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German Contact Dermatitis Research Group (german + contact_dermatitis_research_group)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

FS04.5 Iodopropynylbutyl carbamate (IPBC) 0.2% is suggested for patch testing of patients with eczema possibly related to preservatives

CONTACT DERMATITIS, Issue 3 2004
Jochen Brasch
Iodopropynylbutyl carbamate (IPBC)is a preservative that has been increasingly used for skin care products and cosmetics within the last years and the first cases of contact sensitization have meanwhile been reported. Therefore, a surveillance for IPBC contact allergy is now necessary. Our study was aimed to find out a suitable test concentration of IPBC for this purpose. The data 8106 patients tested by 23 centres of the German Contact Dermatitis Research Group (DKG) and the Information Network of Departments of Dermatology (IVDK)in the time from May 2001 to July 2003 with IPBC in concentrations of 0.1%, 0.2%, 0.3%, and 0.5% were retrospectively evaluated. Criteria considered to determine the optimal test concentration of IPBC were the reaction index, the positivity ratio, the rate of crescendo reactions, and the relation of IPBC-reactions with MOAHLFA-indices, with irritant reactions to sodium lauryl sulfate, and with positive reactions to the most common standard contact allergens and 4 other preservatives. For statistical evaluations the exact McNemar test was applied and odds ratios were calculated according to the profile likelihood method, as derived from logistic regression analyses. The rate of positive reactions to IPBC increased from 0.5% with IPBC 0.1% to 1.7% with IPBC 0.5%, but there was a problem with sensitivity or specificity with both of these 2 concentrations. Therefore, we focused on IPBC 0.2%(0.8% positive reactions) and IPBC 0.3%(1.3% positive reactions) for further detailed analyses. An evaluation of the related parameters revealed that with IPBC 0.2% as compared to IPBC 0.3% a higher percentage of crescendo reactions, a higher reaction index, a lower number of doubtful reactions, a plausible association of positive reactions with reactions to other preservatives, nd no association with a pronounced skin irritability was found. In conclusion, we recommend to start with IPBC 0.2% for patch testing of all persons with contact dermatitis that may be related to preservatives. [source]

FC02.4 Meteorological factors and standard series patch test reactions

CONTACT DERMATITIS, Issue 3 2004
Janice Hegewald
The existence of seasonal patterns to patch test reactions has been described, but with conflicting causal interpretations. The potential seasonality of patch tests may be due to irritation, changes to skin barrier or changes to immunological functions caused by meteorological fluctuations. For example, increased skin irritability due to cold winter weather and low humidity may cause an increase in irritative/doubtful and weak positive (false positive) reactions. To investigate the extent of the association between weather and patch test results, consecutive patients (N = 73691) patch tested with the standard series of the German Contact Dermatitis Research Group (DKG) at German or Austrian IVDK (http://www.ivdk.de) centres were matched with weather data collected at a nearby (30 km radius) weather station. Temperature and absolute humidity (AH) on the day of patch test application and the two preceding days were averaged to represent the environment most likely to have influenced the skin condition at the time of testing. The results of 24 standard series substances were analyzed with multivariate logistic regression. Half of the standard series substances examined, including fragrance mix, nickel sulphate, and formaldehyde, exhibited evidence of a relationship with meteorological conditions. Fragrance mix and p-Phenylene diamine exhibited the strongest evidence of an association to weather, with the odds of the reactions in all three reaction categories (ir/?, +, ++/+++) increasing during winter conditions. Due to the association between weather and patch test reactivity, the potential effect of meteorological conditions should be considered in the interpretation of patch test reactions. [source]

Late reactions to the patch-test preparations para-phenylenediamine and epoxy resin: a prospective multicentre investigation of the German Contact Dermatitis Research Group

BRITISH JOURNAL OF DERMATOLOGY, Issue 4 2006
U. Hillen
Summary Background Late patch-test reactions, developing at day (D) 7 or later have been described for several allergens. Late reactions may reflect patch-test sensitization. Para-phenylenediamine (PPD) and epoxy resins (ER) are potent allergens and therefore may potentially induce patch-test sensitization. Up to now, there has been no prospective study on the frequency of late reactions in routine patch testing with these allergens. Objectives To assess the frequency of late reactions to PPD and ER. Patients/methods In 1748 patients PPD (PPD-base, 1% pet.) and ER [based on diglycidylether of bisphenol A (DGEBA, 1% pet.)], and in 812 patients, nickel sulphate (5% pet.) were removed from the test panel of the standard series and applied on the medial side of the upper arm. Patch-test occlusion time was 24 h in 588 (PPD and ER) and 241 patients (nickel sulphate), respectively, and 48 h in 1160 (PPD and ER) and 571 (nickel sulphate) patients, respectively. Patch tests were read on D1,3 and D2,3, respectively; additional late readings were performed on D7, D14 and D21 after patch-test application. Patients who were not able to return for all scheduled late readings were telephoned on D7, D14 or D21, and questioned about a reaction at the test sites. Patients were instructed to perform daily self-examination from D4 onwards and to return immediately to the clinic if a reaction at the upper arm became visible. Results Data of 1428 patients (ER and PPD) and 638 patients (nickel) were evaluable. In 25 patients (1·8%), patch tests became positive not before D7, among them 21 reactions to PPD (1·5%) and four reactions to ER (0·3%). In five of seven patients, repeated patch tests with PPD disclosed patch-test sensitization as the cause of the late reaction. All late reactions, except for one, occurred in patients in whom patch tests were applied for 48 h. No late reactions were seen with nickel sulphate. Conclusions PPD (1% pet.) elicited late reactions in 1·5% of routine patch tests, the majority of them probably being caused by patch-test sensitization. Therefore, the German Contact Dermatitis Research Group decided to remove PPD 1% pet. from the German standard series and to take efforts to optimize the patch-test conditions of PPD. One way to optimize PPD testing could be to reduce the exposure of PPD 1% to 24 h. Alternatively the patch-test concentration of PPD might be reduced. [source]