This study comprises 40 patients with skin disorders from current or previous occupational exposure to epoxy resin compounds (ERC) during 1984-1988. ERCs were the 3rd most common cause (32 of 264 cases: 12.1%) of currently relevant allergic contact dermatitis: 23 cases from epoxy resins based on the diglycidyl ether of bisphenol A (DGEBA-ERs), 5 from reactive diluents, 1 from amine hardeners (DETA), and 3 from epoxy acrylates. 2 cases (0.8%) of irritant contact dermatitis were due to ERCs. Methyl hexahydrophthalic anhydride (MHHPA, an epoxy hardener) caused 1 case of contact urticaria. Previously relevant occupational allergic contact dermatitis from DGEBA-ERs was detected in 5 cases. On patch testing, ERC allergens gave the following positive reactions: epoxy resin of the standard series in 35 cases (4.0% of 870 tested), epoxy reactive diluents in 10 (7.1% of 140), cycloaliphatic epoxy resins in 4 (11.1% of 36), epoxy acrylates in 4 (4.5% of 88), and amine compounds commonly used as epoxy hardeners in 17. Despite extensive patch test series, testing with patients' own ERCs remains important.

The rôle of contact allergies in oral mucosal diseases was studied. The subjects were 24 patients out of 479 tested, who had oral mucosal symptoms and positive patch test reactions in a dental series during 1987-1994 at the Department of Dermatology, Helsinki University Hospital. The clinical diagnoses were oral lichen planus (LPO, 13 patients), leukoplakia (2), glossodynia, i.e., 'burning mouth syndrome' (4), stomatitis (3) and recurrent angioedema (2). Only 1 patient had symptoms in relation to dental care. All but 2 patients had allergic reactions to mercury (Hg) (12 patients), gold sodium thiosulfate (Au) (13 patients) or both. A clinical connection between oral symptoms and contact allergy was seen in 10 patients. 9 patients (7 LPO, 2 leukoplakia) had Hg allergy. In these cases, the oral lesions disappeared after the amalgam fillings had been removed. 1 patient had recurrent stomatitis and perioral eczema after dental care and 2,2-bis(4-(2-hydroxy-3-methacryloxypropoxy)phenyl)propane (BIS-GMA) allergy. Her symptoms were caused by drilling of acrylic fillings. In addition, a connection between localized stomatitis and contact allergy was considered probable in 2 cases. 1 patient had stomatitis from contact with an orthodontic device and nickel allergy. The other had stomatitis from contact with a dental gold crown and gold allergy. No clinical connection was found between gold allergy and the oral symptoms of other patients.

It is known from experimental studies that antigenic potency and the concentration of antigen determine whether exposure to an antigen will result in sensitization. A single accidental exposure to concentrated antigen may therefore induce primary sensitization. The purpose of this report was to collect clinical cases in which a single exposure had resulted in contact dermatitis suspected to be allergic. Only patients without previous relevant skin symptoms were included. Patch testing was used to demonstrate sensitization. 6 patients developed occupational allergic contact dermatitis from accidental exposure. Patch testing revealed allergy to diglycidylether of bisphenol A epoxy resin, polyfunctional aziridine hardener, methyl acrylate, phenol-formaldehyde resin, and methylchloroisothiazolinone/methylisothiazolinone (Kathon LX), respectively. Furthermore, 2 patients developed allergic contact dermatitis from their first exposure to tear gas chemicals, namely omega-chloroacetophenone and ortho-chlorobenzylidene malonitrile. A single exposure can therefore induce both sensitization and subsequent allergic contact dermatitis without further exposure. The allergens described must be considered strong allergens. The skin should immediately be cleaned if an accidental splash with such an allergen has taken place.

No abstract

Para-tertiary-butylcatechol (PTBC) is a rare allergen which is used in the rubber, paint and petroleum industries. We present 9 patients who were sensitized to PTBC and examined at the Finnish Institute of Occupational Health (FIOH) between 1974 and 1995. 3 of the patients had been exposed to PTBC in their work. 2 of them also had allergic reactions to para-tertiary-butylphenol (PTBP)-formaldehyde resin and to PTBP. 5 of the patients became sensitized to PTBC from patch testing. PTBC was found to be one of the most common causes of active sensitization in our clinic. Accordingly, at the FIOH, the patch test concentration of PTBC was lowered to 0.25% and this lower concentration is recommended for general use.

No abstract

Patch testing with allergens in the dental screening series, including (meth)acrylates and mercury, needs to be performed to detect contact allergy to dental products.

Occupational diseases of dentists and dental nurses were compiled from the Finnish Register of Occupational Diseases. The cases were recorded during 3 3-year observation periods, namely 1982-1984, 1986-1988, and 1992-1994 (i.e., 9 observation years). The relative risk of developing occupational allergic contact dermatitis in different occupations was calculated from the statistics of the years 1986-1991, and was expressed as the age-standardized rate ratio (SRR). During the 9 observation years, the majority of registered occupational diseases of dentists and dental nurses were skin diseases (221/312; 70.8%), followed by occupational repetitive strain injuries (61/312; 19.6%) and occupational respiratory diseases (20/312; 6.4%). The incidence rate (IR) for allergic contact dermatoses/10,000 workers (contact urticaria included) increased from 26 (95% confidence interval (CI) 16-40) in 1982-1984 to 79 (95%, CI 64-97) in 1992-1994. The IR/10,000 of allergic contact dermatoses increased especially for dentists, from 5.4 (95% CI 0.7-19) in 1982 to 67 (95% CI 45-95) in 1992-1994. The increase of the IR/10,000 dental nurses was smaller: from 43 (95%, CI 26-66) in 1982-1984 to 87 (95% CI 67-111) in 1992-1994. There was no increase in the IR/10,000 cases of irritant dermatoses. The most common causes of allergic contact dermatitis were plastics, disinfectants and antimicrobials, rubber chemicals, and mercury/mercury salts. The most common causes of irritant contact dermatitis were detergents, wet and dirty work, plastic chemicals and antimicrobials. Currently, Finnish dentists have the highest risk and dental nurses have the 4th highest risk of any occupation for developing occupational allergic contact dermatitis: the risk was 6.4-fold (SRR 6.4) in dentists and 6.1-fold in dental nurses, as compared to the general working population. It is evident that safer acrylics and protective gloves, better product declarations and material safety data sheets, as well as more information about protective measures, including non-touch working techniques, are needed.