This study included 1,752 patients considered to have occupational dermatoses. The most common diagnosis was contact dermatitis. The dermatitis was of an allergic type in three-quarters of men and in half of women. One-fifth of the women with irritant contact dermatitis had an atopic history. Contact dermatitis was localized on the hands in 94% of women and in 84% of men. The most common allergens in men were chromium, rubber and plastic, and in women nickel, rubber and chromium. Chromium allergy occurred in four-fifths of the men in the building, metal and tanning industries. In one-fifth of the women, nickel allergy developed in cleaning work. Rubber allergy developed in the rubber industry in one-fifth of the cases. Half of the women with contact dermatitis were engaged in either nursing or cleaning work. A follow-up 2-3 years after treatment of 555 patients with contact dermatitis was completed by means of questionnaires. The eczema was healed in one-quarter of the patients, one-half had periodic symptoms, and one-quarter had permanent symptoms. The prognosis was the same for those who changed their work or stopped working as it was for those who continued their eczema-inducing work.

The preservative Kathon CG is a commercial preparation, consisting of 2 active ingredients and other components. 28 patients with contact allergy to Kathon CG participated in a study in which patch testing was performed with serial dilutions, and with 5 chromatographically separated fractions. All reacted to fraction IV, and 2 patients also to fraction II. Mass spectrometry and nuclear magnetic resonance spectrometry identified fraction II and IV to be the active ingredients; 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one.

An outbreak of dermatitis occurred in an aircraft factory using epoxy resin composite material. Of 25 operatives, 14 gave positive patch test reactions to the composite material and/or diglycidylether of bisphenol A (DGEBA), tetraglycidyl-4,4'-methylene dianiline (TGMDA), and o-diglycidyl phthalate. This report seems to be the first to demonstrate contact allergy to the two last mentioned epoxy resins. The diglycidylether of bisphenol A used in routine test series picked up only 3 cases of 12 tested.

The phenoplastic in the ICDRG series is ptertiary butylphenol-formaldehyde. This is often used in glues and is then often not completely hardened to an insoluble network. However, there are many other phenols and aldehydes used in phenoplastics. Furthermore, the processing procedure provides different types. Phenols commonly used are phenol, cresols, xylenol, resorcinol, alkylphenols (p-tert. butyl-, diisoethyl-, cardanol, etc.), bisphenol A, pphenylphenol, etc. Aldehydes used are mainly formaldehyde and furfural.Different types can be manufactured: Resols are formed when formaldehyde is in excess to phenol in alkaline environment. These are, for example, used for impregnation of paper in laminates. Novolaks ("new shellak") are formed when phenol is in excess to formaldehyde in an acid environment. These are used for casting "bakelite" objects. First, methylol compounds are formed. Particularly in resols these can be stable for months. When the semi-cured resols or novolaks are hardened (polycondensated), the end product is a network, i.e. an insoluble resit. For polycondensation novolaks need the addition of formaldehyde or a formaldehyde releaser, e.g. hexamethylenetetramine, paraform. Resols can polycondensate by the presence of free methylol groups. Varnishes made of phenoplastics are made of alkyl-/arylphenols (p-tert. butyl-, p-octyl-, p-nonyl-, etc.) or are modified by the addition of colophony, fatty acids, terpenes. Then also glycerol, pentaery thritol or ethyl glycol are added to complete the esterification. Furthermore, there are alkyl-and epoxy-copolymers. Phenoxyplastics are made of epichlorhydrin and Bisphenol A but do not contain epoxide groups.Because of the great variety, it is necessary to patch test with the resins used by the patient. The reactions among our patients illustrate this. Of 5628 routine patch tested subjects, 94 (1.7 %) gave positive reaction; 49 subjects were additionally tested with a resol (5 % pet.) and a novolak (5 % pet.) because they had reacted to p.tert.-nutylphenolformaldehyde resin in the routine series or were known to have been in contact with noncondensated phenoplastics. Twenty-eight reacted to p-tert.-butylphenol-formaldehyde resin, 10 simultaneously to resol and three both to the resol and the novolak; 21 were negative to p-tert.-butylphenol-formaldehyde resin but all were positive to the resol. Ten of these reacted simultaneously to the novolak. Of the 31 resolpositive cases, 25 worked at the same plastic factory, where both resols and novolaks were used. All the novolak-positive subjects also worked there.In this material of 49 cases of contact allergy to phenol-formaldehyde resin, 21 cases would never have been traced if only routine patch testing had been performed.The simultaneous reactions among the three different resins can hardly be evaluated at this stage. Both for diagnostic and preventive purposes it is necessary to isolate and identify the sensitizers in different phenol-formaldehyde resins. This has been carried out in the case of p-tert.-butylph...

To diagnose allergic or irritant contact dermatitis, a clinically relevant contact allergy has to be demonstrated or ruled out, respectively. Although patch testing has been used for 100 years, it remains the method of choice for diagnosing contact allergy. A disadvantage of patch testing is that reading is subjective, based on inspection and palpation of the test area, implying that the assessment is subject to the reader's knowledge and experience. This study was carried out to investigate the accordance in reading patch test reactions between 5 dermatologists. 4 groups, each with 10 patients, participated. Within each group, all 10 were allergic to one and the same sensitizer; nickel, epoxy resin, ethylenediamine, or Kathon CG. The sensitizers were tested in serial dilutions and applied randomly to the back. The tests were read independently by the dermatologists in a blinded fashion. A protocol was used where the dermatologists had to note the presence of the morphological features erythema, infiltration, papules, vesicles, and bullae. In this way, it was possible to allocate the various readings into 4 classification systems, 3 European and one American, although the definition of the various classifications might differ slightly. Based on the readings and classifications, it was possible to calculate the degree of accordance within the 4 systems used. It was also possible to analyze the degree of accordance for the various morphological features. Total accordance for the 5 reading dermatologists for positive and negative test reactions was noted in 36% and 46%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)