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Biomedical subjects

A Schnuch

Publications and source records attributed to A Schnuch.

At least 19 recordsLinked to original sources
PubMed2007

Contact allergy to topical drugs: prevalence in a clinical setting and estimation of frequency at the population level.

OBJECTIVES: To estimate the prevalence of contact allergy (CA) to a set of topical drugs patch tested in the research network IVDK (Information Network of Departments of Dermatology; www.ivdk.org) between 1995 and 2004, and to extrapolate these clinical data to the German population. METHODS: Clinical data comprised results of allergy patch tests with topical drugs in patients with suspected CA. Clinical epidemiology and drug utilization research (CE-DUR) methods were employed to grossly estimate the incidence of CA to these topical drugs during two 5-year periods (1995-1999 and 2000-2005) in the German general population. To estimate the number of persons eligible for patch testing (with the topical drugs) on a general population level, sales data of patch test material were obtained. By relating this denominator to the CA frequency observed in the IVDK, the incidence of CA to selected topical drugs in the German general population was crudely estimated. RESULTS: In general, topical aminoglycosides showed the highest CA frequencies and, except for gentamicin sulfate, frequencies of CA to all other allergens tested were lower in the 2nd period of analysis. According to the medium model, 1-year incidence rates ranged from 1 (hydrocortisone-17-butyrate) to 29 persons/100,000 (neomycin sulfate) in the general population (1995-1999). CONCLUSION: The CE-DUR approach yielded incidence estimates of CA to relevant topical drugs in the German general population, which, despite their limited precision in absolute terms, illustrate the relative frequency of this particular adverse effect. However, comparative risk assessment should preferably take exposure information into account.

Administration, Topical↗
PubMed2006

[The most frequent allergens in allergic contact dermatitis].

BACKGROUND AND OBJECTIVE: The prevalence of allergic contact dermatitis is high. Patch testing is the standard procedure to detect contact sensitivity. More than 3000 allergens are known, today. On the basis of the data of this study the top allergens are presented. PATIENTS AND METHODS: The retrospective analysis is based on the patch test results collected by the Information Network of Departments of Dermatology in 2004. Data of 9948 patients (6175 female und 3773 male) referred for the evaluation of suspected contact allergy were analysed to determine the frequency of sensitization to the 10 most common contact allergens. RESULTS: The top ten allergens were nickel sulphate (frequency of sensitization standardized for sex and age 17.2 %), fragrance mix (7.2 %), balsam of Peru (6.7 %), cobalt chloride (6.5 %), potassium dichromate (5.3 %), colophony (4.6 %), lanolin alcohol (4.3 %), p-phenylenediamine (4.2 %), ammoniated mercury (3.5 %) und methyldibromoglutaronitrile/phenoxyethanol (3.4 %) in 2004. CONCLUSIONS: Even after healing of the skin lesions of allergic contact dermatitis, it must be considered that sensitization persists indefinitely. Therefore, patients have to be informed exactly about their relevant contact allergens to ensure complete avoidance. To do so, physicians need a detailed knowledge of the most common contact allergens which are discussed in this paper.

Adult↗
PubMed2006

[Environment-related contact allergies].

Contact allergies are frequent diseases and often lead to social and economic consequences for the patients. The incidence of the clinically manifest allergic contact eczema is between 1.8 and 7 per 1,000 per year, according to the data of the Information Network of Departments of Dermatology (IVDK; http://www.ivdk.org). Contact allergies are frequently acquired at the workplace, but a sensitisation and subsequent manifest disease (elicitation) occurs even more often in the private sphere and then poses a special problem. Even if occupational exposure to the allergen is prevented, e. g. by giving up the job, a full remission is only achieved in about half of the cases due to the ubiquitous existence of the responsible allergens. Contact with substances that have a high sensitisation potential can be avoided to a great extent. Prevention can be achieved by personal protective measures, a decrease of the applied concentration of the allergen, or even restrictions concerning certain chemicals. The prerequisite for this is continuous monitoring of the frequency of sensitizations towards known allergens, as well as an understanding of the substances in use in the environment, including newly introduced chemicals, and the education of the public.

Dermatitis, Allergic Contact↗
PubMed2006

Strong allergic patch test reactions may indicate a general disposition for contact allergy.

BACKGROUND: Patch test patients have two or more positive reactions to unrelated allergens more often than to be expected by chance. This study evaluates synchronous patch test reactions to test the hypothesis that in such cases an allergen-independent disposition for contact sensitization may be involved. METHODS: Data of 87 834 patients tested with a standard patch test series in 42 centers of a Central European Network were retrospectively evaluated. Analyses were done for synchronous positive reactions of graded strength to nickel sulfate, fragrance mix, and to those five allergens that followed in frequency of positive results. All seven allergens selected were not related by chemical structure or exposure. Descriptive univariate and bivariate analyses as well as a polytomous logistic regression analysis were performed. Odds ratios with 95% confidence intervals were calculated. RESULTS: With an increasing strength of a positive reaction to nickel or to fragrance mix the likelihood of further positive reactions to unrelated contact allergens increased significantly, and the mean strength of such additional reactions raised steadily with an increasing strength of a nickel or fragrance reaction. CONCLUSIONS: Our findings support the idea that patients who respond with a strong patch test reaction may have a particular general disposition to acquire contact sensitivity to additional unrelated allergens. They should therefore not only be advised to avoid their known allergen but in addition to minimize exposure other contact allergens.

Adolescent↗
PubMed2006

Type-IV sensitization profile of individuals with atopic eczema: results from the Information Network of Departments of Dermatology (IVDK) and the German Contact Dermatitis Research Group (DKG).

UNLABELLED: The role of atopic eczema (AE) as risk factor for the development of allergic contact dermatitis is discussed controversially, as well as its influence on patch test results due to increased irritability. In this study, we analysed the pattern of positive patch test results to most frequent contact allergens in patients with AE (n = 9020) and age matched nonatopic (n = 15,263) individuals. The pattern and the frequencies of the observed sensitizations did not differ greatly from nonatopic individuals. Bufexamac is an exception: in AE patients sensitization is observed three times more often. For the other substances tested only minor differences were detected. Moreover, the frequencies of single, double or polyvalent sensitizations were nearly identical between the two groups. The analysis of the anatomical sites of dermatitis shows differences between the groups: in AE patients, the face (7.2%) and hand dermatitis (6.6%) was more common, and leg dermatitis (4.0%) less common. Analysis of occupation, suspected allergen source, and accompanying factors revealed no major differences between the both groups. CONCLUSION: The chronic and long-term exposure to external drugs and emollients presumably carries a risk for sensitization against specific contact allergens in AE patients. However, the sensitization of contact allergens differs surprisingly little between patients with or without AE.

Allergens↗
PubMed2006

A high-positive patch test load correlates with further positive patch test reactions irrespective of their location.

BACKGROUND: Patch testing is the standard clinical procedure to prove contact sensitization. It is a common practice to attach multiple patch tests at the same time. However, synchronous reactions to unrelated allergens may not be completely unassociated. If so, the reaction in a given test field might be influenced by other positive test reactions in a distance-related degree. This article analyses whether there is a distance-related effect of synchronous positive patch test reactions on the outcome of a target patch test. METHODS: Data collected from patients patch tested for diagnostic purposes with 15 standard allergens attached in a specific pattern between 1992 and 2004 in 20 centres in a Central European network were retrospectively evaluated. The association between the target patch test result (allergic vs negative reaction to the thiuram mix) and the number and cumulated strength of synchronous positive reactions (positive patch test load) to allergens placed in nearby or distant positions to the target patch was analysed by using logistic regression analysis. RESULTS: The likelihood of a positive reaction to thiuram mix significantly increased with an increasing synchronous positive patch test load generated by positive reactions to allergens unrelated to thiuram mix. The effect of allergens neighbouring the target allergen was not significantly stronger than that of allergens placed in distant positions. CONCLUSION: For the interpretation of patch test results, the potentially enhancing effects of a synchronous positive patch test load should be considered. The local distribution of the patches on the back is, however, not critical.

Dermatitis, Contact↗
PubMed2005

[A common and insidious side-effect: allergic contact dermatitis caused by bufexamac used in the treatment of dermatitis. Results from the Information Network of Departments of Dermatology (IDVK)].

BACKGROUND AND OBJECTIVE: Bufexamac is a non-steroidal, anti-inflammatory drug used in the topical treatment of atopic dermatitis, stasis dermatitis and perianal eczema. The substance is known to cause severe allergic contact dermatitis (ACD) as an adverse effect (AE), which may be indistinguishable from the eczema which is to be treated. Hence the diagnosis of this AE is often considerably delayed. In order to estimate the quantitative importance of ACD to bufexamac, data of the Information Network of (German) Departments of Dermatology (IVDK) from July 1999 to December 2004 were analysed. PATIENTS AND METHODS: During the study period, 39,392 unselected patients from 40 German departments of the IVDK were patch tested with bufexamac (5 % pet). The results of the reading after 72 hours were analysed. The dichotomized patch test result was further assessed for possible risk factors from the patients' history and clinical diagnosis by Poisson regression analysis. RESULTS: In 560 of 39,392 patients contact allergy to bufexamac was diagnosed, i. e. 1.4 % (95 % confidence interval: 1.3 - 1.5), standardized for sex and age. The Poisson regression analysis revealed a significantly increased risk associated with the following factors: multiple sensitization, perianal eczema, underlying atopic dermatitis, leg dermatitis, female gender and residence in areas of Germany other than Eastern Germany. The latter observation can be explained by low prescription rates in Eastern Germany. CONCLUSION: Bufexamac is an important allergen. Extrapolating the frequency of 1.4 % in our data to the whole German population by the CE-DUR approach yields an estimate of about 6000 cases per year. In view of the high frequency of sensitization, the pitfalls in diagnosis, the severity of the course of disease and the lack of efficacy of this drug, the risk to benefit ratio is obviously critical.

Administration, Topical↗
PubMed2005

Contact allergy to neomycin sulfate: results of a multifactorial analysis.

PURPOSE: To perform a comprehensive, multifactorial analysis of potential risk factors (demographic and clinical) for contact allergy to neomycin sulfate, a common adverse reaction resulting from the topical use of this drug; especially in some subgroups of the population. METHODS: Retrospective analysis of allergy test data of the Information Network of Departments of Dermatology (IVDK, www.ivdk.org) between 1998 and 2003, including all patients patch tested with a standard screening series because of suspected allergic contact dermatitis (ACD). As one outcome, a positive (allergic) test reaction to neomycin sulfate was considered. An alternative outcome included only those patients with a positive test to neomycin sulfate and a final diagnosis of ACD. The association between outcome and potential risk factors was analyzed with Poisson regression analysis, deriving prevalence ratios (PR) as risk estimates. RESULTS: Of the 47,559 patients tested, 2.5% had positive reactions to neomycin sulfate, while in 1.1% ACD was additionally diagnosed. The results of the multifactorial analysis indicated that the risk of both outcomes decreased slightly during the period covered; was higher among patients with leg dermatitis; varied significantly with age and increased progressively with the number of additional positive reactions to other standard series allergens. Cross-reactivity to other, selectively tested, aminoglycoside antibiotics was substantial (kappa = 0.67; 95%CI: 0.63-0.71) for framycetin sulfate, to low (kappa = 0.33; 95%CI: 0.27-0.37) for gentamicin sulfate. CONCLUSIONS: The prevalence of contact sensitization to neomycin sulfate was noteworthy among patients patch tested in the IVDK centers. Supplementing clinical epidemiology, neomycin contact allergy has been estimated to be relatively common even on the level of the unselected population (prevalence approx. 1%). Hence, the topical use of neomycin sulfate by patients should be carefully monitored, considering its potential to induce ACD, with emphasis on subgroups at risk.

Administration, Topical↗
PubMed2005

[Patch testing with the DKG standard series 2001-2004. Results from the IVDK].

Patch testing is the standard procedure to detect contact sensitivity. The most frequent contact allergens are included in the standard series. We report on current trends regarding results obtained with the standard series from 2001-2004 in Germany, Austria (Graz, Vienna) and Switzerland (Basel). This analysis includes the frequency of the most common contact allergens and other aspects such as age and gender distribution and parameters of diagnostic quality such as reaction index and positivity ratio. Information on the most common contact allergens is updated.

Adult↗
PubMed2005

Rosacea and contact allergy to cosmetics and topical medicaments--retrospective analysis of multicentre surveillance data 1995-2002.

The role of contact allergy in rosacea has rarely been investigated. In this retrospective study, 361 out of 76,697 patients tested and documented by the Information Network of Departments of Dermatology between 1995 and 2002 had rosacea. Patch tests included standard series and constituents of cosmetics and topical medicaments. 118/361 had additionally been patch tested with their own cosmetics/medicaments. Positive reactions occurred to nickel (II) sulfate in 9.3%, fragrance mix in 8.8%, thimerosal in 6.9%, Myroxylon pereirae resin in 5.9%, potassium dichromate in 4.6% and propolis in 2.8%. Whereas rosacea patients had a significantly higher risk of contact allergy to propolis compared to the remaining patients, in an age- and sex-adjusted analysis, contact allergy to nickel was significantly less frequent in this group. For Lyral, the risk was elevated, albeit not significantly. Only 2/329 patients were positive to neomycin sulfate and 1/100 to gentamicin sulfate, among the panel of (topical) antibiotics tested. Among 118 patients tested with their own products, 3 were tested to metronidazole, 1 reacting positively. Irritant or doubtful patch test reactions were provoked by various substances (vehicles, oxidants and preservatives of various creams), which might also be clinically important, considering the heightened sensitivity of rosaceous skin.

Administration, Cutaneous↗
PubMed2005

Quantitative patch and repeated open application testing in methyldibromo glutaronitrile-sensitive patients.

Contact allergy to methyldibromo glutaronitrile (MDBGN), often combined with phenoxyethanol (PE) (e.g., Euxyl K 400), increased throughout the 1990s in Europe. Consequently, in 2003, the European Commission banned its use in leave-on products, where its use concentration was considered too high and the non-sensitizing use concentration as yet unknown. The 2 objectives of the study are (a) to find a maximum non-eliciting concentration in a leave-on product in MDBGN/PE-sensitized patients, which could possibly also be considered safe regarding induction and (b) to find the best patch test concentration for MDBGN. We, therefore, performed a use-related test (ROAT) in patients sensitized to MDBGN/PE (n = 39) with 3 concentrations of MDBGN/PE (50, 100 and 250 p.p.m. MDBGN, respectively). A subset of these patients (n = 24) was later patch-tested with various concentrations (0.1, 0.2, 0.3 and 0.5% MDBGN, respectively). 15 patients (38%, 95% confidence interval (CI) = 23-55%) had a negative and 24 (62%; 95% CI = 45-77%) a positive overall repeated open application test (ROAT) result. 13 reacted to the lowest (50 p.p.m.), 8 to the middle (100 p.p.m.) and 3 to the highest concentration (250 p.p.m.) only. In those 13 reacting to the lowest ROAT concentration, dermatitis developed within a few days (1-7). The strength of the initial and the confirmatory patch test result, respectively, and the outcome of the ROAT were positively associated. Of the 24 patients with a use and confirmatory patch test, 15 reacted to 0.1% MDBGN, 16 to 0.2%, 17 to 0.3% and 22 to 0.5%. With the patch test concentration of 0.5%, the number of ROAT-negative patients but patch-test-positive patients increases considerably, particularly due to + reactions. A maximum sensitivity of 94% (95% CI = 70-100%) is reached with a patch test concentration of 0.2%, and is not further improved by increasing the concentration. However, the specificity decreases dramatically from 88 (95% CI = 47-100%) with 0.2% to a mere 12.5% (95% CI = 0-53%) with 0.5%. It can be concluded (a) that for MDBGN 0.2% is very likely the best patch test concentration and (b) that 50 p.p.m. in a leave-on product can elicit contact dermatitis in sensitized persons. We were, therefore, unable to find a safe, still microbicidal, concentration for leave-on products. By contrast, with other contact allergens, dose-response use tests may be able to identify a non-eliciting concentration, which could give valuable clues to a non-inducing (i.e., safe) concentration in products.

Adult↗
PubMed2005

The European standard series in 9 European countries, 2002/2003 -- first results of the European Surveillance System on Contact Allergies.

Since January 2001, the European Surveillance System on Contact Allergies (ESSCA), supported by European Union funding (contract QLK4-CT-2001-00343), has started to collect patch-test data. This comprises a standardized clinical history and the patch-test results using the European standard series, from 17 centres in 9 European countries listed above. In 2002 and 2003, 10 511 patients' test results have been pooled and analysed. The anamnestic data partly reflect the subspecialties of some centres. The most common allergen was nickel sulfate (17.3%); however, large international variations were observed. The prevalence of contact allergy to Myroxylon pereirae resin (balsam of Peru) (5.8%) is coming close to the frequency found with the fragrance mix (6.4%). Regarding contact allergy to chromium compounds, different frequencies were noted in the 2 centres focused on occupational dermatitis (2.3% in the FIOH versus 7.4% in the Nofer Institute). These most likely reflect the beneficial effect of addition of ferrous sulfate in one, but not the other country. As differences may partly be due to different patch-test reading, standardization may need to be refined further. By providing post-marketing surveillance in the field of contact allergy, ESSCA will meet its objective of increased consumer safety across Europe.

Adult↗
PubMed2005

A multifactorial analysis of concurrent patch-test reactions to nickel, cobalt, and chromate.

BACKGROUND: Previous research indicates that positive patch tests to nickel (II) sulphate, cobalt (II) chloride and potassium dichromate commonly occur together. METHODS: To further examine the relationship between nickel, cobalt, chromate, and the factors that may potentially be related to concurrent sensitizations to two or all three metal allergens, data from the Information Network of Dermatology Departments have been investigated. RESULTS: Women had a higher conditional odds of concurrent nickel-cobalt (OR = 6.80; 95% CI: 5.65-8.19) and nickel-chromate (OR = 2.13; 95% CI: 1.67-2.72) reactions than men. Construction workers had a significantly higher odds of cobalt-chromate reactions (OR = 13.89; 95% CI: 10.36-18.64), while the odds of isolated cobalt allergy was only 0.92 (95% CI: 0.48-1.74). Patients with underlying atopic eczema/dermatitis syndrome had a 40-90% higher chance of any positive outcome, which involved chromate. Polysensitization, defined as the number of positive reactions to standard series substances other than nickel, cobalt, and chromate, was also significantly associated with the concurrent reactions; moreover, steady and significant effect gradients were noted. CONCLUSIONS: This research confirms the occupational nature of cobalt-chromate concurrent reactions, in particular, in construction workers. Polysensitization, which is considered to represent susceptibility to delayed-hypersensitivity in general, is also associated with the concurrent reactions to the metals. Hence, not only coupled exposure, but also individual susceptibility may be responsible for concurrent reactions to metals in man.

Adult↗
PubMed2004

Iodopropynylbutyl carbamate 0.2% is suggested for patch testing of patients with eczema possibly related to preservatives.

BACKGROUND: Iodopropynyl butylcarbamate (IPBC) is a new preservative in medical and cosmetic leave-on products. Although cases of allergic contact dermatitis to IPBC have been reported, it is not known whether the usual test concentration of 0.1% is appropriate for screening tests with IPBC. OBJECTIVES: To determine the concentration of IPBC that should be used in screening patch tests. METHODS: An analysis was made of data filed by 26 centres of dermatology on patch tests performed with one or two concentrations of IPBC (0.1%, 0.2%, 0.3% or 0.5%) in 8106 unselected patients. Criteria used to determine the best test concentration of IPBC were the reaction index, the positivity ratio, the rate of crescendo reactions, and the relations between IPBC reactions and the MOAHLFA index irritant reactions to sodium lauryl sulphate (SLS), and allergic reactions to other contact allergens including preservatives. RESULTS: IPBC 0.1%, 0.2%, 0.3% and 0.5% yielded 0.5%, 0.8%, 1.3% and 1.7% positive reactions, but this increase was accompanied by an even greater increase in doubtful and irritant reactions. These figures and the other criteria examined suggested the range of suitable test concentrations of IPBC to lie between 0.2% and 0.3%. A detailed analysis of MOAHLFA indices and of associations between reactions to IPBC and reactions to other allergens and to SLS showed that most of the positive reactions to IPBC 0.2% can be assumed to be allergic ones and that with IPBC 0.2% fewer false-positive reactions can be expected than with IPBC 0.3%. CONCLUSIONS: Patch testing with IPBC 0.2% is suggested for patients with eczema possibly related to preservatives.

Adult↗