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.