances were marketed in Denmark in February 1992. The occurrence of 49 contact allergens in 16 different product types within washing and cleaning agents were listed. Preservatives and surface active agents made up the main part of contact allergens. Isothiazolinones and formaldehyde releasers were the most commonly registered preservatives, and coconut diethanolamide the most commonly registered surface active agent. The major product types registered as containing contact allergens were general cleaners, skin cleaners, hair shampoos, and floor polishes.

Identification of formaldehyde releasers and occurrence of formaldehyde and formaldehyde releasers in registered chemical products

Substances referred to as formaldehyde releasers were identified on review of the literature. Information on product categories and typical concentrations for chemical products containing formaldehyde and formaldehyde releasers was obtained from the Danish Product Register Data Base (PROBAS). As of February 1992, 62,000 products were registered in PROBAS, 30,900 of these with information on composition and product category. Among the components of these products, 19 of the 22 identified formaldehyde releasers were found. The number of products registered with each formaldehyde releaser varied from 4 to 171, with cleaning agents, soaps, shampoos, paint/lacquers, and cutting fluids as the most frequent product categories. The most frequently registered formaldehyde releasers were bromonitropropanediol, bromonitrodioxane, and chloroallylhexaminium chloride. Formaldehyde itself was registered in 1,781 products, and was found in all product categories included in the study. It is concluded that products for industrial use as well as household and personal care products should be considered as sources of formaldehyde exposure. The use of unsystematic chemical names in literature is discussed.

The frequency of reactions to sunscreens: results of a longitudinal population-based study on the regular use of sunscreens in Australia

Six-hundred-and-three people aged 40 or more years, from Maryborough in central Victoria, were enrolled in a randomized longitudinal study, which required daily application of either a SPF 15+, broad-spectrum, water-resistant sunscreen cream or the cream base without the active ingredients. The study duration was 7 months, from September 1991 until April 1992. One-hundred-and-fourteen (18.9%) of these subjects developed an adverse reaction to the cream they were applying. Patch testing, photopatch testing and scratch testing with the ingredients of the creams revealed that only a small proportion (< 10%) of the inflammatory eruptions were allergic in nature. None of the people tested was allergic to the sunscreen active ingredients. History and examination findings, where available, suggested that the majority of adverse responses were consistent with an irritant reaction, both to the sunscreen preparation and the base cream control. A higher than expected proportion of the people who developed an adverse reaction had a personal history consistent with atopy. Other reactions included acneiform eruptions and contact urticaria. A frequency of reactions to sunscreen preparations of over 15% means that further work is necessary to improve both the formulation of such products, and the manner and conditions under which they are used, to ensure satisfactory compliance.

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.

Allergic contact dermatitis from the preservative 1,2-benzisothiazolin-3-one (1,2-BIT; Proxel): a case report, its prevalence in those occupationally at risk and in the general dermatological population, and its relationship to allergy to its analogue Kathon CG

Occupational contact allergy to 1,2-benzisothiazolin-3-one (1,2-BIT, Proxel) is analysed. This compound is widely used in industry as a preservative in water-based solutions such as pastes, paints and cutting oils. The optimal concentration for patch testing proved to be 0.4 g/l (0.04%) in water. In 4 out of 17 patients (23%) at occupational risk (painters, paper-hangers), contact allergy to 1,2-BIT was found. Of 556 consecutive dermatological patients without clear occupational risk, 10 (1.8%) showed positive patch tests to 1,2-BIT; in 3 patients 1,2-BIT contact allergy was related to domestic paper-hanging. Although the chemical structure of 1,2-BIT shows some analogy with the preservative Kathon CG, true cross-sensitivity was found to be unlikely.