Erik Zimerson

Contact allergy to (meth)acrylates in the dental series in southern Sweden: simultaneous positive patch test reaction patterns and possible screening allergens

Contact allergy to dental allergens is a well‐studied subject, more so among dental professionals than dental patients. 1632 subjects had been patch tested to either the dental patient series or dental personnel series at the department of Occupational and Environmental Dermatology, Malmö, Sweden. Positive patch tests to (meth)acrylate allergens were seen in 2.3% (30/1322) of the dental patients and 5.8% (18/310) of the dental personnel. The most common allergen for both groups was 2‐hydroxyethyl methacrylate (2‐HEMA), followed by ethyleneglycol dimethacrylate (EGDMA), triethyleneglycol dimethacrylate, and methyl methacrylate. 47 (29 dental patients and 18 dental personnel) out of these 48 had positive patch tests to 2‐HEMA. All 30 subjects who had a positive reaction to EGDMA had a simultaneous positive reaction to 2‐HEMA. One dental patient reacted only to 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloxypropoxy) phenyl]propane (bis‐GMA). From our data, screening for (meth)acrylate contact allergy with 2‐HEMA alone would have picked up 96.7% (29/30) of our (meth)acrylate‐allergic dental patients and 100% (18/18) of our (meth)acrylate‐allergic dental personnel. The addition of bis‐GMA in dental patients would increase the pick‐up rate to 100%.

Poor correlation between stated and found concentrations of diphenylmethane-4,4′-diisocyanate (4,4′-MDI) in petrolatum patch-test preparations

Diphenylmethane diisocyanate (MDI) is widely used in its polymeric form in the manufacturing of polyurethane products. Previous reports on MDI‐related contact allergy have shown a pattern, where patients seem to react to their own MDI‐based work material but not to commercial patch‐test preparations, which contain 4,4′‐MDI. Therefore, we performed chemical analyses of 14 commercial test preparations of 4,4′‐MDI obtained from 8 European and 4 American dermatology departments as well as 2 preparations from 2 major European suppliers of patch‐test allergens. A new method for monitoring 4,4′‐MDI in petrolatum preparations was developed and the determination of 4,4′‐MDI as the MDI‐dibutylamine derivative using liquid chromatography‐mass spectrometry was performed. None of the preparations obtained from the dermatology departments contained more than 12% of the concentration stated on the label. In most cases, 4,4′‐MDI content was only a few percentages or less of the concentration stated. 7 of the 14 preparations were analysed before the expiry date. Yet, only 1 of them, a preparation directly obtained from the supplier, came close to the concentration stated on the label. Thus, using these preparations, patients will be tested with a lower concentration than intended, leading to possible false‐negative reactions.

Contact Allergy to Phenol-Formaldehyde Resins

Adverse reaction to phenol‐formaldehyde resins include depigmentation, irritant dermatitis, chemical burns and allergic contact dermatitis. Allergic contact dermatitis from phenol‐formaldehyde resin has mainly been ascribed to resins based on paratertiary‐butyl phenol and formaldehyde, and such a resin is included in the ICDRG standard patch test series, based on phenol and formaldehyde, 26 patients were positive to at least 1 resin. The figures for positive reactions to paratertiary‐butyl phenol‐formaldehyde resin and the 2 other resins were 0.8%, 1.0% and 3.0% (440 tested subjects), respectively. Therefore, a battery of phenol‐formaldehyde resins should be used for screening purposes, since patch testing with the paratertiary‐butyl phenol‐formaldehyde resin is not sufficient to identify patients with contact allergy to phenol‐formaldehyde resins.

Shoe contact dermatitis from dimethyl fumarate: clinical manifestations, patch test results, chemical analysis, and source of exposure

Background: The methyl ester form of fumaric acid named dimethyl fumarate (DMF) is an effective mould‐growth inhibitor. Its irritating and sensitizing properties were demonstrated in animal models. Recently, DMF has been identified as responsible for furniture contact dermatitis in Europe.

How to optimize patch testing with diphenylmethane diisocyanate

We have previously shown that patch test preparations of polymeric diphenylmethane diisocyanate (PMDI) are more stable than preparations of diphenylmethane‐4,4’‐diisocyanate (4,4’‐MDI). This study was conducted to (i) investigate whether PMDIs yield as many positive reactions as 4,4’‐MDI, (ii) study concurrent reactions to 4,4’‐MDI and 4,4’‐diaminodiphenylmethane (4,4’‐MDA), and (iii) follow the course of positive reactions during 4 weeks. It was shown that PMDIs detect as many positive reactions as 4,4’‐MDI. Thus, they are better patch test agents being more stable than preparations of 4,4’‐MDI. We recommend that PMDIs with a monomer content of at least 35% is used in 2.0% petrolatum (pet.) (i.e. monomer patch test concentration approximately 0.7%). It was shown that reactions to 4,4’‐MDI and PMDIs appear late and we recommend readings on both day (D) 3/4 and D7. 4,4’‐MDA was shown to be a good marker for 4,4’‐MDI and patch testing with 4,4’‐MDA in 0.25% pet. can be used instead of PMDI. Concomitant reactions to 4,4’‐MDI and 4,4’‐MDA are probably not caused by conversion of 4,4’‐MDI into 4,4’‐MDA by reaction with water. Another explanation is a path of reactions leading to ureas and MDI conjugates with skin constituents, which are hydrolysed into 4,4’‐MDA. This complex process depends upon several factors and might explain why positive MDI reactions appear after D7.

Contact dermatitis from electrocardiograph‐monitoring electrodes: role of p‐tert‐butylphenol‐formaldehyde resin

Three cases of allergic contact dermatitis localized to the sites of electrocardiograph‐monitoring electrodes are reported. All patients had positive patch tests to both the gel and the adhesive part of the Red Dot® 2239 3M™ monitoring electrode used and to the p‐tert‐butylphenol‐formaldehyde resin (PTBP‐F‐R) of the standard series. Two patients had a history of possible exposition to the resin previously but there was no explanation for the third. No information about the presence of PTBP‐F‐R in the electrodes could be obtained from the manufacturers. Chemical analysis of samples of the electrode, using a gas chromatography‐mass spectrometry (GC‐MS) and high pressure liquid chromatography (HPLC) analytical system, demonstrated the presence of several PTBP‐F‐R derivatives in both the gel and the adhesive part.

Contact allergy to textile dyes in southern Sweden

Contact allergy to disperse dyes in textiles is documented in prevalence studies from southern Europe. To evaluate the prevalence of allergic patch test reactions to different textile dyes in southern Sweden, and to look at the sites of dermatitis in individuals hypersensitive to textile dyes, we retrospectively investigated 3325 consecutively patch‐tested patients. They had all been patch tested with the standard test series supplemented with a textile dye mix (TDM) consisting of 8 disperse dyes, i.e. Disperse (D) Blue 35, 106 and 124, D Yellow 3, D Orange 1 and 3 and D Red 1 and 17. All but 3 of the TDM‐positive patients were additionally tested with the separate dyes included in the mix. The frequency of contact allergy to TDM was 1.5%, which is comparable with studies from southern Europe. The most common dye allergen was D Orange 1. The high prevalence of allergic reactions to D Orange 1 was unexpected, whereas test reactions to D Blue 106 and 124 were lower than expected from other studies. Compared to all tested patients, the TDM‐positive patients more often had dermatitis on their arms, face, neck and axillary folds, and women also had a higher frequency of hand dermatitis.

Contact allergy to acrylates/methacrylates in the acrylate and nail acrylics series in southern Sweden: simultaneous positive patch test reaction patterns and possible screening allergens.

In a recent study we showed that all our dental personnel/patients were detected with 2‐hydroxyethyl methacrylate (2‐HEMA) and 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloxypropoxy)phenyl]propane (bis‐GMA). We studied 90 patients tested to the acrylate and nail acrylics series at our department over a 10 year period to see whether screening allergens could be found. Patch testing with an acrylate and nail acrylics series was performed. Among the 10 acrylate/methacrylate‐allergic occupational dermatitis patients tested to the acrylate series, the most common allergens were triethyleneglycol diacrylate (TREGDA, 8), diethyleneglycol diacrylate (5), and 1,4‐butanediol diacrylate (BUDA, 5). All 10 of these patients would have been picked up by a short screening series combining TREGDA, 2‐hydroxypropyl methacrylate (2‐HPMA), and BUDA or 1,6‐hexanediol diacrylate (HDDA). Among the 14 acrylate/methacrylate‐allergic nail patients, the most common allergens were ethylene glycol dimethacrylate (EGDMA, 11), 2‐HEMA, (9), and triethyleneglycol dimethacrylate (9). Screening for 3 allergens i.e. 2‐HEMA plus EGDMA plus TREGDA, would have detected all 14 nail patients. A short screening series combining 2‐HEMA, EGDMA, TREGDA, 2‐HPMA, bis‐GMA, and BUDA or HDDA would have picked up all our past study patients (dental, industrial, and nail) with suspected allergy to acrylate/methacrylate allergens.

Chemical investigations of disperse dyes in patch test preparations

Background:  Contact allergy to textile dyes is not uncommon. The allergy is detected by patch testing patients with commercial patch test preparations.

Photoallergic contact dermatitis from ketoprofen in southern Sweden.

The non‐steroidal anti‐inflammatory drug ketoprofen is widely used for topical treatment. In Sweden, ketoprofen has been available for topical application since 1995. Photoallergic contact dermatitis from ketoprofen‐containing topical preparations usually includes severe eczematous reactions. Ketoprofen is derived from propionic acid, and it is also a substituted benzophenone and therefore structurally similar to fenofibrate and sunscreen agents based on benzophenones. During the last 2 years, 35 patients have been refereed to our department with suspected photoallergic or allergic reactions after having used ketoprofen‐containing gels. Photopatch testing with the photopatch standard series, the ketoprofen‐containing gels and their ingredients, fenofibrate, benzophenone‐3, benzophenone‐10 and benzophenone‐4, was performed. Photoallergic reactions to ketoprofen were noted in 35 patients and a simultaneous contact allergy to ketoprofen in 2 patients. Simultaneous photoallergy to fentichlor, tetrachlorosalicylanilide and fenofibrate was registered in 74%, 40% and 73% of the patients, respectively.