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.

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.

Risk factors for contact allergy to nickel - results of a multifactorial analysis

To quantify the independent impact of potential risk factors for nickel contact allergy (NCA), a multifactorial Poisson regression analysis of standardized anamnestic and patch test data (with nickel sulfate, 5% in petrolatum) was performed, comprising 74 940 patients assessed in the 33 German and Austrian contact dermatitis units of the Information Network of Departments of Dermatology (IVDK) between 1992 and 2000. NCA was observed in 15.5% patients. Female sex was the strongest risk factor (prevalence ratio 3.74, 95% CI: 3.51-3.98). Risk increased monotonically and significantly with decreasing age. Atopic dermatitis was not a risk factor. The year of patch test had no influence on NCA risk. Significant variation of risk between occupations was observed. In conclusion, our multifactorial analysis was able to quantify the impact of established risk factors and additionally address other, e.g. occupational, factors yet unidentified.

When should a substance be designated as sensitizing for the skin ('Sh') or for the airways ('Sa')?

In the List of MAK and BAT Values compounds are designated with 'Sa' ('sensitizing for the airways') or 'Sh' ('sensitizing for the skin') if, according to scientific evidence, they are allergens. Mainly based on suggestions by a WHO working group and based on our own experience, extended criteria have been elaborated by the working group 'skin and allergy' of the Commission of the Deutsche Forschungsgemeinschaft for the Investigation of Health Hazards of Chemical Compounds in the Work Area, which are presented in this article. They serve as guidelines for deciding which substances have to be labelled 'Sa' and 'Sh', respectively, for the prevention of sensitization and subsequent allergic diseases in workers. Although in some special cases their strict application may not be deemed necessary or possible, the proposed new criteria should be used to make the procedure of classification of substances: 1) more rational, 2) more consistent, 3) more comprehensible, and 4) more transparent. This paper informs readers working scientifically or administratively in this field and invites a critical discussion of the issue.

Epidemiology of contact allergy: an estimation of morbidity employing the clinical epidemiology and drug-utilization research (CE-DUR) approach

Clinical epidemiology (CE) is considered unable to estimate morbidity concerning either contact sensitization (CS) or allergic contact dermatitis (ACD) at the population level. Drug-utilization research (DUR) methods estimate the morbidity of suitable diseases based on prescription data for disease-specific drugs. Our objective was to estimate population figures for incidence and prevalence of ACD and CS based on sales data for patch test material in Germany and on patient data from the Information Network of Departments of Dermatology (IVDK). Approximately 600000 standard series are sold per year in Germany, according to the 2 main manufacturers. This raw sales figure was corrected for certain effects (discarded preparations, proportion of formerly patch-tested patients, proportion of patients with ACD seeking medical advice) to obtain an estimate of the denominator of patients eligible for patch testing annually, and combined with patch test results from the Information Network of Departments of Dermatology (IVDK). In 17.8% (of 9266 IVDK patients) ACD was established. Extrapolated to the general population, an incidence of ACD of between 1.7 and 7 per 1000 per year was estimated, depending on whether conservative or more liberal assumptions concerning the above effects were made. Of 78067 IVDK patients tested between 1992 and 2000, 46.8% had at least 1 positive reaction (+ to + + +), and 22.7% had at least 1 stronger positive reaction (+ + or + + +). The 9-year prevalence of CS was estimated to lie between 4.0% and 16.6% for the first outcome, and between 2.0% and 8.1% for the second. Concerning single allergens, 1.9-4.5 million individuals are probably sensitized to nickel, and 1.4-3.4 million to fragrance mix among the German population of 82 million inhabitants. The morbidity data found in this study are in good accordance with data from population-based epidemiological studies. In comparison to these, the CE-DUR approach seems to be an economically feasible method to estimate continuously the population impact of ACD and CS.

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.

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.

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.

The preservative iodopropynyl butylcarbamate: frequency of allergic reactions and diagnostic considerations

The preservative iodopropynyl butylcarbamate (IPBC) (0.1% in petrolatum) was tested in 4883 consecutive patients for 18 months between January 1998 and June 1999. With regard to the MOAHLFA-Index, the study population comprised 37% males; 17% with occupational and 19% with atopic dermatitis; 31% with hand, 10% with leg and 17% with face dermatitis; 61% were age 40 and above. According to readings at D3, 0.3% were allergic to IPBC, with 14 + and 2 + + reactions. Doubtful or irritant reactions occurred twice as frequently. Patients exposed for 24 h (n = 1814) reacted less frequently (0.1%) than the remaining patients exposed for 48 h (0.5%). Considering the possibility that a certain proportion of + reactions could be false positive, the reaction pattern was evaluated. More than 80% of the positive reactions displayed a crescendo or plateau time pattern. Furthermore, 18 of 43 doubtful reactions (?) appeared as late as D3 (thus, these could be false negative), whereas the majority of doubtful reactions occurred earlier and displayed a decrescendo pattern (corresponding to a typical irritant pattern). In conclusion, the large proportion of '?' reactions may be due not only to the irritant potential of the substance, but also to test concentrations not being high enough to elicit an allergic reaction. We propose that higher concentrations of IPBC (0.3%) should be evaluated in a study also addressing suitable validation tests like ROAT or PUT.

Glyoxal is an important allergen for (medical care) cleaning staff

While disinfection is essential in medical practice, it carries the risk of serious adverse effects, including allergic contact dermatitis. To assess the current importance of glyoxal [CAS 107-22-2] as occupational allergen, a retrospective descriptive analysis of records of an occupational dermatitis clinic in Osnabrück and of national surveillance data of the Information Network of Departments of Dermatology (IVDK) in Germany and Austria was performed. Of 189 highly selected patients with occupational dermatitis tested with glyoxal (1% in water or, as trimer, 1% in petrolatum) in Osnabrück, 11 had positive reactions to glyoxal, which were occupationally relevant in 9 cases. Causative occupations included mainly nursing and room cleaning. In a less selected population of 2626 additional patients tested in other centres of the IVDK, 40 further positive reactions to glyoxal were observed. Concomitant sensitisation to glutardialdehyde and formaldehyde, respectively, was frequently observed. In conclusion, glyoxal should be tested in all patients with contact dermatitis working in occupations with possible exposure to respective disinfecting/cleaning agents.

Associated positive patch test reactions to standard contact allergens

BACKGROUND

Patch testing with a standard allergen series often yields positive reactions to more than 1 allergen in a patient.

OBJECTIVE

To identify all significantly associated pairs of positive reactions and to assess their relation to the strength of the reactions and to the irritative potential of the allergens.

METHODS

Based on the filed data of 57,822 patients, associations between positive reactions to 2 different allergens were quantified with odds ratios. Statistical methods included Fisher's exact test, the Bonferroni adjustment to account for the effect of multiple testing, and the Spearman rank correlation.

RESULTS

Out of the 32,779 patients with complete readings of 24 standard allergens, 7,501 had shown more than 1 positive reaction. Statistically significant associations were detected for 166 out of the 276 possible different combinations of 2 distinct positive reactions, including combinations that had not been identified before. Patients with a strong reaction or a positive reaction to an allergen with a high irritative potential tended to have additional positive reactions to further allergens more often than others, but the number of significant associations was not dependent on these parameters.

CONCLUSION

There are more significant associations that have to be taken into account for patch testing than has been known so far. Although irritation can favor a higher number of positive reactions, significant associations of positive reactions to distinct allergens are probably caused by other mechanisms that require further analyses.

Association between occupation and contact allergy to the fragrance mix: a multifactorial analysis of national surveillance data

OBJECTIVES

To assess the role of potential (occupational) risk factors for fragrance contact allergy (FCA). Most studies assessing the range of contact sensitisation in various clinical populations found the fragrance mix, a good screening tool for the detection of FCA in general, to be one of the leading allergens. The role of occupational exposure to fragrances is, however, yet unclear.

METHODS

Firstly, crude analyses of the prevalence of FCA in various occupational fields including all 57,779 patients patch tested in the participating centres of the Information Network of Departments of Dermatology (IVDK) between January 1992 and December 1998. Secondly, a multifactorial Poisson regression analysis of these patients, including several potential risk factors.

RESULTS

(a) The proportion of patients with FCA varied greatly between different occupational groups from 2.5% to 17.4%, (b) the highest occupational risk of FCA was associated with work as a masseur or physiotherapist, metal furnace operator, potter or glass maker etc, or geriatric nurse, (c) non-occupational factors that influenced risk of FCA included atopy, female sex, several sites, in particular the axillae, and increasing age.

CONCLUSIONS

Occupations with a high risk of FCA were identified as targets of preventive action--that is, the substitution of scented products with fragrance free materials with which to work (skin disinfectants, cleaning solutions, personal care products) wherever possible.

Another look at seasonal variation in patch test results. A multifactorial analysis of surveillance data of the IVDK. Information Network of Departments of Dermatology

There is conflicting evidence concerning seasonal variability of patch test results and no evidence concerning the influence of season on weak-positive, possibly false-positive, irritant reactions, which was analysed in the present study. Data collected in the German Information Network of Departments of Dermatology (IVDK) 1992 to 1997 were combined with external environmental data on temperature and absolute humidity in Germany, and bivariate as well as logistic regression analyses performed concerning the association between reactivity to selected allergens and air temperature and absolute humidity on the respective days of patch testing. Between 39,239 and 41,629 patients had been tested with the 4 allergens considered here. Only formaldehyde exhibited a distinct increase in questionable or irritant as well as weak-positive reactions associated with dry, cold weather. Methylchloroisothiazolinone/methylisothiazolinone and lanolin alcohol showed only a weak, and epoxy resin no, association with climatic conditions. The results indicate that weak-positive reactions, at least to formaldehyde as a prototype of an allergen which is at the same time a marginal irritant, may sometimes be irritant rather than allergic. Patients showing these should be re-tested to improve the poor reproducibilty observed with this allergen.

Patch testing with methyldibromoglutaronitrile

BACKGROUND

The combination of methyldibromoglutaronitrile (MDBGN) and phenoxyethanol (PE) is widely used as a preservative in body care products. Sensitization rates to MDBGN have increased parallel to its increasing use in cosmetics, skin care products, and moist toilet paper since the early 1990s, whereas PE is obviously not a sensitizer. The optimum patch preparation for diagnosing a contact allergy to MDBGN is still a matter of debate.

OBJECTIVE

This study was performed to assess an adequate patch test concentration for MDBGN/PE and MDBGN.

METHODS

Based on previous results from other countries, the German Contact Dermatitis Research Group (DKG) performed parallel patch tests with MDBGN/PE 0.5% in petrolatum (pet.) and 1% pet. in 4,615 patients and with MDBGN 0.1% pet. and 0.3% pet. in 988 patients. The results of these tests, performed in routine patch testing, were collected and analyzed be the Information Network of Departments of Dermatology (IVDK).

RESULTS

Comparing MDBGN/PE 0.5% pet. with 1.0% pet., the percentage of patients showing a positive test reaction increased from 2.3% to 3. 5% (P <.001), mainly because of an increase in weak positive reactions. The reaction index remained stable at 0.54. Comparing MDBGN 0.1% pet. with 0.3% pet., the percentage of patients with positive reactions increased from 1.4% to 3.3% (P <.001), and the reaction index decreased from 0.33 to -0.10. With the lower test concentration, 79% of the positive reactions were only +, with the greater concentration, this was true of 64%.

CONCLUSION

Testing MDBGN/PE 1.0% pet. shows additional cases of contact allergy to MDBGN that would have remained undetected with MDBGN 0.5% pet. The greater test concentration seems to have no disadvantages in quality. The DKG decided to keep MDBGN/PE 1.0% pet. in the standard series. MDBGN 0.3% pet. leads to far more doubtful or irritant test reactions than MDBGN 0.1% and may produce false-positive patch test results. Therefore, the DKG recommends testing MDBGN 0.3% pet only in special cases.

Homozygous gene deletions of the glutathione S-transferases M1 and T1 are associated with thimerosal sensitization

OBJECTIVE

Thimerosal is an important preservative in vaccines and ophthalmologic preparations. The substance is known to be a type IV sensitizing agent. High sensitization rates were observed in contact-allergic patients and in health care workers who had been exposed to thimerosal-preserved vaccines. There is evidence for the involvement of the glutathione system in the metabolism of thimerosal or its decomposition products (organomercury alkyl compounds). Thus detoxification by polymorphically expressed glutathione S-transferases such as GSTT1 and GSTM1 might have a protective effect against sensitization by these substances.

METHODS

To address this question, a case control study was conducted, including 91 Central European individuals with a positive patch-test reaction to thimerosal. This population was compared with 169 healthy controls and additionally with 114 individuals affected by an allergy against para-substituted aryl compounds. The latter population was included in order to test whether possible associations were due to substance-specific effects, or were a general feature connected with type IV immunological diseases. Homozygous deletions of GSTT1 and GSTM1 were determined by polymerase chain reaction.

RESULTS

Glutathione S-transferase M1 deficiency was significantly more frequent among patients sensitized to thimerosal (65.9%, P = 0.013) compared with the healthy control group (49.1%) and the "para-compound" group (48%, P = 0.034). Glutathione S-transferase T1 deficiency in the thimerosal/mercury group (19.8%) was barely elevated versus healthy controls (16.0%) and the "para-compound" group (14.0%). The combined deletion (GSTT1-/GSTM1-) was markedly more frequent among thimerosal-sensitized patients than in healthy controls (17.6% vs. 6.5%, P = 0.0093) and in the "para-compound" group (17.6% vs. 6.1%, P =0.014), revealing a synergistic effect of these enzyme deficiencies (healthy controls vs. thimerosal GSTM1 negative individuals, OR = 2.0 [CI = 1.2-3.4], GSTT1-, OR = 1.2 [CI = 0.70-2.1], GSTM1/T1-, OR = 3.1 [CI = 1.4-6.5]).

CONCLUSIONS

Since the glutathione-dependent system was repeatedly shown to be involved in the metabolism of thimerosal decomposition products, the observed association may be of functional relevance.

Downward trend of sensitization to glyceryl monothioglycolate in German hairdressers. IVDK study group. Information Network of Departments of Dermatology

BACKGROUND

Due to a high incidence of cases of (occupational) sensitization to glyceryl monothioglycolate (GMT), products containing this compound were withdrawn from the German market some 8 years ago.

METHODS

We analyzed the data of the Information Network of Departments of Dermatology in Germany which included 1, 336 hairdressers who had been tested with GMT (1% in petrolatum) between 1992 and 1998.

RESULTS

The proportion of hairdressers reacting positively to GMT fell from initially 45% in 1992 to less than 20% in 1997 and 1998.

CONCLUSION

This most likely reflects the above-mentioned preventive action.

N-acetyltransferase 1 and 2 polymorphisms in para-substituted arylamine-induced contact allergy

Sensitization to arylamines such as p-phenylenediamine is frequently diagnosed in patients with allergic contact dermatitis. Reactive metabolites of p-phenylenediamine might be produced in the skin by O-acetylation of N-hydroxylamines catalysed by local N-acetyltransferases (NATs). In this study, we tested whether genetic polymorphisms of NATs, which are known to affect enzyme activity, may influence the susceptibility to para-substituted arylamine-induced contact eczema. Using polymerase chain reaction and restriction enzyme analysis, the distribution of polymorphisms of NAT1 and NAT2 was investigated in 88 patients sensitized to para-substituted aryl compounds and 123 healthy controls. NAT2 rapid acetylators, i.e. carriers of the NAT2*4 wild-type allele, were more common in the contact allergy (44%) than in the healthy control group [30%; P = 0.042, odds ratio 1.9 (95% confidence interval, CI 1. 05-3.27)]. Slow acetylators carrying the NAT2*5b/2*6a genotype were significantly less frequent among patients [13% vs. 38% in controls; P = 0.009, odds ratio 0.39 (95% CI 0.19-0.78)]. The carriage rate of the NAT1*10 allele, which is supposed to encode for a rapid NAT1 phenotype, was not significantly different between patients and controls [43% vs. 36%; odds ratio 1.5 (95% CI 0.88-2.68)]. Interactions between NAT2*4 and NAT1*10 were suggested by the increased frequency of the NAT2*4/NAT1*10 haplotype in patients (27%) compared with controls [15%; P = 0.039, odds ratio 2.1 (95% CI 1.04-4.04)]. As the NAT1 and NAT2 encoding genes are located in close proximity on chromosome 8p22, the latter finding could at least partly be due to genetic linkage. In fact, a linkage disequilibrium between NAT2*4 and NAT1*10 was observed in the contact allergy (P = 0.0025) and in the control group (P = 0.042). Our data indicate an association between the NAT2*4/NAT1*10 haplotype and contact sensitization to para-substituted aryl compounds. Therefore, acetylation may either enhance contact sensitization or NAT2*4 and NAT1*10 might be linked to an unknown susceptibility factor.

Increase in sensitization to oil of turpentine: recent data from a multicenter study on 45,005 patients from the German-Austrian Information Network of Departments of Dermatology (IVDK)

Contact allergy to oil of turpentine was reported to have become rare. However, the evaluation of standardized data of 45,005 patients tested 1992-1997 in 30 Dermatological Centers associated with the German-Austrian Information Network of Departments of Dermatology (IVDK) showed an increase in positive patch test reactions to turpentine from 0.5% during the years 1992-1995, up to 1.7% in 1996 and 3.1% in 1997. In particular, 17,347 patients tested in 1996-1997 were evaluated in detail by comparing 431 individuals with positive patch test reactions with the rest of the group found negative to turpentine. Using the so-called MOAHLFA index, the following characteristics were shown. Turpentine allergy (a) was found to be significantly less frequent in men and in patients with occupational dermatitis, (b) showed no difference in its association with atopic dermatitis, (c) patients with turpentine allergy had significantly less symptoms of the hands, more symptoms of the legs or in the face and (d) were significantly more often aged over 60 years. Also, patients sensitized to turpentine had increased rates of additional sensitizations. The definite reason for the increase in turpentine sensitization in the population tested here is not clear. Therefore, a detailed exposure analysis is necessary; the new increase in turpentine allergies may be due to popular topical remedies or household chemicals.

Contact allergies in healthcare workers. Results from the IVDK

Healthcare workers often suffer from occupational skin disease frequently caused by allergic sensitization. Therefore the patch-test results and important patient history items of 31,849 patients recorded between 1992 and 1995 in the 24 allergy departments participating in the Information Network of Departments of Dermatology (IVDK) were evaluated. Significantly increased sensitization rates common to the healthcare sector as a whole were found for the vaccine preservative thiomersal (12.6% vs. 4.9%), the surface and instrument disinfectants glutardialdehyde (9.9% vs. 2.6%), formaldehyde (3.6% vs. 2.1%) and glyoxal (4.2% vs. 1.4%), and for the compounds of the thiuram mix (6.7% vs. 2.6%) present in protective gloves. Formaldehyde seems to lose its importance, but glyoxal must be added to the list of occupational allergens in the healthcare sector. In addition, occupation-specific sensitization was observed, with fragrances in massage therapists (16.1% vs. 10.6%) and nurses (13.8% vs. 11.4%), as well as with methacrylates in dental technicians. The often assumed importance of drugs as type-IV allergens was not confirmed, at least in terms of quantity. The identification of subgroups of increased risk and of occupation-specific allergens could be the basis of targeted preventive action in the healthcare sector.

Genotype and phenotype of N-acetyltransferase 2 (NAT2) polymorphism in patients with contact allergy

We investigated whether patients with contact allergy differed from non-contact-allergic, non-atopic controls with regard to genotype and phenotype of the polymorphic enzyme N-acetyltransferase 2 (NAT2). 55 contact-allergic patients recruited from the Information Network of Departments of Dermatology (IVDK) were compared to 85 controls from among local health care personnel. NAT2 activity was calculated from HPLC analysis of the ratio of the caffeine metabolites 5-acetylamino-6-formylamino-3-methyluracil (AFMU) and 1-methylxanthine (1MX) in the urine. NAT2 genotype was determined by polymerase chain reaction (PCR). A statistically significantly increased proportion of rapid acetylators was found in contact-allergic patients. This may have 2 possible implications: acetylation may enhance contact sensitization; or NAT2 status may be a genetic marker for contact sensitizability.

Patch testing with preservatives, antimicrobials and industrial biocides. Results from a multicentre study

Preservatives are biologically reactive substances, and their allergenic potential has been known for a long time. This study examined the role of different preservatives in a large number of patients with suspected allergic contact dermatitis. Patch test data and data from the patients' history were collected from the 24 departments participating in the Information Network of Departments of Dermatology from 1 January 1990 to 31 December 1994. Patch test data from 28,349 patients tested with preservatives of the standard series (SS), from 11,485 patients tested additionally with a preservative series (PS), and from 1787 patients tested with an industrial biocide tray (IB) were evaluated. Sensitization rates (standardized) of the SS preservatives were all > 1%, with thiomersal rating highest (5.3%), the parabens lowest (1.6%), and the remainder (chlormethylisothiazolinone/methylisothiazolinone, formaldehyde and methyldibromoglutaronitrile/phenoxyethanol (MDBGN/PE)) in the range of 2%. The most important allergens of the PS were, in women, alkylaminobenzoate (contained in milking fat) (2.5%), MDBGN/PE (2.2%), benzalkonium chloride (1.8%), chloracetamide (1.4%), diazolidinyl urea (1.3%), octylgallate (1.2%) and Bronopol (1.1%). In men rates differed only with regard to alkylaminobenzoate (0.9%). Patients tested with the IB series reacted most often to methylene-bis-thiocyanate (5%), but with a reaction index of -0.7, many reactions were most probably false positives. A further seven preservatives, mostly formaldehyde-releasers used in cutting fluids, gave sensitization rates of between 1% and 3%. Glutaraldehyde, not contained in the series but often tested additionally, showed a remarkable increase in sensitization during the study period. Health care personnel were frequently affected. Altogether, this study identified areas of concern within the different groups of preservatives. The overall impact of most of the preservatives on public health seems to be low, but for diagnostic reasons preservatives must be included in patch test series.

[Differentiated contact allergy lists serve in quality improvement]

Through cooperation between the German Contact Dermatitis Research Group (DKG) and the Information Network of Departments of Dermatology (IVDK), results of standardized patch tests performed by the participating centres are centrally recorded in Germany. For this study, data from 24 departments of dermatology (19678 patients) were evaluated retrospectively and separately for 1995 and 1996. With decreasing frequency, nickel, fragrance mix, balsam of peru, and thimerosal yielded positive reactions most often; surprisingly high numbers of positive reactions were also seen with amerchol L-101 and palladium. Differentiated lists of allergens were compiled for 1995, referring to subgroups of patients (defined by gender, age, localization of eczema, geographical region, occupation, sensitization) and particular problems. In men, percentages of positive reactions were markedly lower for nickel, fragrance mix and balsam of peru than in women. Younger patients reacted more often to thimerosal and older ones to topical medical preparations. Medical allergens were also often positive in patients with leg eczema, whereas occupational allergens were found more frequently in patients with hand eczema. A comparison of positive reactions obtained in distinct geographical regions was problematic because of differences between test populations. The spectrum of allergens found in office workers was similar to that of the whole test population. Patients with positive reactions to nickel and fragrance mix had more positive reactions to unrelated allergens than the total test population. Sex- and age-adjusted frequencies of sensitization revealed a decrease in reactions to nickel and an increase in reactions to mercury allergens from 1995 to 1996. The clinical relevance of mercury reactions was often not apparent. Differentiated lists of allergens can be used to improve the quality of diagnostic and prophylactic procedures in allergic contact dermatitis.

Epidemiology of contact dermatitis. The information network of departments of dermatology (IVDK) in Germany

In 1988, the multicenter project "Information Network of Departments of Dermatology (IVDK)", including eight university skin hospitals was founded. It now comprises 30 participating centers. At these centers, all patch test results are recorded, together with important anamnestic details and, twice a year, these are sent to the data center at the Göttingen University Skin Hospital. Regular, descriptive analyses of data collected by this epidemiological surveillance system serve the different purposes discussed in this paper: 1) observation of "sentinel events"; e.g. an increase in the proportion of patients tested who were sensitized to a certain allergen, or the identification of certain subgroups at particular risk as a starting point for further research or preventive action, and 2) advancement of good clinical practice in patch testing. In October 1996, a working group of the European Society of Contact Dermatitis (ESCD) called the "European Surveillance System on Contact Allergies (ESSCA)" was established with a similar aim of communal data collection and analysis.

National rates and regional differences in sensitization to allergens of the standard series. Population-adjusted frequencies of sensitization (PAFS) in 40,000 patients from a multicenter study (IVDK)

Sensitization rates to contact allergens vary between centers and are influenced by sex and age. Eliminating the latter 2 factors by standardization of data by age and sex, the present analysis addresses possible differences between centers remaining after elimination of these confounders, and analyzes other factors which might influence rates, e.g., the MOAHL index. Overall standardized rates were well within the range reported in previous studies and may be regarded as representing the rates of the "patch test population" in Central Europe (e.g., nickel sulfate 12.9%, fragrance mix 10.5%, balsam of Peru 7.3%, thimerosal 5.6%). For this analysis, data of those departments which contributed more than 2000 patients, or of those with extreme proportions concerning sex, age and occupational cases were selected. Patients from these 10 departments differed considerably with regard to the items of the MOAHL index and with regard to standardized rates. The items of the MOAHL index proved to be suitable for describing different patch test populations and for explaining some differences between centers. Only 'atopic dermatitis' seems to have little influence on (standardized) rates. Face dermatitis is not yet represented in the MOAHL index, but should be included, together with age > 40 years, in an extended index (acronym: MOAHLFA). Regional allergen exposure (with striking differences between East Germany, West Germany and, to a lesser extent, Austria) seems to have a great influence on the sensitization pattern observed in a department. In addition, sociological factors may influence sensitization rates, which is exemplified by high rates of nickel allergy in a socially defined subgroup. Future studies should focus on these factors, as well as on factors concerning patch test practices and quality control.

Good clinical practice in patch testing: readings beyond day 2 are necessary: a confirmatory analysis. Members of the Information Network of Departments of Dermatology

BACKGROUND

Despite general recommendations, patch test readings are still sometimes terminated at day 2.

OBJECTIVE

The consequences of failure to read patch tests after day 2 and the influence of exposure time to the patches is quantified.

METHODS

Patch test data from 9,946 patients with at least one positive reaction at day 2 or later and readings at both days 2 and 3 (from 21,062 patients tested between January 1, 1990, and December 31, 1993) collected by the Information Network of Departments of Dermatology in Germany were analyzed.

RESULTS

Comparing results at days 2 and 3, 34.5% of all positive reactions appeared at day 3 only, whereas 8.3% initially judged (weakly) positive were not considered allergic at day 3. Some standard allergens showed specific patterns. Additional positive reactions and an increasing percentage of diminishing reactions can be observed at day 4 (compared with day 3).

CONCLUSION

The importance of late reading(s) is emphasized by the proportion of potentially false judgments based on readings at day 2 only.

PAFS: population-adjusted frequency of sensitization. (I) Influence of sex and age

Sensitization rates are influenced by sex and age. Crude rates from different departments cannot be compared without taking into account these variables. However, the influence of sex and age has never been considered quantitatively. In 2 hypothetical populations with identical age-specific sensitizations rates, but differing age distributions, the influence of age on the overall sensitization rate (crude rate) is demonstrated. Furthermore, by an abstract reflection on rates, the influence of the proportions of a population category (e.g., age) on crude rates is shown (crude rate = sigma (category-specific rate x proportion of population in category)). To account for differing distributions of sex and age, we propose 2 ways. Sex-specific rates should be presented separately. Age-specific rates should be standardized. The standard rate is defined as: SR = sigma (category specific rate x proportion of standard population in category). Using a standard population with a rectangular structure (i.e., with equal proportions in each of the category (age) specific groups), the standardized rate is the arithmetic average of the category (age) specific rate. Only for simple routine evaluations can a standard population with 2 equal groups be used, namely over 39 years and under 40 years. The standardized rate can easily be calculated as SR: (positive rate (%under 40 + positive rate (%) over 39)/2. The general rule should be to use a "rectangular" standard population with 9 age groups of a 10-year sequence. By using the standardization procedure; remaining differences found in different departments can no longer be attributed to age and sex. Other factors, such as selection of patients or real epidemiological differences, can then be discussed. The application of population-adjusted frequency of sensitization (PAFS) in any publication on prevalences of sensitization is highly recommended.

Taste and olfactory disturbances after treatment for acne with isotretinoin, a 13-cis-isomer of retinoic acid

We report an olfactory disturbance after acne treatment with isotretinoin. A disturbance in taste was also reported by the patient. Examination of the nose showed no pathological findings. A CT scan was done to exclude a tumor or a lesion at the lamina cribrosa. Taste and smell examinations were performed and verified the lost qualities.