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Background. Cross-reactions and co-sensitizations are of great importance in understanding contact allergy and exposure sources.Objectives. To investigate common cross-reactions and co-sensitizations in p-phenylenediamine (PPD)-sensitized and toluene-2,5-diamine (TDA)-sensitized individuals.Methods. Fromour patch test population, 8036 patients patch tested with the European baseline series were extracted. Readings had to be performed at least on day 3 according to ICDRG guidelines.Results. Two hundred and fifty-one patients were sensitized to PPD and/or TDA; 231 patients were sensitized to PPD, and 109 to TDA. Significant differences were observed regarding the strengths of patch test reactions to PPD and number of cross-reactions. For TDA, a difference was found between all reaction strengths, except between + and ++ strengths. PPD-sensitized individuals were more likely to be sensitized to carba mix, cobalt chloride, colophonium, p-tert-butyl phenolformaldehyde resin, paraben mix, and methylisothiazolinone. TDA-sensitized individuals were more often sensitized to carba mix.Conclusions. Cross-reactivity was commonly found among individuals sensitized to PPD or TDA, and was strongly related to the strength of the patch test reaction. Regarding co-sensitizations, a frequently appearing or common exposure source could not be determined. However, modification of the allergen by, for example, the skin microbiota may have caused the formation of molecules that are, for the human immune system, indistinguishable from PPD.

Background Allergic contact dermatitis is an increasingly recognized clinical problem in children. Objective The aim of our study was to evaluate contact sensitization in patients younger than 3 years of age with suspected contact dermatitis. Methods During a 6-year period (2002-2008), 321 children underwent routine patch testing with a screening pediatric standard series of 30 allergens. Results Two hundred children (62.3%; 102 girls and 98 boys aged 3-36 months [mean age 27 + 5.6 months]) developed at least one positive reaction. The most frequent reactions were to nickel sulfate (26.8%), followed by potassium dichromate (9%), cocamidopropylbetaine (7.2%), cobalt chloride (6.2%), neomycin sulfate (5%), and methylchloroisothiazolinone/methylisothiazolinone (4.4%). The prevalence of contact sensitization was similar in children with (61.3%) and without (63%) atopic dermatitis. Limitations The prevalence of contact sensitization in children younger than 3 years of age was not compared with the prevalence in older children. Conclusion A high prevalence of contact sensitization was found in preschool children, even younger than 3 years of age. Patch testing should be considered in this age group when persistent dermatitis does not respond to conventional treatment.

Background: A nation-wide Norwegian Patch Test Registry (NOLAR) was established in 2005 as a collaboration between six dermatology departments. International, multi-centre studies have documented great variability in the frequency of positive patch test reactions, considered as mainly due to heterogeneity of test populations. Objectives: To analyse the variability of positive test reactions by studying patch tests performed at the six collaborating departments, using standardized procedures. Materials and methods: Data from all patch tests (n = 2089) performed in 2007–2008 as registered in the NOLAR program. Differences between centres were analysed using Exact Pearson χ2 test. Results: Between the centres, positive test reactions (+, ++, or +++) varied significantly for 8 of the 26 allergens in the European Baseline Series. When considering strong reactions (++ or +++) only, the differences were statistically significant for six of these allergens, i.e. cobalt chloride, potassium dichromate, p-phenylenediamine, formaldehyde, paraben mix, and mercaptobenzothiazole. Conclusion: The results indicate regional differences in the prevalence of sensitization to certain allergens within the Norwegian population, although inter-observer differences cannot be ruled out as a factor.

Background : Footwear dermatitis represents a distinct and common group among all types of contact dermatitis cases seen in India. This ailment, however, often remains undiagnosed, misdiagnosed or empirically diagnosed without pinpointing the contributory allergens. Aims : This study was undertaken to detect the epidemio-allergological pattern of footwear dermatitis in India. Methods : A total number of 155 cases with footwear dermatitis were evaluated from July 2005 to June 2006, by detailed history and clinical examination. They were patch tested using Indian Standard Battery (ISB) approved by the Contact and Occupational Dermatoses Forum of India (CODFI) with pre- and post patch-test counseling. Results : The proportion of footwear dermatitis was 24.22% (n=155) among a total of 640 patients patch tested during that period. Females [61.93% (n=96)] were commonly affected than males [38.06% (n=59)]. The ages ranged from 8 to 75 years. The age group that predominantly involved was the fifth decade [24.52% (n=38)]. Occupationwise housewives were most commonly involved [47.48 (n=66)]. Contributory allergens in order of frequency were: potassium dichromate, 45.8% (n=71); cobalt chloride, 38.06% (n=59); paraphenylenediamine, 32.25% (n=50); epoxy resin, 20% (n=31); black rubber mix, 20% (n=31); nickel sulfate, 14.83% (n=23); mercaptobenzothiazole, 12.9% (n=20); colophony, 11.6% (n=18); thiuram mix, 10.32 % (n=16); p-tert-butyl-formaldehyde resin, 9.67% (n=15); and formaldehyde, 4.5% (n=7). Among the different categories of footwear allergens, the highest positivity was shown by leather and leather-related chemicals in 61.9% cases (n=96). Conclusion : Footwear dermatitis, a common dermatosis, is mostly caused by leather processing chemicals, metal buckles, black dyes of shoes and socks, adhesives, plastic, rubber shoes and polishing agents in order of frequency.

The reproducibility of patch tests is an important determinant of the clinical value of this diagnostic procedure. The aim of the present study was to delineate comparatively the efficiency and reproducibility of identical test reagents from 2 different commercial sources. Purchased in duplicate from brial and Boots-Hermal, 30 allergens from the European standard and an extension series were simultaneously applied to Finn Chambers and affixed next to each other. Out of 2070 paired patch tests in 71 patients, 97.2% presented with concordant-negative results. 60 patch tests were classified as allergic with 95% concordant-positive results. From these paired positive patches, a subgroup of 13 (22.8%) corresponding allergens presented with minor differences in the visible strength of the allergic reaction. Generated by cobalt chloride, formaldehyde and 2-bromo-2-nitropropane-1,3-diol in 1 patient each, discordant results, i.e. 1 positive and 1 negative test in parallel, were found in only 5%. Taken together, we were able to demonstrate that patch test preparations from 2 different companies exhibited a high level of reproducibility. This standardized quality of test reagents from different suppliers provides useful information on several aspects of everyday practice.

Background: Patch testing with additional series (AS) of allergens may be a useful tool in diagnosing allergic contact dermatitis (ACD). Objective: Aim of the study was to verify the usefulness, to check the reliability in clinical practice and to evaluate the economic costs of AS previously built up. Methods: A total of 281 patients with suspicious ACD underwent patch test with the standard series (SS) and with one or more AS (51 among 71 built up). Results: A total of 170 patients (60.5%) showed positive reactions to SS; 116 (41.3%) to AS. Among 582 nonstandard allergens used, 113 (19.4%) elicited 1 or more positive reactions: out of 10,916 patch tests carried out, 260 (2.4%) positive reactions were observed. The correlation between SS and AS indicated that 8.2% patients resulted SS[minus ]/AS+, 27.7% SS+/AS[minus ], 32.7% SS+/AS+, 31.3% SS[minus ]/AS[minus ]. The most frequently used AS showed the following percentages of patients with 1 or more positive reactions: clothes 41.4%, building industry 51.8%, hairdressers 77.3%, textile industry 42.1%, shoes 36.8%. Positive reactions to the most frequently used nonstandard allergens resulted: propylene glycol 0.4%, cobalt chloride 12.6%, phenylmercuric nitrate 2.2%, p -aminophenol 4.5%. The approximate economic cost of patch testing with AS has been evaluated in 1.3 per single patch test. Conclusion: The cost of patch testing AS is not irrelevant, but it can be compensated by the advantages deriving from the increase of data concerning ACD etiology. A reduction in the number of allergens included in single AS should be performed. Cobalt chloride, taking into account the high percentage of positive reactions observed and its presence in a large number of AS, could be (re)introduced in the standard series.

Background: Metal allergies can be clinical problem, especially in atopic individuals. This study is unique and contributes with new knowledge in everyday life skin care of irritant and atopic dermatitis patients. Objectives: The aim of the study was to determine the frequency of positive patch test reactions to metal contact allergens (potassium dichromate, cobalt chloride, nickel sulphate, white mercury precipitate) in patients diagnosed with allergic contact dermatitis, irritant contact dermatitis, and atopic dermatitis. Patients and Methods: Between 2007 and 2011, patch testing was performed in 2185 patients according to International Contact Dermatitis Research Group technique. Results: Study results showed statistically significant differences in patch test responses to 2 allergens, nickel sulphate (χ2 = 24.22; p < 0.001) and cobalt chloride (χ2 = 22.72; p < 0.001). Nickel sulphate was the most common allergen in allergic contact dermatitis and atopic dermatitis, while for irritant contact dermatitis the most common allergen was cobalt chloride. Among the 4 tested metal allergens the most common and relevant was nickel sulphate (χ2 = 17.25; p < 0.004), found in almost all examinees. Conclusion: The increased awareness of allergens and their potential sources may help to limit the use of these chemicals in consumer product manufacturing.

The aim was to mimic the repeated open application test (ROAT) procedure, well established in humans, in an animal model. Guinea pigs were induced with cobalt chloride (CoCl2). They were then challenged by repeated open application (4 sites/animal) of various concentrations of the allergen in 10% DMSO 1 x a day for 7 days, to study dose dependency, morphology of test reactions and time course. The reactivity at the test sites to repeated open application was dose- and time-dependent. There was good agreement between the results of the treatments with CoCl2 and the post-treatment patch test results. Among 26 of the 29 animals, such agreement was found when 10% DMSO was used as vehicle. However, some reactivity was also observed in pretests at sites exposed to petrolatum. We suspect that this may be due to contamination and/or irritancy of the vehicle.

Computer data on 4721 consecutive patients patch tested with an extended standard series were analysed for the frequency of allergic reactions to each substance. Particular Attention was given to the negative first reading at day 2 (D2) which later became positive at day 4 (D4). A total of 4210 allergic reactions were recorded. 993 of which were negative on D2(24%). The most frequent positive reactions were to nickel sulphate (18%), fragrance-mix (8%), colophony (6%), neomycin (6%), cobalt chloride (6%), thiuram-mix (4%) and potassium dichromate (3%). The frequency of negative D2, positive D4 readings was sizeable for all but one substance, primin, with a range of 14% for fragrance-mix to 64% for neomycin. All of 21 positive reactions to primin, with a range of 14% for fragrance-mix to 64% for neomycin. All of 21 positive reactions to primin were recorded on D2. In our opinion, it is unjustified to perform D2-only patch test readings.

Piercing the earlobes has increased in popularity among males in recent years. This habit would be expected to increase the incidence of nickel and cobalt sensitization. Patch testing with nickel sulfate and cobalt chloride was performed in 520 young Swedish men doing compulsory military service. The overall frequency of nickel/cobalt positive tests was 4.2%. The prevalence of nickel/cobalt positive tests was significantly higher (p0.05) in 152 men with pierced earlobes (7.9%) than in those 368 with unpierced earlobes (2.7%). A history of hand eczema (7/152 = 4.6%) or other types of eczema (22/152 = 14.5%) in individuals with pierced earlobes was no more common than in those with unpierced earlobes: 24/368 = 6.5% and 51/386 = 13.9%, respectively (n.s.). Hand eczema was no more common in sensitized (1/22 = 4.5%) than in nonsensitized individuals (32/498 = 6.4%) (n.s.).

458 consecutive patients were patch tested with a metallic cobalt disc as a supplement to the standard series. 23 patients had a positive reaction to CoCl2 1% pet. Of these, 19 were tested with the cobalt disc. 11 had a positive reaction and 5 a questionable reaction. There were no positive reactions to the cobalt disc in patients with a negative patch test to CoCl2 1% pet. Patch testing with CoCl2 1% pet. diagnoses all patients with allergy to metallic cobalt, but the test method is limited by a high number of irritant and questionable reactions.

We report a case of occupational allergic contact dermatitis from rhoidium sulphate and cobalt Chloride in a 29-year-old woman working in a goldsmith's workshop. the relevance and source of sensitization to these metals in our patient is described, and the literature on the subject reviewed.

79 male pupils of a metal industry school were investigated, none of whom had yet been occupationally exposed to metals or to cutting oils. In 1 or 2 years, depending on their grade and age, they would all be employees in the metal industry. Each was patch tested with nickel sulfate 5% pet, cobalt chloride 1% pet., and potassium dichromate 0.5% pet., and 28 had a positive reaction to 1 or more of the metals tested. This finding indicates the necessity not only fur pre-employement patch testing in industries where contact dermatitis is likely to occur, but that patch testing should be done even earlier in school children, before they decide to enter certain occupations.

4 patients with chronic photocontact dermatitis were sensitive to cobalt salts. They presented as cases of contact dermatitis from cement or pig fodder with persistent lesions on exposed areas. Only 2 of them had standard patch test positive reactions to chromate and cobalt, but all showed positive photo-patch tests to cobalt. Photo-oxidation tests proved that cobalt salts are photosensitizing. Exposure to cobalt salts was responsible for the patients' chronic actinic dermatitis.

4 strips of 5 Epiquick patch tests (19 allergens plus 1 control) were applied symmetrically in duplicate on the left and right sides of the upper back in 100 consecutive patients. 70 positive allergic patch test reactions were recorded on the left side and 67 on the right side. 67 positive reactions were concordant on both sides (64 with the same score of intensity and 3 with a different score). 3 positive reactions (in 2 patients) on the left side were negative on the right side (1 TMTD, 1 cobalt chloride and 1 wool alcohols). At rechallenge 6 weeks later, they were positive. No explanation could be found for negative results at the first challenge on one side and not on the other. The rate of non-reproducible positive results to the overall number of positive reactions was 4.2%. The good reproducibility rate (95.8%) provides useful information for further comparative studies.

The patch test results from 1,000 patients tested with the ICDRG standard series are analyzed for positive reactions to potassium dichromate, nickel sulphate, and cobalt chloride. Nickel appears to be the most common sensitizer, especially among women, although false-negative reactions may occur if it is tested with a 2.5% concentration in yellow petrolatum. Chromate dermatitis is generally of occupational origin among men. It is also quite common among Belgian women, probably because of the widespread use of Javel® (liquid bleach), containing sodium dichromate as a colouring and stabilizing agent. Positive patch test reactions to cobalt are generally accompanied by allergic reactions to nickel or chromate. Its role as a primary allergen, however, must never be overlooked. The relationship between these metals and hand and foot eczema is evaluated. The results of a follow-up questionnaire are given. More than 70% of the patients allergic to chromates or nickel continued to suffer from contact eczema after the diagnosis had been made and therapeutic measures taken.

Sixty-sis patients who had to undergo total hip replacement by means of a metal-to-plastic Stanmore prosthesis, were patch-tested prior to and 6 to 12 months after surgery with the standard ICDRG allergens series and with acrylic monomer 5 % in acetone. In 62 patients the history of metal allergy as well as the patch tests to all tested allergens were negative. One patient with a history of metal allergy reacted negatively before surgery; about 6 months after surgery the patch test to nickel sulphate was positive (2 plus). Three other patients developed positive patch test reactions after surgery: two reacted positively to nickel sulphate (2 plus) and one to cobalt chloride (2 plus). In none of the 66 patients have local side effects of the prostheses been found to date.