Cross reactions between methyl methacrylate monomer and acrylic monomers presently used in acrylic nail preparations

Nail Cosmetics and Adornment

Nail polish is a nitrocellulose-based film that is modified to create a plastic shiny colored film that can be painted on the nail plate. The desire to develop a long-lasting pigmented film has resulted in the development of nail shellacs based on polymethyl methacrylate (PMMA) designed to polymerize on the nail plate. These films are chip resistant and long wearing, designed to last 3 to 4 weeks. Further polymer use has resulted in the ability to sculpt an elongated nail on the nail plate to create the appearance of long nails.

(Meth)Acrylate Occupational Contact Dermatitis in Nail Salon Workers: A Case Series

Background:

Recently, many cases of acrylate-associated allergic contact dermatitis have appeared among nail salon workers. Common acrylate-containing products in nail salons include traditional nail polish, ultraviolet-cured shellac nail polish, ultraviolet-cured gel nails, and press-on acrylic nails.

Methods:

Nail salon technicians seen in the occupational medicine clinic in 2015 and 2016 were identified, and their patch test results and clinical features were summarized. Patch testing was done with the Chemotechnique (Meth)Acrylate nail series, and either the North American Standard series or the North American Contact Dermatitis Group screening series.

Results:

Six patients were identified, all women, ages 38 to 58. Common presentations included erythematous dermatitis of the dorsa of the hands, palms, and forearms and fissures on the fingertips. Less common sites of eruptions included the periorbital region, cheeks, posterior ears, neck, sacral area, lateral thighs, and dorsa of the feet. All patients reacted to hydroxyethyl methacrylate, and 5 patients reacted to ethyl acrylate. Each patient also reacted to (meth)acrylates that are not found on either standard series, including ethyleneglycol dimethacrylate, 2-hydroxypropyl methacrylate, and 2-hydroxyethyl acrylate.

Conclusions:

The authors report 6 cases of allergic contact dermatitis to acrylates in nail technicians seen over the past year, representing a new trend in their clinic. These cases are reflective of a growing trend of nail technicians with allergic contact dermatitis associated with occupational (meth)acrylate exposure. Efforts to improve prevention are needed.

Final Report on Ethyl Methacrylate

Ethyl Methacrylate is the ester of ethyl alcohol and methacrylic acid used as the major structural monomer of artificial fingernail formulations that are cross-linked with one or more multifunctional methacrylates. Ethyl methacrylate monomer is polymerized rapidly and very little free monomer is available even during filing of the fingernails. The oral LD50 for rats ranged from 12.7 to 18.14 g/kg, with lesions in the respiratory system and hemoglobinuria observed in treated animals. Ocular, nasal, and respiratory tract irritation was observed in acute inhalation tests using rats. Very little toxicity was seen in subchronic studies using rabbits. Ethyl Methacrylate caused irritation and vehicle dependent sensitization in animals, but no photosensitization. Evidence of embryotoxic and teratogenic effects were observed in pregnant rats after intraperitoneal injection of Ethyl Methacrylate at a range of concentrations. Both positive and negative mutagenicity test data were found. Clinical testing showed little evidence of irritation, although case studies report allergic contact dermatitis as a result of exposure to Ethyl Methacrylate and related methacrylates with application of artificial fingernails. Occupational contact dermatitis from acrylates and methacrylates are also reported, with some evidence for cross-reactivity between the two chemical classes. Based on the sensitizing potential of this ingredient the CIR Expert Panel recommended that fingernail enhancement formulations with Ethyl Methacrylate be applied only by trained individuals and that the ingredient not be used in products intended for retail sale (currently, these products are believed to be sold only for application by a trained individual). Because of the low likelihood of significant exposure if such formulations are applied properly, the Expert Panel concluded that the ingredient is safe as used, with the caveat that skin contact should be avoided.

Contact and primary irritant dermatitis of the nail unit diagnosis and treatment

Contact dermatitis of the nail unit is not rare. The most common allergens are found in nail cosmetics such as enamel, sculptured nails, and preformed plastic tips. Toluene sulfonamide formaldehyde resin, acrylates, and ethylcyanoacrylate are the most common allergens. Along with a proper clinical history focusing on nail practices, a thorough understanding of the common allergens and patch testing are necessary to diagnose contact dermatitis. A discussion of the common allergens and irritants relevant to the nail unit will be presented.

Final report of the safety assessment of methacrylic acid

Methacrylic Acid is an organic acid used at concentrations between 50 and 88 percent to pretreat the nail and maximize the adhesion between the nail and artificial nail extender. Methacrylic Acid is readily absorbed through mucous membranes of the lungs, the gastrointestinal tract, and the skin; and is distributed to all major tissues. Oral LD50 values for rats ranged from 277 to 2260 mg/kg; acute toxicity symptoms included severe gastric irritation, gasping, labored respiration, prostration and hematuria. In a short-term inhalation study, rats exposed to Methacrylic Acid at 1300 ppm showed nose and eye irritation and weight loss, while necropsy results and blood and urine tests were normal. Methacrylic Acid is an ocular toxicant in animals. Undiluted Methacrylic Acid is corrosive to the skin of rabbits and guinea pigs. Exposure as limited as 3 minutes can cause severe erythema and slight to moderate edema. Exposure from 15 minutes to 24 hours under occlusive patches can cause marked to severe discoloration, slight to severe subcutaneous hemorrhages, necrosis, ulcerations, severe erythema, edema and concave eschar. Methacrylic Acid was irritating and caused strong rubefaction and scab formation in a guinea pig maximization test at challenge concentrations from 10 to 100 percent. It was difficult to determine if the results were type IV hypersensitivity reactions or simple irritation. In three other studies, guinea pigs were not sensitized. Methacrylic Acid was not a reproductive/developmental toxicant in rats or mice. Methacrylic Acid was negative in Salmonella typhimurium mutagenicity tests using strains TA98, TA100, TA1535 and TA1537 both with and without metabolic activation, but was positive in a DNA-cell-binding assay. Case reports involving Methacrylic Acid often involve children. Effects from ingestion include drooling, gagging, and vomiting. Children exposed to Methacrylic Acid as a result of accidental spills caused first and second degree burns to the eyes, face, hands, arms, and chest. The Consumer Product Safety Commission has required child-resistant packaging for liquid household products containing more than 5 percent Methacrylic Acid (weight-to-volume) in a single package. Since Methacrylic Acid is an extremely corrosive chemical, a primary concern about its use as a cosmetic ingredient was the ability to limit exposure to the nail when pretreating the nail prior to application of an artificial nail extender. A videotape presentation demonstrated that a trained professional could use a small applicator brush to dab a limited volume of Methacrylic Acid only to the center of the nail, allowing the monomer liquid to diffuse down the nail without any exposure to the skin. There were no available data to demonstrate that an individual consumer could apply Methacrylic Acid and avoid inadvertent skin contact. In order to minimize any exposure to the acid, the Expert Panel concluded that nail primers containing Methacrylic Acid could be used safely by trained individuals instructed to ensure that there be no contact with the skin. The CIR Expert Panel recognized that there are no chronic inhalation toxicity data on Methacrylic Acid, but was concerned that inhalation of Methacrylic Acid could affect the respiratory tract. Since the inhalation exposure time is significantly increased in a commercial setting, the Panel was more concerned about the safety of the nail technician than the consumer. The Expert Panel concluded that the current NIOSH recommended exposure limit of 20 ppm would provide adequate protection.

Final report of the safety assessment of methacrylate ester monomers used in nail enhancement products

Methacrylate ester monomers are used in as artificial nail builders in nail enhancement products. They undergo rapid polymerization to form a hard material on the nail that is then shaped. While Ethyl Methacrylate is the primary monomer used in nail enhancement products, other methacrylate esters are also used. This safety assessment addresses 22 other methacrylate esters reported by industry to be present in small percentages as artificial nail builders in cosmetic products. They function to speed up polymerization and/or form cross-links. Only Tetrahydrofurfuryl Methacrylate was reported to the FDA to be in current use. The polymerization rates of these methacrylate esters are within the same range as Ethyl Methacrylate. While data are not available on all of these methacrylate esters, the available data demonstrated little acute oral, dermal, or i.p. toxicity. In a 28-day inhalation study on rats, Butyl Methacrylate caused upper airway irritation; the NOAEL was 1801 mg/m3. In a 28-day oral toxicity study on rats, t-Butyl Methacrylate had a NOAEL of 20 mg/kg/day. Beagle dogs dosed with 0.2 to 2.0 g/kg/day of C12 to C18 methacrylate monomers for 13 weeks exhibited effects only in the highest dose group: weight loss, emesis, diarrhea, mucoid feces, or salivation were observed. Butyl Methacrylate (0.1 M) and Isobutyl Methacrylate (0.1 M) are mildly irritating to the rabbit eye. HEMA is corrosive when instilled in the rabbit eye, while PEG-4 Dimethacrylate and Trimethylolpropane Trimethacrylate are minimally irritating to the eye. Dermal irritation caused by methacrylates is documented in guinea pigs and rabbits. In guinea pigs, HEMA, Isopropylidenediphenyl Bisglycidyl Methacrylate, Lauryl Methacrylate, and Trimethylolpropane Trimethacrylate are strong sensitizers; Butyl Methacrylate, Cyclohexyl Methacrylate, Hexyl Methacrylate, and Urethane Methacrylate are moderate sensitizers; Hydroxypropyl Methacrylate is a weak sensitizer; and PEG-4 Dimethacrylate and Triethylene Glycol Dimethacrylate are not sensitizers. Ethylene Glycol Dimethacrylate was not a sensitizer in one guinea pig study, but was a strong sensitizer in another. There is cross-reactivity between various methacrylate esters in some sensitization tests. Inhaled Butyl Methacrylate, HEMA, Hydroxypropyl Methacrylate, and Trimethylolpropane Trimethacrylate can be developmental toxicants at high exposure levels (1000 mg/kg/day). None of the methacrylate ester monomers that were tested were shown to have any endocrine disrupting activity. These methacrylate esters are mostly non-mutagenic in bacterial test systems, but weak mutagenic responses were seen in mammalian cell test systems. Chronic dermal exposure of mice to PEG-4 Dimethacrylate (25 mg, 2 x weekly for 80 weeks) or Trimethylolpropane Trimethacrylate (25 mg, 2 x weekly for 80 weeks) did not result in increased incidence of skin or visceral tumors. The carcinogenicity of Triethylene Glycol Dimethacrylate (5, 25, or 50%) was assessed in a mouse skin painting study (50 microl for 5 days/week for 78 weeks), but was not carcinogenic at any dose level tested. The Expert Panel was concerned about the strong sensitization and crossor co-reactivity potential of the methacrylate esters reviewed in this report. However, data demonstrated the rates of polymerization of these Methacrylates were similar to that of Ethyl Methacrylate and there would be little monomer available exposure to the skin. In consideration of the animal toxicity data, the CIR Expert Panel decided that these methacrylate esters should be restricted to the nail and must not be in contact with the skin. Accordingly, these methacrylate esters are safe as used in nail enhancement products when skin contact is avoided.

Amended final report on the safety assessment of ethyl methacrylate

Ethyl Methacrylate is a methacrylate ester used as a chemical additive in artificial fingernail enhancement products. These products may be applied by trained professionals or be provided directly to consumers with instructions for use. Ethyl Methacrylate readily polymerizes and rapidly reacts with multifunction methacrylates to form a highly cross-linked polymer. The oral LD(50) of Ethyl Methacrylate for rats ranged from 12.7 to 18.14 g/kg. In acute studies with rats, hemoglobinuria and respiratory tract lesions were observed. Animal studies indicate that Ethyl Methacrylate is a skin irritant and sensitizer. In some cases the results were dependent on the vehicle. Evidence of embryotoxicity and teratogenicity were observed in rats injected intraperitoneally with 0.1223 to 0.4076 ml/kg Ethyl Methacrylate. Positive evidence of mutagenicity was observed in the L5178Y mouse lymphoma cell assay, but not in two Ames tests. Case reports cite examples of individuals suffering allergic contact dermatitis from exposure to Ethyl Methacrylate and related methacrylates, and some degree of cross-reactivity appears to exist between widely used acrylates and methacrylates. Information from several clinical registries of sensitization reactions to various agents reported that Ethyl Methacrylate is a sensitizer, but not a potent one. Because Ethyl Methacrylate monomer is short-lived in the normal course of using artificial fingernail-enhancement products, the primary hazard is expected to be inadvertant skin contact. In order to avoid sensitization, it is necessary to avoid skin contact. It is recommended that fingernail-enhancement products containing Ethyl Methacrylate include directions to avoid skin contact because of the sensitizing potential. Based on the available data on the formulation of nail products containing this ingredient, it is concluded that Ethyl Methacrylate is safe as used, when application is accompanied by directions for use as above.

Nail cosmetic issues

Nail cosmetics are a part of good hygiene and self adornment. These cosmetics can provide solutions to problems involving the nail plate and also can create disease. This article provides a diagnosis and treatment-oriented approach to nail cosmetic issues.

Allergic contact dermatitis to artificial fingernails prepared from UV light-cured acrylates

BACKGROUND

Contact dermatitis from artificial nails made from self-curing acrylic resins is occasionally reported. Recently, UV light-cured products introducing new acrylics have become available.

OBJECTIVE

Our purpose was to identify relevant allergens in commercial light-curing products by patch tests and to evaluate the efficacy of "hypoallergenic" products by inclusion into the test series.

METHODS

Patients wearing photobonded acrylic nails who had perionychial and subonychial eczema were patch tested with an acrylate battery and "hypoallergenic" commercial products.

RESULTS

Triethyleneglycol dimethacrylate, hydroxyfunctional methacrylates, and (meth)-acrylated urethanes proved to be relevant allergens in photobonded nail preparations. Methacrylated epoxy resin sensitization was not observed. All "hypoallergenic" products provoked positive reactions.

CONCLUSION

The omission of irritant methacrylic acid in UV-curable products does not reduce the high sensitizing potential of new acrylates. In contrast to the manufacturers' declarations, all "hypoallergenic" products continue to include acrylate functional monomers and therefore continue to cause allergic sensitization.

Evaluation of patch test results with denture material series

791 patients, among them 59 dental technicians and 732 other patients, were tested with the denture material series (DMS) recommended by the German Contact Dermatitis Research Group (DKG) in the hospitals of the Information Network of Departments of Dermatology (IVDK) between January 1990 and July 1993. Most frequently, positive reactions occurred to cadmium chloride in both groups. However, there was no evidence at all for relevance of these reactions. Benzoyl peroxide (BPO) ranked 2nd in patch test positivity. Although not statistically significant, reactions were more frequent in dental technicians, who might be exposed to BPO the in working environment. Methyl methacrylate (MMA) and triethylene glycol dimethacrylate (TEGDMA) were common sensitizers in dental technicians but not in other patients. This finding, too, has its explanation in the working process of manufacturing dental prostheses.

Occupational skin diseases in dental laboratory technicians. (I). Clinical picture and causative factors

In Germany, occupational skin disease (OSD) in dental technicians (DT) has been steadily rising in recent years and causing considerable costs for medical care and rehabilitation. Our objective in this study was to: (i) examine affected workers; (ii) perform patch tests to identify causative agents; (iii) develop strategies of prevention. 7 dental laboratories were inspected as to materials used, working habits, safety regulations, etc. A computer data base was developed for products (trade name, active ingredient, additives, etc.). A questionnaire regarding development of OSD was sent out to 1132 dental technicians (45 questions). 55 DT with suspected OSD were examined and patch tested with the standard series, an extensive series of methacrylates, and own materials. Working conditions, and knowledge of potential hazards, varied greatly in the laboratories visited. The safety data sheets of working materials were of little use and required supplementation by the computer data base, which provided rapid access to allergological information (e.g., type of acrylate, concentration). In the questionnaire (173 answers), 36% reported skin lesions attributed to work and 1/3 suspected plastic materials as their primary cause. Among the 55 DT examined, allergic contact dermatitis was diagnosed in 63.6% and irritant contact dermatitis in 23.6%. Most of the allergens identified (74%) were found in plastic materials (methyl methacrylate (MMA), 9 patients (16%); 2-hydroxyethyl methacrylate (2-HEMA), 18 patients (33%); ethyleneglycol dimethacrylate (EGDMA), 15 patients (27%)). In 16 patients, multiple sensitizations to various methacrylates were found. The fingertips were primarily involved in allergic contact dermatitis (93%), whereas in irritant contact dermatitis, the dorsa of the fingers (especially of the dominant hand) were affected (80%). 9 patients also showed lesions on the face, neck and forearms. The main irritant factors included wet work, contact with plaster, mechanical friction and thermal changes. Based on experience with DT, various preventive measures have been tried and found to be effective (reduction of skin contact, 4H Gloves, etc.). In conclusion, better knowledge of OSD in dental laboratories (in physicians, DT and their employers) would lead to a reduced rate of new cases.

Adverse contact reactions to sculptured acrylic nails: 4 case reports and a literature review

4 cases with differing presentations of contact allergy to acrylates in sculptured acrylic nails are presented. These reactions include nail fold, fingertip and hand dermatitis, face and neck dermatitis, dystrophic nail changes and paraesthesia. We discuss acrylic nails and review the previously published reactions to acrylates in acrylic nails.

Systemic paraphenylenediamine (PPD) poisoning: a case report and review

A case of suicidal poisoning with paraphenylenediamine (PPD) is reported. The patient presented with typical features of severe oropharyngeal oedema and rhabdomyolysis. He suffered sudden cardiac death within 4 hours of admission despite full supportive treatment. The diagnosis was only established after his death. Systemic poisoning with paraphenylenediamine (PPD) is rare in western countries, and therefore a high degree of awareness and circumstantial evidence is required to make an early diagnosis. The classical and other less commonly reported features of this poisoning are discussed. There is no specific antidote available but some guidelines for management of such a case are reviewed.

Occupational allergic contact dermatitis caused by exposure to acrylates during work with dental prostheses

Between 1974 and 1992, we were consulted by 4 patients (an orthodontist, 2 dental technicians and a dental worker trained in-house) who had developed occupational allergic contact dermatitis from working with dental prostheses. All patients had positive allergic patch test reactions to methyl methacrylate (MMA), the acrylate which is the most widely used in work with prostheses. All but the orthodontist also reacted to dimethacrylates, which are used in cross-linked dental prostheses. The last patient, investigated in 1992, had been exposed mainly to light-cured acrylics, which are similar in composition to dental composite resins. These acrylics, only recently introduced into prosthetic work, contain more potent acrylic sensitizers than MMA. Accordingly, dental personnel working with prostheses may face a higher risk of sensitization than previously. To detect cases of occupational allergic contact dermatitis, we suggest that patients working with dental prostheses should be patch tested with MMA, 2-hydroxyethyl methacrylate, dimethacrylates, epoxy acrylates and urethane acrylates.

Occupational contact dermatitis in 2 dental technicians

2 dental technicians, both with chronic hand eczema, reported worsening from the use of 2 products containing methyl methacrylate, employed in manufacturing acrylic prostheses. Patch tests in both patients gave positive reactions to methyl methacrylate, ethylene glycol dimethacrylate and products employed in manufacturing acrylic prostheses (2% and 5% pet.). On the basis of results subsequently obtained from patch tests carried out with pieces of glove interposed between the skin and the allergens (methyl methacrylate and products employed), we advised our patients still to use latex gloves during work. Follow-up after 1 year showed complete regression of the dermatitis in 1 case and considerable improvement in the other.

The sensitizing capacity of multifunctional acrylates in the guinea pig

The multifunctional acrylates used in ultraviolet (UV) curable resins act as cross-linkers and "diluents". They are usually based on di(meth)acrylate esters of dialcohols or tri- and tetra-acrylate esters of polyalcohols. In UV-curable coatings, the most commonly used are pentaerythritol triacrylate (PETA), trimethylolpropane triacrylate (TMPTA) and 1,6-hexanediol diacrylate (HDDA). In other uses, such as dental composite resin materials, the dimethacrylic monomers based on n-ethylene glycol are the most useful. The sensitizing capacity of various multifunctional acrylates and their cross-reactivity pattern have been investigated with the guinea pig maximization test. The tests show that BUDA (1,4-butanediol diacrylate) and HDDA are moderate to strong sensitizers and that they probably cross-react with each other. The n-ethylene glycol diacrylates and methacrylates tested are weak or non-sensitizers. Tripropylene glycol diacrylate (TPGDA) is a moderate and neopentyl glycol diacrylate (NPGDA) a strong sensitizer, whereas neopentyl glycol dimethacrylate is a non-sensitizer. The commercial PETA is a mixture of pentaerythritol tri- and tetra-acrylate (PETA-3 and PETA-4). PETA-3 is a much stronger sensitizer than PETA-4. Simultaneous reactions were seen between PETA-3, PETA-4 and TMPTA. The oligotriacrylate OTA 480 is a moderate sensitizer, but no concomitant reactions were seen with PETA-3, PETA-4 or TMPTA. Of the multifunctional acrylates tested, the di- and triacrylic compounds should be regarded as potent sensitizers. The methacrylated multifunctional acrylic compounds are weak or non-sensitizers.

Cross-reaction patterns in guinea pigs sensitized to acrylic monomers

The cross-reaction patterns of selected acrylate and methacrylate esters were investigated using the guinea pig maximization test. Methacrylates were less potent sensitizers than acrylates. Cross-sensitization was found between (meth)acrylates with closely related core structures, most extensively between hydroxyethyl and hydroxypropyl congeners. The importance of considering not only the functional group but also the core structure when assessing potential interactions was emphasized as butanedioldiglycidylether, hexamethylenediisocyanate and hexanedioldiacrylate--all with linear 6-atom cores and different functional group--cross-reacted.

Cross reaction pattern of 26 acrylic monomers on guinea pig skin

The cross reaction pattern of acrylic monomers was investigated in 20 groups of animals sensitized to a different acrylic monomer. Animals sensitized to one monoacrylate tend to react to other monoacrylates. Reactions to corresponding monomethacrylates (same alcohol group in the ester) or other monomethacrylates did not occur. Some reactions to di(meth)acrylates were observed. A number of animals sensitized to one monomethacrylate reacted to some other monomethacrylates and to monoacrylates. Reactions to di(meth)acrylates were observed. Animals sensitized to di(meth)acrylates showed hardly any positive cross reaction. A universal screening allergen to detect acrylic monomer sensitizations does not exist. The composition of (industrial) products should be made accessible to the occupational dermatologist in order to prevent the undesirable situation in which a patient suspected of having an acrylic monomer sensitization must be tested with a large series of potent allergens in order to detect the real origin of the sensitization.

Secondary acrylamides in Nyloprint printing plate as a source of contact dermatitis

Several chemically pure fractions have been isolated from Nyloprint printing plates. 5 of the fractions elicited positive patch test reactions in 7 Nylonprint allergic printers. 4 of the 5 components were analysed by means of nuclear magnetic resonance, infrared spectrophotometry, mass spectrometry and elemental analysis. The fractions were identified as N,N'-methylene-bis-acrylamide. N,N'-[oxybis(methylene)]bis-2-propenamide, N,N'-[1,2-ethanediylbis(oxymethylene)]-2-propenamide, and a new compound N-[(2-hydroxyethoxy)-methyl]-2-propenamide. All of the analysed fractions have the common feature of being secondary acrylamides.