A case report of allergic reaction with acute facial swelling: a rare complication of dental acrylic resin

Introduction

Methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (2-HEMA), and ethylene glycol dimethacrylate (EGDMA) in dental resin materials are skin sensitizers.^1,2 These monomers may cause allergic contact dermatitis (ACD).

In recent years, the number of dental patients with resin allergies has increased.^3,4 According to previous reports, allergic reactions to dental resin are of the delayed type with the emergence of oral blisters and epithelial peeling.^5,6 In the present study, a case of resin allergy with rapid facial swelling after exposure to dental resin is described. To the best of our knowledge, no previously published studies have reported dental resin allergy with such acute symptoms.

Case report

A 55-year-old female Japanese patient attended a dental clinic in November 2021 for bridge treatment of the right upper lateral incisor to the first premolar. She had a history of periungual inflammation with gel nail use. A hard resin artificial tooth (ENDURA ANTERIO, Shofu Inc., Kyoto, Japan) was set as a temporary crown with polymethyl methacrylate (PMMA) self-adhesive resin cement. However, after 4 h, the patient noticed a painless swelling at the right upper lip mucosa. With the suspicion of acute inflammation, an antibiotic (300 mg cefcapene pivoxil hydrochloride, daily for 3 days) and anti-inflammatory analgesic (180 mg loxoprofen sodium, daily for 3 days) were administered orally, and the symptoms disappeared within 3 days. Nine days later, a temporary crown made of self-curing acrylic resin was temporarily fixed with carboxylate cement (Hy-Bond Temporary Cement, Shofu Inc.). However, 1 h after the treatment, she felt discomfort in the right facial cheek, and 2 h later, rapid swelling was observed from the right suborbital area to the cheek (Figure 1a).

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Figure 1.

Images of acute facial swelling after dental treatment in a 55-year-old female Japanese patient, showing: (a) facial appearance approximately 15 h after dental treatment; and (b) facial appearance approximately 19 h after the administration of corticosteroids and antihistamines.

The next morning, the patient was seen by an oral surgeon at the general hospital. She had clear consciousness and had no fever or pain at that time. Blood tests showed mildly elevated C-reactive protein (0.81 mg/dL) and platelet count (354 × 10³/μL), but her white blood cell count (7890 cells/μL) was within the normal range. Subcutaneous emphysema was also ruled out due to the absence of torsion or snow grip sounds at the swelling site. No systemic skin symptoms were found. Under the diagnosis of suspected allergy caused by dental material and facial oedema, the temporary crown was removed, she received oral corticosteroids (20 mg prednisolone, daily for 5 days) and antihistamines (60 mg fexofenadine, daily for 5 days), and the symptoms disappeared (Figure 1b).

The patient was referred to Hiroshima University Hospital, Hiroshima, Japan in February 2022 (1 month after the last swelling episode) for a detailed examination. At that time, no allergic symptoms occurred and no resin restorations were made. A prick test and a closed patch test were performed to search for allergens and diagnose the allergy type.

Dental treatment products, and their components, were applied as antigens for the tests. MMA (2%; Kanto Chemical Co., Inc., Tokyo, Japan), 2-HEMA (1%; Kanto Chemical Co., Inc.) EGDMA (2%; Tokyo Chemical Industry Co., LTD., Tokyo, Japan), ethyl methacrylate (2%; Kanto Chemical Co., Inc.), diurethane dimethacrylate (UDMA, 2%; Sigma-Aldrich, St Louis, MO, USA) were diluted in saline or petrolatum and used for the prick and patch tests, respectively. UDMA was not used for the prick test because it is insoluble in water.

In the prick test, self-adhesive resin cement primer, liquid and powder; self-curing acrylic resin liquid and powder; MMA; 2-HEMA; EGDMA; and EMA were assessed. Results were judged 15 min after the reagent was applied and all results were negative (Table 1).

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Table 1.

Results of prick tests in a 55-year-old female Japanese patient who had previously experienced facial swelling following dental treatment.

Prick test substance	Concentration/vehicle	15 min
Self-adhesive resin cement: primer	as is	–
Self-adhesive resin cement: powder	50%/PSS	–
Self-adhesive resin cement: liquid	50%/PSS	–
Self-curing acrylic resin: powder	50%/PSS	–
Self-curing acrylic resin: liquid	50%/PSS	–
MMA	2%/PSS	–
2-HEMA	1%/PSS	–
EGDMA	2%/PSS	–
Physiologic saline solution	as is	–
Histamine	10 mg/mL	7 × 6

2-HEMA, 2-hydroxyethyl dimethacrylate; EGDMA, ethylene glycol dimethacrylate; MMA, methyl methacrylate; PSS, physiologic saline solution.

In the patch test, self-adhesive resin cement (primer and polymerized), self-curing acrylic resin (liquid and polymerized), carboxylate cement liquid/powder admixture, MMA, 2-HEMA, EGDMA, EMA, and UDMA were examined and evaluated according to the International Contact Dermatitis Research Group criteria. ⁷ Positive results were observed for self-adhesive resin cement (primer and polymerized), self-curing acrylic resin (liquid and polymerized), 2-HEMA, and EGDMA (Table 2 and Figure 2).

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Table 2.

Results of closed patch tests in a 55-year-old female Japanese patient who had previously experienced facial swelling following dental treatment.

Patch test substance	Concentration/vehicle	Day 2	Day 3	Day 7	Result
Self-adhesive resin cement: primer	as is	++	++	++	++
Self-adhesive resin cement: polymerized	as is	++	++	++	++
Self-curing acrylic resin: liquid	1%/PSS	+	+	+	+
Self-curing acrylic resin: polymerized	as is	+++	+++	+++	+++
MMA	2%/Pet	–	–	–	–
2-HEMA	1%/Pet	++	++	++	++
EGDMA	2%/Pet	++	++	++	++
EMA	2%/Pet	–	–	–	–
UDMA	2%/Pet	–	–	–	–
Polycarboxylate cement: admixture	as is	–	–	–	–
Petroleum	as is	–	–	IR	IR

2-HEMA, 2-hydroxyethl dimethacrylate; EGDMA, ethylene glycol dimethacrylate; EMA, ethyl methacrylate; IR, irritant reactions; MMA, methyl methacrylate; Pet, petrolatum; PSS, physiologic saline solution; UDMA, urethane dimethacrylate.

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Figure 2.

Images from a 55-year-old female Japanese patient who had previously experienced facial swelling following dental treatment, showing positive patch test reactions to: (a) self-adhesive resin cement primer; (b) self-adhesive resin cement polymerized; (c) self-curing acrylic resin liquid; (d) self-curing acrylic resin polymerized; (e) 2-hydroxyethyl methacrylate; and (f) ethylene glycol dimethacrylate, at day 7 following application of the product.

Blood tests showed low non-specific immunoglobulin E (30.6 IU/mL), and complement C4 (30 mg/dL) and C1 esterase inhibitor (115.0%) were within the normal range.

The patient was diagnosed with ACD to 2-HEMA and EGDMA. Facial swelling, which occurred rapidly after dental treatment, was presumed to be a symptom of delayed-type allergic reaction. She subsequently avoided the use of resin materials, and the bridge was adhered with non-resin glass polyalkenoate cement (Ceramir Crown & Bridge QuickMix, Doxa Dental AB, Uppsala, Sweden). Since then, no similar symptoms with subsequent dental treatment without resin materials have occurred.

The study was conducted in accordance with CARE guidelines, ⁸ and written informed consent was obtained from the patient for treatment and for publication of the case and accompanying images. A copy of the patient consent form is available for review by the Editor of this journal. All patient data were de-identified. Ethics approval was not deemed necessary due to the case report study design.

Discussion

Acrylic resins are mainly composed of MMA and contain functional monomers, inorganic fillers, and polymerization initiators. After polymerization, the monomer MMA becomes the polymer PMMA and cures. However, unreacted MMA and other acrylic acid/methacrylic acid monomers remain as residual monomers after polymerization, and these monomers are considered to have harmful effects on the human body.^9,10 In particular, MMA, 2-HEMA, and EGDMA are reported to be strong sensitizers. ¹¹ These agents have been shown to cause delayed-type allergic symptoms, generally presenting as erythema, itching, blistering, and desquamation of the skin and mucous membranes half a day to several days after contact.^5,12 The patient in the present case had an acute-symptom-like allergic reaction and was treated according to the World Allergy Organization treatment guidelines for anaphylaxis.^13,14

In the present case, resin allergy was suspected because the symptoms appeared whenever the patient was exposed to resin materials, however, we hesitated to diagnose the case as delayed-type allergy because symptoms were accompanied by acute facial swelling. As the lesion was accompanied by acute facial swelling, it required differentiation from subcutaneous emphysema, acute inflammation, hereditary angioedema, and immediate-type allergic reaction, which would induce anaphylactic shock and dyspnoea because of pharyngeal oedema. Therefore, with the patient’s consent, a prick test and a blood test were performed for definitive diagnosis. Subcutaneous emphysema, acute inflammation, and hereditary angioedema were excluded due to the clinical manifestations and blood test results.^15–18 The prick test was negative for all allergens, which also excluded immediate-type allergy. The patch tests showed positive reactions to 2-HEMA and EGDMA, and these were present in the liquid and powder components of the self-curing acrylic resin and resin cement used. The patient had a strong allergic reaction to a liquid material of a self-curing acrylic resin, which caused extensive redness, swelling, and blistering on the forearm skin (Supplementary Figure 1). This skin reaction was diagnosed as a delayed allergic reaction to the reagent used during the prick test three days earlier. Based on the above, the prick test result was negative and the patch test result was positive. A previously published study reported that when allergens are absorbed through the oral mucosa, symptoms are more rapid and more severe than when they are absorbed through the skin. ³ In the present case, the causative agent was presumed to be absorbed from the oral mucosa, causing a strong allergic reaction and facial swelling similar to acute symptoms. The patient had no history of treatment with dental resin, however, 2-HEMA and EGDMA are ingredients of gel nail polish, and the patient had a history of periungual inflammation when using gel nail polish; thus, she was presumed to be sensitized by the gel nail polish resin. The patient subsequently avoided the use of resin materials, and the bridge was adhered with non-resin glass polyalkenoate cement.

For patients who develop dermatitis on contact with dental resin materials, it is recommended to identify allergenic resin monomers and other components by testing, and to use allergen-free materials. If detailed testing is difficult, resin-free metals, ceramics and luting agents should be used.

The first step in preventing resin allergy is to highlight and communicate the relevant information so that it becomes well known. Next, in order to prevent sensitization to resin, care should be taken to avoid direct contact with the resin monomer prior to curing and ventilate the room frequently. In addition, since resin monomers may penetrate gloves, it is recommended that hand washing be performed without fail even when gloves are worn.^6,19 To provide safe treatment, dental health care providers are required to always be considerate of allergies by inquiring about the frequency of contact with resin and any history of skin symptoms.

Here, a case of resin allergy with acute facial swelling after dental treatment is described. Delayed allergy of resin monomer is a dangerous condition that may cause acute soft tissue swelling and airway obstruction. This report informs and warns dentists of resin allergy.

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