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Axel Schnuch

Publications and source records attributed to Axel Schnuch.

35 records · Page 2Linked to original sources
PubMed2004

Patch test results with the metalworking fluid series of the German Contact Dermatitis Research Group (DKG).

Based on the information of the interdisciplinary task force on allergy diagnostics in the metal branch, in 2001, the German Contact Dermatitis Research Group (DKG) compiled two metalworking fluid (MWF) test series with currently and previously used components, respectively. After 2 years of patch testing, we present results obtained with these series, based on data of the Information Network of Departments of Dermatology (IVDK). 251 metalworkers who were patch tested because of suspected MWF dermatitis in 2002 and 2003 were included in this retrospective data analysis. Of these, 206 were tested with the current MWF series and 155 with the historical MWF series. Among the current MWF allergens, monoethanolamine ranked 1st with 11.6% positive reactions. Diethanolamine (3.0%), triethanolamine (1.1%), and diglycolamine (1.9%) elicited positive reactions far less frequently. Allergic reactions to p-aminoazobenzene were frequently observed (6.0%), but the relevance of these reactions is still obscure. Positive reactions to biocides ranged from 4.5% for Bioban CS 1135 to 0.5% for iodopropynyl butylcarbamate and 2-phenoxyethanol. Concomitant reactions to formaldehyde, which caused positive reactions in 3.3%, and formaldehyde releasers occurred to varying extents without conclusive pattern. No positive reactions were seen to dibutyl phthalate, di-2-ethylhexyl phthalate, tricresyl phosphate, isopropyl myristate or benzotriazole. With the historical MWF test series, positive reactions to methyldibromo glutaronitrile (MDBGN) were observed most frequently. However, sensitization via allergen sources other than MWF seems likely, as MDBGN, during the study period, has been one of the most frequent preservative allergens in cosmetics and body care products. Other historical MWF allergens comprised morpholinyl mercaptobenzothiazole (3.3%), benzisothiazolinone (BIT; 2.0%) and Bioban P 1487(1.3%). BIT is currently used in MWF again, so it was shifted to the current MWF test series. As decreasing reaction frequencies to former MWF allergens that are no longer used can be expected, the historical series should be re-evaluated after some years. The test series with current MWF allergens has to be kept up-to-date based on information from industry and to be kept concise by eliminating test substances which never cause positive reactions.

Adolescent↗
PubMed2004

Contact allergy to farnesol in 2021 consecutively patch tested patients. Results of the IVDK.

Farnesol is one of the fragrances considered to be a significant contact allergen. Therefore, it was decided by the European Union to label products containing farnesol. Farnesol was tested [5% petrolatum (pet.)] together with the standard series between 1 January 2003 and 30 June 2003 in 2021 consecutive patients, 1243 females and 778 males. Of these, 22 [1.1%, 95% confidence interval (CI): 0.7-1.6%] had a positive reaction to farnesol. 147 (8.1%) of those 1825 tested to Myroxylon pereirae resin (balsam of Peru, 25% pet.) at the same time reacted positively, 143 (7.8%) of those 1823 tested to the fragrance mix (FM) (8% pet.) and 34 (1.9%) of 1831 tested to propolis (10% pet.). With regard to concomitant reactions in farnesol-positive patients, 5 of 22 reacted additionally to the FM [odds ratio (OR): 4.3; CI: 1.53-12.15] and 2 (of these 5) additionally to M. pereirae resin (OR: 1.27; CI: 0.29-5.54). The strongest association was seen to propolis (OR: 6.2; 95% CI: 1.4-27.7). Compared to those with negative reactions to farnesol, the group of patients allergic to farnesol was characterized by a higher proportion of young females and office workers, and the hand and the face were more often affected. In conclusion, farnesol is an important allergen. We recommend that farnesol should be included in a fragrance patch-test preparation and that its use should be regulated for consumer safety reasons. Furthermore, the extent of exposure to farnesol should be further studied.

Adult↗
PubMed2003

Association of allergic contact dermatitis with a promoter polymorphism in the IL16 gene.

BACKGROUND: There is evidence that IL-16, a cytokine that induces chemotactic responses in CD4(+) T cells, eosinophils, and dendritic cells, plays an important role during different types of cutaneous inflammatory responses, including allergic contact dermatitis (ACD) and atopic dermatitis (AD). OBJECTIVES: We sought to test for association between a promoter polymorphism in the IL16 gene (T to C transition at position -295) and ACD and AD, respectively. METHODS: IL16 -295 genotypes were determined in samples from 2 separate case-control studies with white individuals. The first study included healthy individuals (n = 310) and patients with ACD (n = 86). These patients were polysensitized as defined by a contact sensitization to para-substituted aryl compounds and at least one other structurally unrelated allergen. The second study comprised healthy subjects (n = 214) and patients with AD (n = 94). RESULTS: IL16 -295 genotypes were differently distributed among polysensitized and healthy control subjects (P =.0021). In particular, the IL16 -295*C/C genotype was overrepresented among polysensitized individuals (7.0% vs 1.0% in the control group; odds ratio, 7.68; 95% CI, 1.59-48.12). In contrast, there was no evidence for an association between the IL16 -295 polymorphism and AD. CONCLUSION: The IL16 -295 promoter polymorphism might influence susceptibility to contact allergy.

Allergens↗
PubMed2003

Occupational rubber glove allergy: results of the Information Network of Departments of Dermatology (IVDK), 1995-2001.

About 21% of the patients with occupational contact dermatitis registered in the Information Network of Departments of Dermatology (IVDK) in the years 1995-2001 were patch tested due to suspected rubber glove allergy. We analysed reaction frequencies to thiurams, dithiocarbamates, mercaptobenzothiazole (MBT) and its derivatives, thioureas, and 1,3-diphenylguanidine (1,3-DPG). Thiurams were by far the most frequent rubber allergens in these patients (16.2% positive reactions, age- and sex-standardized), and the reaction frequency showed a decline from 20.9% in 1997 to 12.8% in 2000. However, this trend was not statistically significant, and was followed by an increase to 16.5% in 2001. All other rubber allergens showed no time trend at all. Although, according to manufacturers' information, the use of dithiocarbamates and MBT derivatives in rubber glove production increased in recent years, these allergens elicited positive reactions in only about 3% of the patients tested, and showed no increasing trend. Thioureas and 1,3-DPG are not widely used in rubber glove production, and play only a minor role in rubber glove contact allergy. Most of the positive reactions to 1,3-DPG are probably false-positive, irritant reactions.

Adult↗
PubMed2003

Cytokine gene polymorphisms in allergic contact dermatitis.

Susceptibility to contact allergy may be influenced by genetically determined alterations in the production of pro- and anti-inflammatory cytokines. This report focuses on functional polymorphisms in the genes encoding for several cytokines involved in the pathogenesis of contact allergic responses, including tumour necrosis factor (TNF)-alpha (G-238 A, G-308 A), interleukin (IL)-1beta (C-511G, T+ 3953C), its natural antagonist, the IL-1 receptor antagonist (VNTR intron 2), and IL-6 (G-174C). Polymorphisms were investigated by PCR techniques among polysensitized individuals, defined as individuals with confirmed contact sensitization to para-substituted aryl compounds and at least one other structurally unrelated allergen (n = 86), and healthy control individuals without a history of eczema (n = 310). The distribution of TNFA-308 genotypes was significantly different in these groups (Padjusted= 0.0378). Compared with carriers of 2 wild-type alleles (TNFA-308*1/1 (*G/G)), carriers of the TNFA-308*1/2 (*G/A) and TNFA-308*2/2 (*A/A) genotypes tended to be more common among polysensitized individuals [OR = 1.54, 95% CI (0.92-2.55) and OR = 2.36 (0.84-6.51), respectively]. No significantly different distribution of genotypes was detected at any other polymorphic loci among control individuals without eczema and polysensitized subjects. These findings suggest a possible relationship between the TNFA-308 polymorphism and contact allergy. The results need to be confirmed in future studies.

Adult↗
PubMed2003

Patch testing with components of water-based metalworking fluids.

Water-based metalworking fluids (MWFs) may cause both irritant and allergic contact dermatitis. Several well-known MWF allergens are available for patch testing, but considering the wide variety of possible components used in MWF, our diagnostic arsenal covers only a small part of potential allergens. We therefore selected 13 frequently used MWF components that might be sensitizers and had not yet been tested routinely. In 5 centres, 233 dermatitis patients with present or past occupational exposure to MWF were patch tested with this and other panels. Only 7 patients showed positive reactions to the study panel. Allergic reactions to the emulsifier diglycolamine [syn. 2-(2-aminoethoxy) ethanol] were seen in 5 patients, and 1 patient each reacted positively to 2-amino-2-ethyl-1,3-propanediol (AEPD) and methyldiethanolamine (MDEA). Clinical relevance of the reactions to diglycolamine was unequivocally proven by its presence in the MWF from the patients' workplace in 3 cases. Diglycolamine seems to be an important MWF allergen, independently from monoethanolamine and diethanolamine. A test concentration of 1% petrolatum (pet.) appears to be appropriate. The importance of AEPD and MDEA as MWF allergens still remains to be established. The lack of positive test reactions to the other MWF components tested may be due to their low-sensitizing potential or too low a patch test concentration being used.

Adult↗
PubMed2003

Patch-test reaction patterns in patients with a predisposition to atopic dermatitis.

Patients with a predisposition to atopic dermatitis often need to be patch tested in order to detect possible contact sensitization. However, it is unknown whether immunologic or other peculiarities of atopic skin are related to altered patch-test reaction patterns. Our study was aimed at answering this question, because patch-test reaction patterns are of considerable practical importance in the reading and interpretation of patch tests. Therefore, we compared patterns of patch-test reactions in patients with a predisposition to atopic dermatitis and in control patients matched for sex, age, reason for testing and test centre. Patch-test results from 9 centres (2322 patients with a disposition to atopic dermatitis and 2126 matched controls) were evaluated retrospectively. All patients were tested with nickel sulfate, fragrance mix, potassium dichromate, lanolin alcohol, formaldehyde and mercury ammonium chloride. Patch tests applied for 1 day with readings on days 1, 2 and 3 were evaluated in order to cover the early phase of the reactions. Not unexpectedly, we found that, compared to the matched controls, patients with a predisposition to atopic dermatitis tended to have more doubtful and irritant reactions on day 1. As a new observation, it turned out that they had less reactions of crescendo pattern and more strong reactions on day 3. All these differences were slight/insignificant. A higher skin irritability in patients with a predisposition to atopic dermatitis is a likely explanation. In conclusion, standard methods for patch testing can be applied in patients with a predisposition to atopic dermatitis, but minor differences in reaction patterns should be considered.

Adult↗
PubMed2003

Contact allergy to ingredients of hair cosmetics in female hairdressers and clients--an 8-year analysis of IVDK data.

Not only hairdressers, but also their clients or home-users of hair cosmetic products may become sensitized to one of the product constituents. The present analysis addresses the question whether the pattern of sensitization is different in these 2 groups and includes female patients who consulted with the participating centres of the IVDK (http://www.ivdk.org) between 1995 and 2002, and in whom hair cosmetics have been considered as being causative of their contact dermatitis. Among these, 2 subgroups were identified: (i) patients, currently or previously working as hairdressers, diagnosed with occupational skin disease (H, n = 884) and (ii) patients who never worked as hairdressers, i.e. clients (C, n = 1217). Previous atopic eczema was twice as common among H, who were also much younger (median age 24 versus 46 in C). Analysis of sensitization frequencies and patterns showed the well-known decline of contact allergy to glyceryl monothioglycolate (GMTG) in H from 31.2% to 8.5%. Among the C, 1.7% were allergic to GMTG. Concerning p-phenylenediamine, a steady decline from 27.6% to 17.2% was observed in H, while no trend was found in C (12.6% and 16.6% in the first and the last 2-year period, respectively). Conversely, a very slight decline of p-toluenediamine sensitization was observed in H (from 29.5% to 24.8%), while at the same time a significant increase was noted in C (from 8.7% to 16.7%). A slighter increase was also noted with ammonium persulfate in C (3.1-6.8%), while the proportion of H sensitized remained largely constant at about 26%.

Adolescent↗
PubMed2003

Contact sensitization to N-(cyclohexylthio)phthalimide.

Previous reports revealed relative high sensitization rates to the rubber chemical N-(cyclohexylthio)phthalimide (CTP; CAS-No. 17796-82-6), but the relevance of positive reactions remained unknown. It was discussed whether the test concentration of 1% pet. needed to be changed. The German Contact Dermatitis Research Group (DKG) added CTP in 3 concentrations, i.e. 0.25% pet., 0.5% pet, 1% pet., to the rubber series. From June 1999 to December 2000, 1936 patients in 30 departments of dermatology were tested with CTP. Of the 56 patients with a positive test reaction (2.9%), 52 reacted to CTP 1% pet., 21 to CTP 0.5% pet., and 9 to CTP 0.25% pet. The reaction indices were about the same with all concentrations. 34 patients with a positive reaction to CTP 1% pet. did not react to the lower concentrations. The majority of these reactions are probably false-positive. With CTP 0.25% pet., however, the majority of true allergic reactions to CTP were missed. Analysis of population characteristics and concomitant sensitizations to other rubber chemicals led to the conclusion that a positive reaction to CTP 0.5% pet. was a good indicator of contact allergy to CTP. Thus, the DKG decided to continue patch testing with CTP 0.5% pet. in the rubber series. Manufacturers' information about the use of CTP seem to partly contradict the patients' characteristics seen in this study. So the relevance of positive CTP patch test reactions, and the causative exposures in patients with CTP allergy, still remain to be clarified.

Adult↗
PubMed2002

Patch tests with thiurams at 0.25% pet. and 1% pet. are of equal diagnostic value.

Thiuram mix is tested in the standard series at a test concentration of 1% pet. The single thiurams (DPTD, TMTD, TMTM, TETD), however, are usually tested at 0.25% pet. in Germany. In other countries, the individual components of thiuram mix are tested at 1% pet. The German Contact Dermatitis Research Group (DKG) compared both patch test concentrations in 530 patients in order to find out if (i) a significant number of positive patch tests are missed by testing at the lower concentration, (ii) problems with irritant test reactions occur by increasing the test concentration to 1%, and (iii) the sensitivity of the thiuram mix rises when the breakdown test is done with the higher concentration. Slightly more positive reactions were seen with the higher concentration, but this increase did not reach statistical significance. The reaction index, as a measure for the relation of positive to irritant and/or questionable reactions, remained unchanged for the individual thiurams. The sensitivity of the mix also did not change when the breakdown test was performed with 1% pet. instead of 0.25% pet. Thus, we conclude that both concentrations are of equal diagnostic value in patch testing.

Dermatitis, Allergic Contact↗
PubMed2002

Lyral has been included in the patch test standard series in Germany.

Lyral 5% pet. was tested in 3245 consecutive patch test patients in 20 departments of dermatology in order (i) to check the diagnostic quality of this patch test preparation, (ii) to examine concomitant reactions to Lyral and fragrance mix (FM), and (iii) to assess the frequency of contact allergy to Lyral in an unselected patch test population of German dermatological clinics. 62 patients reacted to Lyral, i.e. 1.9%. One third of the positive reactions were + + and + + +. The reaction index was 0.27. Thus, the test preparation can be regarded a good diagnostic tool. Lyral and fragrance mix (FM) were tested in parallel in 3185 patients. Of these, 300 (9.4%) reacted to FM, and 59 (1.9%) to Lyral. In 40 patients, positive reactions to both occurred, which is 13.3% of those reacting to FM, and 67.8% of those reacting to Lyral. So the concordance of positive test reactions to Lyral and FM was only slight. Based on these results, the German Contact Dermatitis Research Group (DKG) decided to add Lyral 5% pet. to the standard series.

Aldehydes↗
PubMed2002

Diagnostic screening for contact allergy to mercaptobenzothiazole derivatives.

BACKGROUND: A patch test with an allergen mix used as screening test should be highly sensitive so that allergic patients are not missed. A previous analysis based on patch test data from 1990 to 1993 has shown that the mercapto mix lacked sensitivity. Chemical analyses on the stability of the mix components led to a new composition of the mix in 1995. METHODS: The authors analyzed retrospectively patch test data from the Information Network of Departments of Dermatology to evaluate the sensitivity of the newly formulated mercapto mix and mercaptobenzothiazole (MBT) for detecting contact allergies to the 3 MBT derivatives contained in the present mix. RESULTS: The new mercapto mix had a sensitivity of only 0.60, whereas MBT had a significantly higher sensitivity of 0.69. However, even this means that more than 30% of the patients allergic to MBT derivatives are missed. The combination of MBT and mercapto mix had a sensitivity of 0.77 for detecting contact allergies to the MBT derivatives. CONCLUSION: The German Contact Dermatitis Research Group decided to test both mercapto mix and MBT within the standard series, and to apply the 3 single components of the mix in case of a positive reaction to the mix or MBT.

Allergens↗
PubMedDate not supplied

An attempt to improve diagnostics of contact allergy due to epoxy resin systems. First results of the multicentre study EPOX 2002.

Epoxy resin systems (ERSs) are a frequent cause of occupational allergic contact dermatitis. Sensitization occurs not only to the resins, but also to hardeners and reactive diluents. However, only a fraction of the ERS components currently in use are available for patch testing. With the multicentre study EPOX 2002, we attempted to improve diagnostics in this field by patch testing with components currently used in ERSs. During the first study period (October 2002 to July 2003), in addition to commercially available ERS patch test substances, 16 study substances (1 resin, 9 hardeners and 6 reactive diluents) were patch tested in 70 patients with suspected contact allergy due to ERSs and 22 patients with a prior positive patch test reaction to epoxy resin (ER) in the standard series. Most frequently, allergic reactions to ER based on diglycidyl ether of bisphenol A and F were observed (55.2% and 43.7%, respectively). Agreement between positive reactions to both resins, which can be explained by immunological cross-sensitization and/or coexposure, was substantial [Cohen's kappa 0.65 (95% CI: 0.49-0.80)]. Among the reactive diluents, 1,6-hexanediol diglycidyl ether (1,6-HDDGE) and 1,4-butanediol diglycidyl ether (1,4-BDDGE) were the most frequent allergens, with 19.5% and 18.4% positive reactions, respectively. Although agreement between positive reactions to 1,6-HDDGE and 1,4-BDDGE was even better than with the 2 resins, the sample size is considered too small to decide reliably whether 1,6-HDDGE alone could serve as a marker allergen for both. Allergic reactions to p-tert-butylphenyl glycidyl ether and to phenyl glycidyl ether (PGE) occurred in 11.5% of the patients tested, with only moderate agreement. All patients positive to cresyl glycidyl ether (6.8%) also reacted to PGE. Of the hardeners tested, m-xylylene diamine was the most frequent allergen (13.8%), followed by isophorone diamine (5.7%). No reactions were observed to several substances, the test concentration of which may have been too low and will be increased in the future.

Adolescent↗