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Lab ist ein Gemisch aus den proteinspaltenden Verdauungsenzymen Pepsin und Chymosin (Rennin), welches gewohnlich aus dem Labmagen junger Wiederkauer gewonnen wird. Wahrend Pepsin auch in der Arzneimittelindustrie Einsatz findet, werden Pepsin und Chymosin gemeinsam zum Ausfallen des Milcheiweises bei der Herstellung von Kase benotigt. Davon abzugrenzen ist das mikrobielle Lab, das naturlicherweise von bestimmten Mikroorganismen gebildet wird. Dieses wird als Lab-Austauschstoff bereits seit Jahrzehnten in der Kaseherstellung verwendet. Schon seit langerem ist bekannt, dass eine berufliche Exposition gegenuber Enzymstauben zu einer Soforttypallergie fuhren kann. Die vorliegende Arbeit gibt einen Uberblick uber die Ergebnisse einer Literaturauswertung hinsichtlich der berufsbedingten atemwegssensibilisierenden Wirkung von verschiedenen Lab-Enzymen. Da es an den verschiedenen Arbeitsplatzen nicht selten zu einer gleichzeitigen Exposition gegenuber Pepsin und Chymosin bzw. mikrobiellen Labersatzstoffen kommt, wurde die entsprechende Literatur gemeinsam ausgewertet. Durch die dargestellten Studien sind Falle von spezifischer Uberempfindlichkeit der Atemwege oder der Lunge gut belegt. Durch positive Ergebnisse im Haut- und Provokationstest sowie dem Nachweis spezifischer IgE-Antikorper scheint ein immunologischer Wirkmechanismus gesichert.

1Bun des an stalt fur Ar beits schutz und Ar beits me di zin Ber lin, 2Uni ver si tats-Haut kli nik Mainz, 3Uni ver si tats-Haut kli nik Bo chum, 4In for ma tions ver bund Der ma to lo gi scher Kli ni ken Uni ver si tat Got tin gen, 5Fach ge biet Der ma to lo gie, Um welt me di zin und Ge sund heits theo rie Uni ver si tat Os na bruck, 6IVDK-Zen tra le, Haut kli nik Got tin gen, 7Uni ver si tats-Haut kli nik Er lan gen, 8Haupt ver band der ge werb li chen Be rufs ge nos sen schaf ten Sankt Au gus tin, 9Ab tei lung Kli ni sche So zial me di zin Uni ver si tats kli ni kum Hei del berg

In the 1960s an increasing number of occupational allergies in the detergent industry against the proteolytic enzyme Subtilisin were observed. In this context the high sensitization potential of enzyme dusts attracted attention. The present evaluation of literature data confirms that this is also true for cellulases. These enzymes - mostly of fungal origin - are frequently used in biotechnology. Several cases of specific airway sensitization caused by cellulases are verified by a number of studies. As symptoms, results of skin prick tests, detection of specific IgE-antibodies and results of specific bronchoprovocation tests are consistent, an immunologic mechanism seems to be confirmed.

In this review, first, the use and components of water-based metalworking fluids (WB-MWF) and neat oils, as well as the changes of WB-MWF during the working process are summarizing described. Particularly WB-MWF can cause irritant and allergic contact dermatitis in exposed metalworkers. Irritant effects on the skin are due to wet work, alkaline pH, emulsifiers and the drying up of MwF-splashes on the skin. Oxidation products of resin acids that come into the MWF via distilled tall oil in the production process, are important allergens. Further allergens in MWF are mono- and diethanolamine, formaldehyde and formaldehyde releasers, (chlor)methylisothiazolinone, benzisothiazolinone, octylisothiazolinone, iodopropynyl butylcarbamate, and probably diglycolamine. The clinical relevance of positive patch test reactions to cobalt, fragrances, and p-phenylenediamine or p-aminoazobenzene which are often observed in eczema patients exposed to WB-MWF is not fully revealed yet. Possible exposures are discussed. In every single case of suspected contact allergy due to MWF, a thorough analysis of the exposure, including private allergen sources, is obligatory. Patch test recommendations of the German Contact Dermatitis Research Group (DKG) for these patients as well as the recommendations of the task force Allergy Diagnostics in the Metal Branch for patch testing the MWF from the patient's workplace are reported. Finally, possible preventive measures are presented.

Rennet is a mixture of the proteolytic enzymes pepsin and chymosin (rennin), which is usually obtained from the fourth stomach of young ruminants. While pepsin is also used in the pharmaceutical industry, both enzymes (pepsin and chymosin) are used for the coagulation of milk protein in the manufacture of cheese. Additionally, microbial rennet, which is naturally produced by certain microorganisms, has been used as a substitute for natural rennet in the cheese production for decades. Exposure to enzyme dusts has long been known to cause occupational immediate hypersensitivities. The present paper reviews the results of an evaluation of the literature data concerning occupational airway sensitisation due to natural and microbial rennet. Cases of specific airway sensitisation caused by rennet could be shown clearly by several studies. Positive skin prick and challenge tests as well as specific IgE antibodies have been described, thus suggesting an immunological mechanism.

Ever-changing exposure to contact allergens, partly due to statutory directives (e.g. nickel, chromate, methyldibromo glutaronitrile) or recommendations from industrial associations (e.g. hydroxyisohexyl 3-cyclohexene carboxaldehyde), requires on-going epidemiologic surveillance of contact allergy. In this paper, the current state with special focus in fragrances and preservatives is described on the basis of data of the Information Network of Departments of Dermatology (IVDK) of the year 2010. In 2010, 12,574 patients were patch tested in the dermatology departments belonging to the IVDK. Nickel is still the most frequent contact allergen. However the continuously improved EU nickel directive already has some beneficial effect; sensitization frequency in young women is dropping. In Germany, chromate-reduced cement has been in use now for several years, leading to a decline in chromate sensitization in brick-layers. Two fragrance mixes are part of the German baseline series; they are still relevant. The most important fragrances in these mixes still are oak moss absolute and hydroxyisohexyl 3-cyclohexene carboxaldehyde. However, in relation to these leading allergens, sensitization frequency to other fragrances contained in the mixes seems to be increasing. Among the preservatives, MCI/MI has not lost its importance as contact allergen, in contrast to MDBGN. Sources of MCI/MI sensitization obviously are increasingly found in occupational context. Methylisothiazolinone is a significant allergen in occupational settings, and less frequently in body care products.

Preservatives are well-known and important contact allergens.To examine the frequency of sensitization to preservatives, including time trends.Retrospective analysis of data on patch testing of preservatives contained in the standard series and special series collected by the IVDK during 1996-2009.Some 120,000 and 80,000 patients were tested with the baseline and the preservative series, respectively. Sensitization frequencies of the standard series allergens all ranged above 1%: methyldibromoglutaronitrile (MDBGN) 2·36-4·5%, methy(chloro)isothiazolinone (MCI/MI) 2·22%, formaldehyde 1·54%, paraben mix 1·33% and Bronopol® 1·25%. Regarding the special preservative series, 1·54% reacted positive to methylisothiazolinone (MI), and1% to the other preservatives. Concomitant reactions to formaldehyde in formaldehyde releasers ranged from 15% to almost 50%, and 67% of MI positives reacted to MCI/MI. As indicated by the MOAHLFA index, sensitization to MI, iodopropynylbutyl carbamate (IPBC) and quaternium 15 was associated more often with occupational dermatitis, whereas sensitization to imidazolidinyl urea and diazolidinyl urea was associated with face dermatitis, indicating cosmetic exposure. Epidemiologically relevant decreases (10%) were seen in chloroacetamide, benzyl alcohol and MDBGN. Epidemiologically relevant increases were noted in IPBC, sodium benzoate and MI.Preservatives are still important contact allergens. The introduction of new preservatives should consider the specific characteristics of occupational and of nonoccupational (cosmetic, household) exposure, and preventive measures should aim equally at both areas.

A broad spectrum of various substances may cause occupational allergic contact dermatitis. Often, it is difficult to identify potentially or truly relevant allergens at the workplace. Therefore, the consulting physician must have a comprehensive knowledge of possible allergens in different occupations to perform specific diagnostics and to initiate efficient secondary prevention by allergen avoidance. In this review, we give some practically relevant general comments on patch testing in occupational dermatitis, followed by a discussion of important occupational allergens in those occupational groups most frequently affected by occupational dermatitis. Finally, recommendations on which allergens should be tested in the respective occupational groups are given or reported from the literature.

para-Phenylenediamine (PPD) is an important contact allergen and primarily used in hair dyeing.To quantify cases of contact allergy (CA) to PPD attributed to sources of exposure.Patients with PPD CA, diagnosed by the Information Network of Departments of Dermatology (IVDK; n = 3307 of 83 030 patients tested), were divided into five subgroups of exposure. Demographic variables and pattern of concomitant reactions were used to characterize the subgroups further. The impact of individual factors on the risk of PPD CA was examined with a logistic regression analysis. Clinical epidemiology and drug utilization research (CE-DUR) methods were employed to estimate the 10-year prevalence of PPD CA in the general population.The 4% prevalence of PPD CA in patients was extrapolated to a prevalence of 0.96% in the general population. The defined profiles were found to 'explain' the following percentages of PPD CA: (i) hair dyeing in clients 22% (0.2% of the general population); (ii) different occupational exposures, namely hair dyeing by hairdressers, paint- and rubber-associated exposures 23% (0.22% of the general population); (iii) clothing/shoes 12% (0.12% of the general population). A probable causal exposure to PPD could not be identified in about 44% of patients with PPD CA.In more than 50% of cases of PPD CA, a (very) probable causal exposure was identified. In the large remainder (44%) this was not possible. 'Historical' CA without current relevance and active sensitization through patch testing (a further important exposure to PPD) must be considered in these patients.

The selection of the most important contact allergens is subject to a continuous change. Several factors may influence the sensitization rates and thus the decision, which substances to include in the standard series of the most frequent allergens. The Information Network of Departments of Dermatology adds substances of interest for a certain time period to the standard series in order to evaluate parameters such as sensitization rate, grade of reaction, and clinical relevance of positive reactions. In 6 testing periods starting in 1996, 13 test substances were evaluated. Due to the results, propolis, compositae mix, and bufexamac were included in the standard series in 1999, while lyral was added in 2002. Sorbitansesquioleat, dispers blue mix, and iodopropynyl butylcarbamate are under further discussion. Substances such as glutaraldehyde and p-aminoazobenzole should be tested in certain risk groups only, whereas the steroids budesonide and tixocortol should be tested when clinically suspected.

In the 1960s an increasing number of occupational allergies in the detergent industry against the proteolytic enzyme Subtilisin were observed. In this context the high sensitization potential of enzyme dusts attracted attention. The present evaluation of literature data confirms that this is also true for cellulases. These enzymes--mostly of fungal origin--are frequently used in biotechnology. Several cases of specific airway sensitization caused by cellulases are verified by a number of studies. As symptoms, results of skin prick tests, detection of specific IgE-antibodies and results of specific bronchoprovocation tests are consistent, an immunologic mechanism seems to be confirmed.

In the early 1990s, the prevalence of nickel contact allergy was high-almost 20% on a population level, and some 40% in contact dermatitis patients. Around that time, nickel exposure was starting to be regulated.Descriptive and bivariate analyses of patch test results of all patients tested with nickel sulfate (5% pet.) in the departments joining the Network of Departments of Dermatology (IVDK) 1992-2001 (n=82,991, women: 52,709; men: 30,282). The annual frequency of sensitization to nickel was analyzed in women and men in four age subgroups (31/31 to44/44 to 58= or58).In young women less than 31 (n=13.909) the prevalence of contact allergy to nickel decreased significantly from 36.7% in 1992 to 25.8% in 2001. In young men in the same age group (n=7087), the prevalence dropped from 8.9% in 1992 to 5.2% in 2001.The observed decline indicates that measures to limit the release of nickel from costume jewelry helped reduce the prevalence of nickel allergy. In general term, allergen elimination or reduction is an effective primary prevention strategy which does not depend on individual behavior modifications.

Between 1995 and 1999, 1986 patients were tested in the 31 participating centres of the Information Network of Departments of Dermatology (IVDK), all of them members of the German Contact Dermatitis Research Group, with a textile dyes series containing Disperse Blue (DB) 106 and 124, and since 1997 also with a mix of both. 86 patients (4.3%) reacted positively to DB 106 and/or DB 124; with good concordance between the 2 allergens (Cohen's weighted kappa 0.72), and the single allergens and the mix (kappa=0.75 in both cases), which had been tested in parallel in 969 and 975 patients, respectively. In contrast, concordance between DB 106/124 and p-phenylenediamine and p-aminoazobenzene, respectively, was poor. Some 70% of positive reactions to DB 106/124 had current clinical relevance. Furthermore, a significant increase in the proportion of DB 106/124-positive patients among those tested was found from 1995 to 1999. Hence, DB 106/124 are important allergens deserving close monitoring. The use of a mix of DB 106 and DB 124 seems justified in view of the close chemical similarity of both compounds. If possible, the presence of the allergen(s) in individual textiles considered causative should be checked by thin layer or column chromatography.

Raisons du developpement du beton projete dans la construction de tunnel a Munich: flexibilite des sections transversales variant durant les travaux d'excavation comparee au percement au bouclier; adaptabilite aux divers sols et diverses conditions d'eau souterraine; possibilite d'application de mesures auxiliaires durant l'excavation (congelation, coulis d'injection, drainage); economie de la methode