PubMed Health⌕ Search

Biomedical subjects

Axel Schnuch

Publications and source records attributed to Axel Schnuch.

At least 19 recordsLinked to original sources
PubMed2006

Aniline--a 'historical' contact allergen? Current data from the IVDK and review of the literature.

OBJECTIVES: To assess whether aniline should be regarded as potential cause of contact allergy (CA). METHODS: Retrospective analysis of clinical data collected in a CA surveillance network (IVDK, www.ivdk.org) between 01/1992 and 06/2004 and review of pertinent literature. RESULTS: In the above period, 25 of the 1119 patients patch tested with aniline had positive (allergic) reactions; in 24 of these 25 patients, CA to p-phenylenediamine, p-aminoazobenzene or (in one case) another para-amino compound was additionally diagnosed. Exposure to aniline could not be ascertained in any of the cases, based on the available data. DISCUSSION: Previous clinical results, which have been summarized and tabulated, are partly difficult to evaluate, as they may lack detail, or test concentrations are higher than those currently recommended, possibly yielding false-positive reactions. In none of the studies had previous exposures to aniline been unequivocally identified. CONCLUSION: Based on clinical data it is unlikely that aniline is an independent sensitizer of current importance. However, it may elicit allergic reactions in subjects pre-sensitized to para-substituted amino compounds. In summary, supported by recent experimental evidence employing the local lymph node assay as a validated animal test system, it appears probable that aniline is a weak allergen.

Adult↗
PubMed2006

White petrolatum (Ph. Eur.) is virtually non-sensitizing. Analysis of IVDK data on 80 000 patients tested between 1992 and 2004 and short discussion of identification and designation of allergens.

UNLABELLED: Sporadic cases of contact allergy to white petrolatum, which is used as a vehicle in patch test preparations, have been reported. The quantitative relevance of the phenomenon remains yet to be elucidated. METHODS: Retrospective analysis of patch test data of the Information Network of Departments of Dermatology (IVDK, http://www.ivdk.org) between 1992 and 2004. RESULTS: Analysis of 79 365 patients patch tested with pure petrolatum yielded 27 '+' (0.03%) and 2 '+++' (0.003%) reactions. The majority of non-negative reactions (0.3%) was interpreted as doubtful (235) or mild irritant (32). The negative reaction index (RI) (-0.8), and the high positivity ratio (PR) (93%) especially a lack of concordance with patch test preparations containing > or=99% petrolatum indicate that many of the 'positive' (+) reactions have to be considered as irritant. There were 2 '+++' reactions. In 1 case, an 'angry back reaction' was confirmed. The other case is probably a reading or documentation error, as the majority of patch test reactions to preparations containing petrolatum remained negative in this case also. CONCLUSIONS: True allergic patch test reactions to white petrolatum are extremely rare and probably due to an individually increased susceptibility to allergens and/or irritants. This is in agreement with considering petrolatum as a non-sensitizer.

Allergens↗
PubMed2006

Allergic contact dermatitis due to beta-blockers in eye drops: a retrospective analysis of multicentre surveillance data 1993-2004.

Topically applied ophthalmic drugs are a potential cause of allergic contact dermatitis of the periorbital region. The objectives of this study were to assess the frequency and spectrum of contact allergy to topically applied beta-blocker containing eye drops. Data of the Information Network of Departments of Dermatology (IVDK) collected between 1993 and 2004 was analysed. Out of 112,430 patch-tested patients, 332 had been tested with their own topical anti-glaucoma eye drops containing different beta-blockers because of suspected allergic contact dermatitis. The frequency of positive test reactions was related to exposure intensity, as estimated by annual prescription rates in Germany. A total of 43/332 (12.95%) showed at least one positive patch test reaction. Positive reactions were observed to products containing timolol (n = 21), metipranolol (n = 13) and levobunolol (n = 11) without conceivable cross-reactivity. Whereas exposure to beta-blocker-containing eye drops remained stable over the years, as estimated by the prescription rates, a slight, non-significant increase in positive patch-reactions to these substances was noted. This is the first systematic analysis of a large set of data on patients' own beta-blocker topical medications, the results indicating that contact allergy should be considered as important, if rare, adverse event caused by this family of drugs.

Adrenergic beta-Antagonists↗
PubMed2005

Clinical update on contact allergy.

PURPOSE OF REVIEW: The aim of this article is to review recent findings in contact allergy, regarding clinical research. RECENT FINDINGS: The biocide methyldibromo glutaronitrile was identified to be an important sensitizer. Subsequently, it was banned from leave-on cosmetics in the European Union. Another group of important allergens that have been studied extensively included the fragrances oak moss absolute, isoeugenol, hydroxyisohexyl 3-cyclohexene carboxaldehyde and farnesol. A new fragrance mix II has been developed for standard testing, which includes the two latter compounds. Dose response studies have demonstrated broad individual variation of elicitation thresholds, dependent on the allergen concentration during induction, and other factors. Some unsuspected routes of exposure to allergens include oral, inhalational, connubial or airborne contact. Experimental studies provide a classification of newly introduced chemicals; increasingly, the local lymph node assay is supplementing and potentially replacing the guinea pig maximization test. Recent advances in occupational contact allergy include, for example, some attempts to improve diagnostics for epoxy resin and other plastic, glue, and cutting fluid components. SUMMARY: Constant awareness for new allergens, confirmed by critical evaluation, standardization of patch test materials, and the identification of temporal patterns and subgroups at risk will improve both the diagnosis and prevention of allergic contact dermatitis.

Allergens↗
PubMed2005

Patch testing with p-toluene diamine preparations of different ages.

Analyses of the stability of 1% p-toluene diamine (PTD) in petrolatum used for patch testing showed a rapid decline of the PTD concentration down to 0.1%, possibly due to the generation of dye complexes. To study whether the diagnostic quality of this test preparation is compromised by the chemical reactions taken place, a multicentre study was conducted by the German Contact Dermatitis Research Group (DKG), comparing patch test results in 177 patients with simultaneously tested PTD preparations of different ages. During the 10-month course of this study, the age of the batches ranged from 2 to 11 months for batch A, from 7 to 16 months for batch B and from 11 to 20 months for batch C. There were no statistically significant differences between reactions to batches A and B, A and C, and B and C. Agreement of patch test reactions to the 3 batches was very good and comparable to the general reproducibility of patch test with standard allergens. The chemical reactions mentioned above apparently do not affect the diagnostic quality of PTD patch test preparations because the true allergen probably is not PTD itself, but one or more of the reaction products.

Dermatitis, Contact↗
PubMed2005

Patch testing with patients' own cosmetics and toiletries--results of the IVDK*, 1998-2002.

Patch test results with products brought in by the patients collected by the members of the Information Network of Departments of Dermatology (IVDK) between 1998 and 2002 were analysed. 5911 patients were patch tested with their own cosmetics and toiletries during this period. The 34 082 single test preparations applied to these 5911 patients were manually assigned to 1 of 26 categories, based on the EU Classification Annex I to 76/768/EEC, which had been further refined. The leave-on product category most commonly tested was 'creams, emulsions, lotions, gels and oils for the skin' (n = 3621 tested, n = 312 positive). The rinse-off product type most commonly tested was 'bath and shower preparations' (n = 1333 tested, n = 71 positive). In one-third of patients tested positive to these products, no other positive test result was observed. In the remainder, positive reactions to the fragrance mix, Myroxylon pereirae resin, methyldibromo glutaronitrile, (chloro-)methylisothiazolinone, 2-bromo-2-nitropropane-1,3-diole and further ingredients of cosmetics and toiletries were more common than in product-negative patients. However, in view of the potential for false-positive reactions mainly to rinse-off products, the results must be interpreted with caution. In conclusion, testing of patients' own products can be regarded as efficient and safe, if in accordance with current recommendations.

Adult↗
PubMed2005

Skin-sensitizing and irritant properties of propylene glycol.

In the several publications reviewed in this article, propylene glycol (PG; 1,2-propylene glycol) is described as a very weak contact sensitizer, if at all. However, particular exposures to PG-containing products might be associated with an elevated risk of sensitization. To identify such exposures, we analysed patch test data of 45 138 patients who have been tested with 20% PG in water between 1992 and 2002. Out of these, 1044 patients (2.3%) tested positively, 1083 showed a doubtful, follicular or erythematous reaction (2.4%) and 271 explicit irritant reactions (0.6%). This profile of patch test reactions is indicative of a slightly irritant preparation, and thus, many of the 'weak positive' reactions must probably be interpreted as false positive. No private or occupational exposures associated with an increased risk of PG sensitization were identified, except for lower leg dermatitis. Therefore, according to our patch test data, PG seems to exhibit very low sensitization potential, and the risk for sensitization to PG on uncompromised skin seems to be very low.

Adult↗
PubMed2004

Contact sensitizations in metalworkers with occupational dermatitis exposed to water-based metalworking fluids: results of the research project "FaSt".

BACKGROUND: The composition of water-based metalworking fluids (wb MWF) is complex, and various admixtures may be added before or during usage. Wb MWF may cause irritant as well as allergic contact dermatitis. While several current case reports point towards allergens particularly related to wb MWF, systematic studies have not been performed for several years. From 1999 to 2001, a study on contact allergies among patients with occupational dermatitis (OD) called "Fruhzeitige Erkennung allergener Stoffe bei beruflicher und nicht-beruflicher Exposition" (German acronym: FaSt) was conducted by the Information Network of Departments of Dermatology (IVDK), funded by the employers' liability insurances in Germany (HVBG). OBJECTIVE: The objective of FaSt was to detect sensitization patterns related to particular occupational exposures. METHODS: Anamnestic and clinical data were gathered using a standardised questionnaire. Patch test results were recorded by computer within the IVDK routine procedure. In addition to descriptive statistical analyses, logistic regression analysis was performed to control the effect of potential confounders. RESULTS: Among the 1842 OD patients in the FaSt study, there were 160 metalworkers exposed to wb MWF, whose data is presented in this paper. A specific allergen pattern of these patients can be described: most frequently, sensitizations to monoethanolamine (MEA), colophony/abietic acid, and fragrance mix were observed. Additionally, cobalt, formaldehyde, formaldehyde releasers and other biocides are important allergens in these patients. CONCLUSIONS: Preventive measures and aimed in-depth research may be based on these results. The special MWF test series have to be kept up to date based on exposure information from the MWF industry and on continuous surveillance of the target group.

Adult↗
PubMed2004

The prevalence of contact allergy differed between population-based and clinic-based data.

OBJECTIVE: Epidemiologic evidence on contact allergy (CA) largely relies on clinical studies. However, the effects of the selection process until consultation as patient are largely unclear. STUDY DESIGN AND SETTING: Prevalences of contact allergy to important allergens estimated from the population-based nested case-control study "KORA Allergy Study" in Augsburg, Germany (a subsample from the third MONICA survey in 1997/1998, n=1141), were compared with proportions found in the Department of Dermatology of the Augsburg Municipal Hospital in patients of similar age patch tested between 1997 and 2000 (n=555). Prevalences were standardized for sex, age, and atopic dermatitis as potential confounders. RESULTS: Among the 25 substances tested, the fragrance mix (MONICA, estimated from the KORA Allergy Study: 11.4%, hospital: 12.9%) and nickel (MONICA: 9.9%, hospital: 12.9%) were the most common allergens. Larger differences between prevalences were noted particularly with ingredients of topicals used to treat varicose ulcers-a speciality of the Augsburg department, which is also reflected by comparing the department with the whole Information Network of (n =40) Departments of Dermatology (IVDK). CONCLUSION: This locally matched comparison illustrates the differential effect of selection until presentation in dermatological departments.

Adult↗
PubMed2004

Contact allergy in construction workers: results of a multifactorial analysis.

OBJECTIVES: To quantify the risk of contact allergy (CA) to important ubiquitous allergens associated with certain occupations, in particular the construction industry, and to identify possible time trends, controlling for potential confounding variables. METHODS: Bivariate as well as Poisson regression analysis of standardized anamnestic and patch test data comprising 82,561 patients assessed in the 33 German and Austrian contact dermatitis units of the Information Network of Departments of Dermatology (IVDK) between 1992 and 2000. RESULTS: CA to five of the 18 (groups of) allergens considered here were observed significantly more often in construction workers: dichromate, epoxy resin (BADGE), cobalt, thiurams and N-isopropyl-p-phenylenediamine (IPPD). Multifactorial analysis confirmed an increased risk of CA to these allergens in construction workers, compared with other occupations. A very strong association between cobalt and chromate allergy was found in construction workers (OR 39.1, 95% CI 21.1-79.6). CONCLUSIONS: Dichromate is still an prominent allergen in construction workers; as yet, there is only weak evidence of a decrease in Germany. Therefore, the addition of ferrous sulphate to cement, which has been a successful intervention in other countries, should be promoted further. Although CA to other important occupational allergens like thiurams, IPPD and epoxy resin or cobalt (very often associated with dichromate CA) is less frequent, prevention should address these allergens, too. The use of protective gloves with minimal intrinsic CA risk, e.g. due to thiurams in (synthetic) rubber or chromate in leather gloves, should be promoted.

Adult↗
PubMed2004

Contact allergy to fragrances: frequencies of sensitization from 1996 to 2002. Results of the IVDK*.

Increasing frequencies of sensitization to the fragrance mix (FM) have been acknowledged as a serious problem for many years. It is well known that the single compounds (SCs) of the FM contribute differently to the FM patch rest reactions. In this study, we were interested in the time trends of the FM, the SCs, Myroxylon pereirae resin (MP; balsam of Peru) and oil of turpentine (OT) as possible further indicators of perfume allergy and analysed the data collected by the Information Network of Departments of Dermatology multicentre project from 1996 to 2002. During the study period (1996-2002), the FM [8% petrolatum (pet.)], MP (25% pet.) and OT (1% pet.) were tested in 59,298, 59,334 and 59,478 patients, respectively. SCs were tested in a selected group of patients, ranging from n = 1083 to n = 1924 per year. A significant increase in the proportions of patients with positive reactions to FM, MP and OT between 1996 and 1998 is noted, and a significant decline from 1999 to 2002 (Cochrane Armitage trend test, P < 0.0001). The highest frequency of sensitization to the FM was 13.1% in 1999, and the lowest 7.8% in 2002. The number of concomitant reactions to OT, a surrogate marker for terpenes, in FM-positive patients was significantly increased between 1997 and 1999. Reactions to SCs in FM-positive patients were observed in 29.9% (oak moss absolute) to 5.9% (geraniol). There was no time trend in reactions to SCs, although the relative share was increased for isoeugenol, cinnamic aldehyde and geraniol in 1999. In summary, we report for the first time, a significant decline in sensitization to the FM, very probably due to a reduced exposure (less potent allergens used in fine fragrances, possibly less use of natural ingredient-based cosmetics and lowered use concentration of important fragrance allergens). The differences in ranking of SCs could stimulate (a) a redefinition of the FM and (b) a differentiated preventive and regulatory approach, with oak moss and isoeugenol being regulated strictly by prohibition, concentration limits further reconsidered and/or health warnings and clearly less noxious substances like geraniol treated less restrictively.

Bryophyta↗
PubMed2004

Isopropyl myristate recommended for aimed rather than routine patch testing.

Isopropyl myristate (IPM) is considered a very weak sensitizer. Patch test results with 20% IPM in petrolatum (pet.) in 8117 patients and 10% IPM in pet. in 4554 patients between January 1992 and December 2001 by the IVDK are presented. While irritant and questionable reactions were frequently observed, especially with 20% test concentration and 2-day patch test exposure, respectively, and a decrescendo pattern was common, morphologically positive reactions at day 3 were seen in only 16 patients, i.e. altogether 0.13%. In line with previous clinical and experimental evidence, our results indicate that IPM is an extremely weak sensitizer or possibly, in our material, not a sensitizer at all. IPM should thus not be tested routinely, but only in the case of suspected exposure as a possible source of allergic contact dermatitis, e.g. to cosmetics and perfumes, to avoid an unacceptable reduction of the positive predictive value of the test.

Adult↗
PubMed2004

Guidelines for the descriptive presentation and statistical analysis of contact allergy data.

The present guidelines aim to support clinical researchers in adequately presenting data on contact allergy, and to use statistical tests appropriate for their data. A description of the mode of selection of patients, and of their relevant demographic details, is an essential prerequisite for the correct interpretation of study results. Proportions and rates, if regarded as estimate of these parameters of a target populations, should normally be supplemented with confidence intervals to address precision. Concordance, i.e., agreement between two ratings in a dependent sample, must be quantified with a chance-corrected measure such as Cohen's kappa coefficient. If the diagnostic quality of an outcome is being assessed, standard measures like sensitivity and specificity, as well as the prevalence-dependent positive and negative predictive values should be calculated. Often, contact allergy to a certain substance depends on several factors. In this situation, depending on the research question, techniques like stratification, standardization or multifactorial analysis should be employed. With increasing complexity of statistical description and analysis, consulting with a biostatistician is often mandatory.

Confounding Factors, Epidemiologic↗
PubMed2004

Frequency of contact allergy in German children and adolescents patch tested between 1995 and 2002: results from the Information Network of Departments of Dermatology and the German Contact Dermatitis Research Group.

Allergic contact dermatitis (ACD) affects approximately 7% of the general population. To evaluate the frequency of ACD in children, we analysed patch test results collected by the Information Network of Departments of Dermatology between 1995 and 2002. Data of 285 children (6-12 year) and 2175 adolescent patients (13-18 year) were analysed to determine the frequency of sensitization to the 30 most common contact allergens, adjusting for age and sex. As control group, we defined adult patients (60-66 year, n = 7904). The top allergens in children were thimerosal, gentamicin sulphate, nickel-II-sulphate, ammoniated mercury, cobalt-II-chloride, fragrance mix, bufexamac, Compositae mix, propylene glycol and turpentine. The overall proportion of sensitized patients according to the patch test results was 52.6% in the children group compared to 49.7% in the adolescent group. These findings were similar in the adult group at 52.2%. The detailed analysis regarding sex, occupation, atopy, site of eczema and age showed distinct patterns in each group indicating age-specific exposures. Atopy-related diseases were more common in children compared to adults. On the basis of the data of this study, the relationship between atopy and the risk of development of ACD, at least in children, needs further investigation.

Adolescent↗