2014 Volume 56 Issue 3 Pages 229-234
Backgrounds: Two-component acrylic resin used in nail art and dentistry can cause allergic contact dermatitis (ACD), but only a few reports from Japan have been published. Cases: A 35-year-old female manicurist (case 1) and 30-year-old female dental hygienist (case 2) were diagnosed with ACD caused by ethyl methacrylate and methyl methacrylate in a liquid monomer of two-component acrylic resin respectively. Case 1 was sensitized from direct skin contact with nail art acrylic products, which could have been avoided, and gave up both being a manicurist and a user. Onset in case 2 occurred when she started to work as an apprentice. She had believed that the cause of her symptoms was use of disposable natural rubber gloves, not a liquid monomer penetrating through her gloves, until she was patch tested positive to (meth)acrylates and liquid monomer. Conclusions: To prevent sensitization, it should be emphasized in occupational training in both specialties that there should be no direct contact with acrylic products and that disposable gloves do not have sufficient protecting properties.
(J Occup Health 2014; 56: 229-234)
Acrylic products are widely used in various industries as glues, inks, paints, varnishes, lacquers, coatings, etc. and well-known to cause allergic contact dermatitis (ACD)1). However, in Japan, only a few cases of occupational ACD due to acrylic products used in industries have been reported2–4). The use of artificial nails is recently becoming so popular among Japanese women. One major health hazard associated with artificial nails is contact allergy due to (meth)acrylates. Two kinds of artificial nails, pre-sculptured plastic tips and sculptured nails, are often used. The former have already been shaped and are just glued onto nails, and the latter are sculptured using two-component acrylic resin or ultraviolet-cured acrylic resin5). The main constituents of the glue and the sculptured nail resins are (meth)acrylates. Dentistry workers are also heavily exposed to (meth)acrylates, which are used for dental fillings, glues, and dentures1, 6). In dental personnel, the prevalence of ACD was estimated to be about 1%. Among dentists, about 2% were reported to have allergic reactions to (di)methacrylates6).
Here two cases of ACD due to two-component acrylic resin in a manicurist and a dental hygienist are reported. Both causative two-component acrylic resins consisted of acrylic polymer powder and acrylic monomer liquid, and the latter causes ACD. Recommendations for patch test substances for diagnosis and preventive measures are also presented.
Case 1: A 35-year-old female noticed itching at the tips of her fingers when touching artificial nail materials three months after she started to use them. She consulted a dermatologist, complaining of severe itchy eczema around her nails and onycholysis one year later (Fig. 1). The constituents of her nail art products are shown in Table 1. She was patch tested with the four kinds of products (1 and 2% petrolatum (pet.) of liquid monomer and 1 and 5% pet. of powder, primer, and remover) (Table 1) and 6 kinds of methacrylates (Almirall Hermal, Reinbek, Germany) (Table 2). Readings were performed 1 day and 5 days after occlusion for 2 days (day 3 and day 7) according to the International Contact Dermatitis Research Group (ICDRG) standard. The results of patch tests on day 7 are shown in Tables 1 and 2. Her eczema was diagnosed as ACD caused by the liquid monomer of the two-component acrylic resin, primer and remover. It disappeared under treatment with topical corticosteroid, but numbness at the tips of her fingers continued for the next month. She experienced recurrence of her symptoms after she used the same artificial nail materials again on one of her customers; therefore, she gave up using those substances.
Eczema with vesicles and scales on finger tips (case 1).
| Products | Constituents | Conc. | Patch test results** (day 7) | |
|---|---|---|---|---|
| Two-component acrylic resin | ||||
| Liquid monomer | Ethyl methacrylate | 90% | ||
| Benzophenone | 9.09% | 1% pet. + | ||
| N,N-Dimethyl-P-toluidine | 0.91% | 2% pet. + | ||
| Powder | Acrylate copolymer | 99.90% | ||
| Benzoyl peroxide | 0.07% | 1% pet. − | ||
| Aluminum powder | 0.01% | 5% pet. − | ||
| Primer | Acetone | 90% | ||
| PMGDM* | 9% | 1% pet. + | ||
| Glycerol dimethacrylate | 1% | 5% pet. + | ||
| Remover | Methyl ethyl ketone | 55% | ||
| Methyl isobutyl ketone | 29% | 1% pet. − | ||
| Isopropyl alcohol | 10% | 5% pet. + | ||
| Ethyl acetate | 6% | |||
| Substances | Abbreviation | Conc. (in pet.) | Case 1 (day 7) | Case 2 (day 3) |
|---|---|---|---|---|
| (Meth)acrylates | ||||
| 2-Hydroxyethyl methacrylate | 2-HEMA | 1% | + | +++ |
| Methyl methacrylate | MMA | 2% | − | ++ |
| Ethyl methacrylate | EMA | 2% | nt | ++ |
| Tetrahydrofurfuryl methacrylate | THFMA | 2% | nt | ?+ |
| n-Butyl methacrylate | BMA | 2% | nt | − |
| 2-Hydroxypropyl methacrylate | 2-HPMA | 2% | nt | − |
| Bisphenol A glycerolate dimethacrylate | Bis-GMA | 2% | − | − |
| Bisphenol A dimethacrylate | Bis-MA | 2% | nt | − |
| Ethyleneglycol dimethacrylate | EGDMA | 2% | ++ | +++ |
| Triethyleneglycol dimethacrylate | TREGDMA | 2% | − | − |
| Urethane dimethacrylate | UDMA | 2% | − | − |
| 1,3-Butanediol dimethacrylate | BUDMA | 2% | nt | − |
| Ethyl acrylate | EA | 0.1% | nt | ?+ |
| Butyl acrylate | BA | 0.1% | nt | + |
| 2-Hydroxyethyl acrylate | 2-HEA | 0.1% | nt | ++ |
| 2-Hydroxypropyl acrylate | 2-HPA | 0.1% | nt | − |
| 2-Ethylhexyl acrylate | 2-EHA | 0.1% | nt | − |
| Triethyleneglycol diacrylate | TREGDA | 0.1% | nt | − |
| 1,6-Hexanediol diacrylate | HDDA | 0.1% | nt | − |
| Trimethylolpropane triacrylate | TMPTA | 0.1% | nt | − |
| Ethyl cyanoacrylate | ECA | 10% | nt | − |
| Additives | ||||
| Benzoyl peroxide | 1% | nt | − | |
| N,N-dimethyl-p-toluidine | 2% | nt | − | |
| Metals | ||||
| Nickel sulphate | 2.5% | nt | − | |
| Gold sodium thiosulfate | 0.5% | nt | − | |
| Cobalt chloride | 1% | nt | − | |
| Ammonium tetrachloroplatinate | 0.25% | nt | − | |
| Amalgam alloy metals (Ag 8.2%, Cu 5.6%, Sn 6.2%) | 20% | nt | − | |
| Amalgam, non-gamma 2 (53% alloy/47% Hg) | 5% | nt | − | |
| Palladium chloride | 1% | nt | − | |
| Tin-II-chloride | 0.5% | nt | − | |
| Titanium-IV-oxide | 0.1% | nt | − | |
Conc., concentration; pet., petrolatum; nt, not tested, *Readings were performed according to the ICDRG standard.
Case 2: A 30-year-old female dental hygienist developed hand eczema when she started an apprentice at the age of 20 in which she wore powdered latex gloves washed her hands frequently. She continuously had had eczema on her hands until she quit her job because of marriage at age 26. She returned to her profession at age 29 but developed the same symptoms and quit her job after three months. She had believed that she was allergic to gloves, so she did not take a job that required wearing gloves. At age 30, she started to work again as a dental hygienist, wearing unpowdered latex gloves, but again developed hand eczema. She was offered nitrile rubber gloves, and the eczema on her fingertips was abated; however, it recurred again when she was busy. She suffered from insomnia due to itching for three weeks and consulted a dermatologist. She was treated with a topical corticosteroid and occasionally an oral corticosteroid, and her symptoms improved but were not cured completely. The constituents of the two kinds of two-component acrylic resin for temporary teeth she was using are shown in Table 3. She was patch tested with two kinds of gloves she actually used (nitrile and natural rubber gloves, as is), the two-component acrylic resins she used (10% pet. of powder and 1 and 2% pet. of liquid monomers of products A and B), 21 kinds of (meth)acrylates, 2 kinds of plastic additives, and 9 kinds of metals in a dental material series (Brial, Greven, Germany). Readings were performed 1 day after occlusion for 2 days (day 3) according to the ICDRG and the results are shown in Tables 2 and 3. Her severe hand eczema was diagnosed as ACD caused by methyl methacrylate (MMA), a main constituent of the liquid monomers of the two kinds of two-component acrylic resins she used, that penetrated through the nitrile rubber gloves she wore. In the 6 months since the patch tests and changing her nitrile rubber gloves immediately after they became contaminated with those acrylic monomers, she has been free from her symptoms.
| Products | Constituents | Conc. | Patch test results* (day 3) | |
|---|---|---|---|---|
| A | Liquid monomer | Methyl methacrylate | 98% | 2% pet. ++ |
| Tertiary aminen | 2% | 1% pet. ++ | ||
| Powder | Polymethyl ethyl methacrylate | 80% | 10% pet. − | |
| Polymethyl methacrylate | 20% | |||
| B | Liquid monomer | Methyl methacrylate | 100% | 2% pet. ++ |
| 1% pet. ++ | ||||
| Powder | Particulate substances | <99% | 10% pet. − | |
| Residual monomer | <1% | |||
| Benzoyl peroxide | <3% | |||
| Titanium dioxide | <1% | |||
| Mineral pigment 1 | <1% | |||
| Mineral pigment 2 | <1% | |||
| Azo pigment 1 | <1% | |||
| Azo pigment 2 | <1% | |||
Conc., Concentration; pet., petrolatum. *Readings were performed according to the ICDRG standard.
The most likely sensitizer for case 1 is ethyl methacrylate (EM), which comprised 90% of the monomer. Positive results were also found for the primer, 9% and 1% of which consisted glycerol dimethacrylate and pyromellitic dianhydride glycerol dimethacrylate adduct (PMGDM), respectively. These results could indicate concomitant sensitization or cross-reaction. Methacrylates often cross-react with each other1). The 5% of pet. of the remover was also positive both on day 3 and day 7, indicating that case 1 was probably co-sensitized with the remover, although the result for 1 % was negative. If the reaction had been irritation, it would have disappeared or diminished by day 7. Isopropyl alcohol and ethyl acetate can be rare sensitizers7). Ketones are irritants but not sensitizers7). ACD in a manicurist is not rare but in Japan only a few cases have been reported so far8, 9).
Case 1 was an amateur manicurist and applied nail art to her friends and herself. The author was provided with an opportunity to experience application of nail art by case 1. The parts of the procedures for application of nail art are shown in Fig. 2. During the procedures, the author observed that she did not mind if her fingers came in direct contact with the mixture of liquid monomer and powder. The author was afraid of developing ACD after the procedure because she had previously been sensitized with methacrylates4), but this did not happen. The major reason for why nothing happened was that the author was not exposed to uncured acrylic resin directly. The mixture of powder and liquid monomer should only be applied to the nail surface and extension templates. If the procedures were carefully done using the so-called non-touch method, the skin of both the manicurist and the customer would not be exposed. Occupational acrylic nail allergy is reported to be uncommon with only 10–15% of the reported cases occupationally related10). It is easy to see that a professional manicurist could be more careful with regard to use of the non-touch method in the procedures than case 1, who was an amateur manicurist as well as a user, and less exposed to nail art products. The numbness of the fingertips experienced by case 1 is known to occur with ACD from (meth)acrylates11).
Liquid monomer and powder are mixed and painted on nails and extension templates with a brush.
The causative chemical of case 2 was MMA, though she was wearing natural or nitrile rubber gloves. Dentistry workers often wear gloves when using dental acrylic materials, but many affected workers do not predict that acrylic monomer can penetrate the disposable gloves usually used, which are made by natural rubber, polyvinyl chloride, or nitrile rubber, and cause ACD, as in case 212). Such cases have been reported in Japan and the U.S.13, 14)
Besides acrylates, additives in dental plastics such as initiators, accelerators, catalysts, inhibitors, pigments, and various rubber chemicals cause ACD in dental personnel. Metals such as nickel, chromate, cobalt, gold, palladium, and mercury/amalgam can also cause contact sensitization6). In case 2, some of these allergens were shown to not have caused her symptoms by the patch tests (Table 2).
Methacrylates can often cross-react with each other but do not cross-react with acrylates as often1). Dental products, glues, and artificial nails usually contain methacrylates, and often contain epoxy acrylates, but they seldom acrylates1). Goon et al. reported that 2-hydroxyethyl methacrylate (2-HEMA) can be used to screen any sensitized dentistry worker15). For manicurists and their customers, 2-HEMA, ethyleneglycol dimethacrylate (EGDMA), and triethyleneglycol diacrylate (TREGDA) are recommended15). In Japan, patch testing with more than 22 preparations is not covered by medical insurance, so 2-HEMA is a useful tool for screening of dentistry workers13). Cyanoacrylate, which is an ingredient in one-component polymerization adhesives and is frequently used as a glue for pre-sculptured nail tips, as a bonding agent in daily life, and as a skin closure tool in medical treatment, does not cross-react with other (meth)acrylates16). Also, cyanoacrylate is reported to cause ACD in users of extension eyelashes, which have recently become popular17, 18). For screening of artificial nails and extension eyelashes, cyanoacrylate should be added.
The constituents of the nail art products used by case 1 were shown clearly on their containers, and a trader of the products was willing to inform us about the concentrations. The products were imported from the U.S. and were categorized as cosmetics, constituents of which have to be shown legally to customers. However, when the author made inquiries to a Japanese company about the constituents of their nail art products, the company was unwilling to report information about the ingredients. On the other hand, most of the Japanese manufacturers and traders of dental materials were ready to provide material safety data sheets19).
If the concentrations of constituents of (meth)acrylate products are not clear, the products should not be patch tested to avoid active sensitization, because it is impossible to dilute the products to an adequate concentration, that is, one that is high enough to elicit an allergic response but low enough not to cause active sensitization. The author experienced active sensitization when she was patch tested for irritation screening with preparations of UV-cured acrylic glue that a patient of hers was using4). It is recommended that the concentration of any methacrylate or acrylate in preparations of acrylic products not be more than 2% or 0.1%, respectively1).
The author, sensitized to methacrylates as described above, experienced ACD that lasted more than 2 weeks on the mucous membranes of her throat when she received a temporary two-component acrylic dental filling at a dental clinic. More careful gargling to remove excess monomer in her throat could have prevented this event. It had been reported that a person previously sensitized to nail art products can develop ACD from dental products20). (Meth)acrylates can trigger ACD when reexposure occurs in a different setting, which often occurs by cross-reaction with other acrylic compounds. Also, (meth)acrylates impurities can be contained in acrylic products and can cause ACD1).
Case 2 could free herself of her symptoms by changing her nitrile rubber gloves immediately after they became contaminated with a (meth)acrylate monomer. (Meth)acrylates easily penetrate through disposable gloves12). If a sensitized patient is told that disposable gloves cannot protect skin from acrylic products, he/she can frequently change contaminated gloves to prevent ACD. Double gloving with thin polyvinyl chloride or natural rubber gloves for a 15-min task with acrylics and sufficiently thick nitrile rubber gloves for 30 minutes of work are recommended1).
Airborne ACD can occur in a manicurist21, 22) and dental nurse23). Rhinitis with ACD in a manicurist24) and asthma and rhinoconjunctivitis in a dentist25) have been reported. To avoid these kinds of events, installation of a vacuum extractor and immediately closing bottles containing monomers are encouraged.
Acknowledgments: The author deeply thanks Dr. Sato K, Higashi-Kumamoto Hospital, Kumamoto, Japan, for her cooperation in treatment of the patients.
