Time course of onset of sensitization to common and occupational inhalants in apprentices

Career Advice for Young Allergy Patients

BACKGROUND

One-third of all young persons entering the work force have a history of atopic disease. Occupationally induced allergy and asthma generally arise in the first few months on the job, while pre-existing symptoms tend to worsen. Young persons with a history of an atopic disease should receive evidence-based advice before choosing a career.

METHODS

We systematically searched PubMed for cohort studies investigating the new onset of asthma, rhinitis, or hand eczema among job trainees from before the start of training and onward into the first few years on the job. The search revealed 514 articles; we read their abstracts and selected 85 full-text articles for further analysis. 24 of these met the inclusion criteria.

RESULTS

According to present evidence, atopy and a history of allergic disease (allergic rhinitis, atopic dermatitis) are the main risk factors for occupationally induced disease. The predictive value of a personal history of allergic diseases for the later development of an occupationally induced disease varies from 9% to 64% in the studies we analyzed. It follows that only young people with severe asthma or severe atopic eczema should be advised against choosing a job that is associated with a high risk of allergy, e.g., hairdressing or working with laboratory animals. Young people with a history of other atopic diseases should be counseled about their individual risk profile.

CONCLUSION

In view of the relatively poor predictive value of pre-existing atopic disease, secondary prevention is particularly important. This includes frequent medical follow-up of the course of symptoms over the first few years on the job. If sensitization or allergic symptoms arise, it should be carefully considered whether exposure reduction will enable the apprentice to stay on the job.

Occupational airborne exposure, specific sensitization and the atopic status: evidence of a complex interrelationship

Background

We have investigated the relationship between atopic status and long-term occupational exposure to latex proteins or methyl diethyl diisocyanate (MDI) as high and low molecular weight asthma-inducing agents, respectively.

Methods

This study is based on retrospective analyses of two groups of symptomatic outpatients: 184 healthcare workers with latex exposure and 156 workers with isocyanate (MDI) exposure. We analysed atopic and non-atopic subgroups according to exposure duration and the frequencies of specific sensitization.

Results

45% of the healthcare subgroup specifically sensitized to latex were atopic, whereas in the non-sensitized healthcare subgroup only 26% were atopic. On the other hand, subjects specifically sensitized to MDI were rarely atopic (only 15%), whereas in the subgroup non-sensitized to MDI atopy was present in 38%. After prolonged durations of exposure, the proportion of atopics was further elevated in most healthcare subgroups but it decreased in the MDI-exposed subjects.

Conclusions

We hypothesize that latex proteins as sensitizing agents might promote the development of atopy, whereas exposure to the low molecular weight MDI might inhibit the atopic status.

EAACI position paper: prevention of work-related respiratory allergies among pre-apprentices or apprentices and young workers

Apprenticeship is a period of increased risk of developing work-related respiratory allergic diseases. There is a need for documents to provide appropriate professional advice to young adults aiming to reduce unsuitable job choices and prevent impairment from their careers. The present document is the result of a consensus reached by a panel of experts from European and non-European countries addressed to allergologists, pneumologists, occupational physicians, primary care physicians, and other specialists interested in this field, which aims to reduce work-related respiratory allergies (rhinoconjunctivitis and asthma) among allergic or nonallergic apprentices and other young adults entering the workforce. The main objective of the document is to issue consensus suggestions for good clinical practice based on existing scientific evidence and the expertise of a panel of physicians.

New sensitization to house dust mites in cefteram-induced occupational asthma: a case report

Occupational asthma (OA) can improve after cessation of exposure; however, some patients suffer from persistence or aggravation of their asthmatic symptoms. Here we report a case of a new sensitization to house dust mites during the follow-up period in a 37-year-old female patient with OA induced by cefteram pivoxil powder (cefteram powder). She was previously diagnosed with OA caused by inhalation of cefteram powder. Consequently, she left her job and had been well for 9 subsequent years. She began to experience aggravation of her rhinitis and asthmatic symptoms again several months prior to presentation. Her skin-prick test results had converted to strongly positive responses to two types of house dust mites. The serum levels of eosinophil cationic protein (ECP) and the total and specific immunoglobulin (Ig)E levels against the two types of house dust mites were elevated. An inhalation challenge test with Dermatophagoides farinae was performed, and significant bronchoconstriction (21.1% reduction in the forced expiratory volume in the first second) with asthma symptoms was observed at 10 minutes. To our knowledge, this is the first case demonstrating a new sensitization to house dust mites in a patient with OA caused by cefteram powder. Regular monitoring, including skin-prick tests and measurement of specific serum IgE/ECP levels, may help to screen potential cases.

[Rhinitis and asthma related to cotton dust exposure in apprentices in the clothing industry]

OBJECTIVE

Respiratory allergies are the most common occupational diseases in the world. The aim of this study was to determine the prevalence of rhinitis and asthma among apprentices exposed to cotton dust in the clothing industry and to describe their epidemiologic and clinical profiles.

SUBJECTS AND METHODS

We carried out a descriptive study of 600 apprentices in a textile and clothing vocational training centre in the Monastir area. The investigation comprised a questionnaire exploring risk factors and symptoms appearing during their training. Subjects who developed allergic respiratory symptoms at the work-place underwent a clinical examination, rhinomanometry and investigation of their allergic status and respiratory function.

RESULTS

One hundred twenty apprentices (20%) developed allergic respiratory reactions due to exposure to textile dust (exclusively cotton) during their training, with a positive withdrawal-re-exposure test. Conjunctivitis (14.3%) and rhinitis (8.5%) were the most frequent allergic symptoms. Twenty eight apprentices (4.6%) presented symptoms of asthma. Rhinitis was associated with asthma in 45% of cases. Two cases of asthma were diagnosed clinically at the work-place following their exposure to textile dust. The prick test performed in 120 symptomatic apprentices was positive in 41.6% of cases. There was sensitization to pollens in 29 cases and to dermatophagoides in 13 cases. Cotton and wool allergy was noted in two cases. Allergic symptoms developing during the training were significantly more frequent in the atopic group, and they varied according to the intensity of textile dust exposure.

CONCLUSION

In the textile and clothing industry the frequency of respiratory disorders caused by allergens remains high, especially in atopic apprentices who constitute a population at high risk.

EAACI position paper on occupational rhinitis

The present document is the result of a consensus reached by a panel of experts from European and non-European countries on Occupational Rhinitis (OR), a disease of emerging relevance which has received little attention in comparison to occupational asthma. The document covers the main items of OR including epidemiology, diagnosis, management, socio-economic impact, preventive strategies and medicolegal issues. An operational definition and classification of OR tailored on that of occupational asthma, as well as a diagnostic algorithm based on steps allowing for different levels of diagnostic evidence are proposed. The needs for future research are pointed out. Key messages are issued for each item.

Outcomes in occupational asthma caused by reactive dye after long-term avoidance

BACKGROUND

Reactive dye (RD) is known to be a causative agent of occupational asthma (OA). However, to date, no report has been issued concerning the long-term outcomes of RD-induced OA.

OBJECTIVES

We sought to evaluate the long-term outcomes in cases of OA caused by RD.

METHODS

A total of 11 OA patients confirmed by RD bronchial challenge were enrolled in this study. First and second follow-up examinations were conducted at 4.3+/-2.3 and 13.7+/-2.3 years (means+/-SD) after the initial examinations, respectively. Skin prick test with RD and 11 common inhalant allergens, pulmonary function test, methacholine bronchial provocation testing, symptom and medication scores were determined at each visit. In addition, inflammatory cells in induced sputum were measured at the second follow-up examinations.

RESULTS

Reduced lung function at initial examinations did not recover at the first and second examinations despite cessation of exposure and proper pharmacological treatment. In addition, asthma severity (as determined by symptom and medication scores) and non-specific airway hyper-responsiveness to methacholine also did not improve. However, skin reactivity to RD almost disappeared at the second examinations. Interestingly, four of the six patients who showed negative skin responses to all 11 common inhalant allergens at initial examinations were found to be atopic at the second examinations. Moreover, in terms of airway inflammation, seven of the 11 patients showed eosinophilia in induced sputum (> or =3%) at the second examinations despite having been on high-dose inhaled corticosteroid medication.

CONCLUSION

The present study demonstrates that reduced lung function and asthmatic symptoms persist in RD-induced OA even after long-term exposure avoidance.

Inverse association between rural environment in infancy and sensitization to rodents in adulthood

BACKGROUND

It is not known whether early childhood exposure to hygiene hypothesis factors modifies the risk of sensitization to aeroallergens among adults. Studying adults exposed to allergens in the workplace may help determine whether childhood exposures confer lasting protection against sensitization.

OBJECTIVE

To determine whether early life exposures influence the prevalence of sensitization to allergens in adulthood.

METHODS

Sensitization to rodents was determined by skin testing in a cross-sectional study among university employees with and without occupational exposure to laboratory animals. Demographic information was obtained by questionnaire.

RESULTS

Of 137 employees, 8% of workers without occupational exposure to laboratory animals and 24% of those with such exposure were sensitized to rodents (P = .007). None of 32 study participants who lived in a rural environment during their first year of life were rodent sensitized vs 18% of those who lived in other settings (P < .01). Rural setting in infancy was also associated with a decreased prevalence of sensitization to outdoor allergens (odds ratio [OR], 0.36; 95% confidence interval [CI], 0.14-0.95). After adjusting for multiple confounders, sensitization to rodents remained rare among individuals who lived in a rural setting during infancy (OR, <0.15). Rodent sensitization was more prevalent among those with higher educational attainment (OR, 9.50; 95% CI, 1.10-82.02) and those sensitized to indoor allergens (OR, 6.22; 95% CI, 1.42-27.24). Sensitization to rodents was not significantly associated with having older siblings or sensitization to outdoor allergens.

CONCLUSIONS

Living in a rural setting during the first year of life is associated with protection from sensitization to rodent allergens in the workplace decades later.

Airway hyperresponsiveness and risk of chest symptoms in an occupational model

BACKGROUND

The clinical outcome of asymptomatic airway hyperresponsiveness (AHR) remains unclear. A study was undertaken to evaluate the incidence of respiratory symptoms in a cohort of asymptomatic subjects with AHR at baseline.

METHODS

A 3 year prospective study involving methacholine challenge tests and serially administered questionnaires was undertaken in 769 apprentices exposed to high molecular weight allergens. Analyses were performed on 428 initially asymptomatic subjects.

RESULTS

Thirty eight subjects (8.9%) were airway hyperresponsive (PC(20) < or =8 mg/ml) and asymptomatic at the start of the study. Forty four apprentices (10.3%) developed two or more respiratory symptoms unrelated to work, 13 (34.2%) in the AHR group and 31 (7.9%) in the non-AHR group (risk ratio (RR) 7.88 (95% CI 2.53 to 24.55) among subjects with AHR). The RR of developing two or more respiratory symptoms increased as the degree of PC(20) decreased with a significant trend (p<0.001). In a multivariate analysis, AHR (RR 8.33, 95% CI 2.65 to 26.16) and self-reported rhinitis on exposure to pollen through an interaction with a family history of asthma (RR 6.3, 95% CI 1.29 to 31.89) were associated with the incidence of two or more respiratory symptoms; atopy was not a significant covariate.

CONCLUSION

AHR in asymptomatic subjects is an important determinant for the development of respiratory symptoms outside the workplace among apprentices exposed to high molecular weight allergens in their training environment.

Induction of asthma and the environment: what we know and need to know

The prevalence of asthma has increased dramatically over the last 25 years in the United States and in other nations as a result of ill-defined changes in living conditions in modern society. On 18 and 19 October 2004 the U.S. Environmental Protection Agency and the National Institute of Environmental Health Sciences sponsored the workshop "Environmental Influences on the Induction and Incidence of Asthma" to review current scientific evidence with respect to factors that may contribute to the induction of asthma. Participants addressed two broad questions: a) What does the science suggest that regulatory and public health agencies could do now to reduce the incidence of asthma? and b) What research is needed to improve our understanding of the factors that contribute to the induction of asthma and our ability to manage this problem? In this article (one of four articles resulting from the workshop), we briefly characterize asthma and its public health and economic impacts, and intervention strategies that have been successfully used to prevent induction of asthma in the workplace. We conclude with the findings of seven working groups that focus on ambient air, indoor pollutants (biologics), occupational exposures, early life stages, older adults, intrinsic susceptibility, and lifestyle. These groups found strong scientific support for public health efforts to limit in utero and postnatal exposure to cigarette smoke. However, with respect to other potential types of interventions, participants noted many scientific questions, which are summarized in this article. Research to address these questions could have a significant public health and economic impact that would be well worth the investment.

A brief targeted review of susceptibility factors, environmental exposures, asthma incidence, and recommendations for future asthma incidence research

Relative to research on effects of environmental exposures on exacerbation of existing asthma, little research on incident asthma and environmental exposures has been conducted. However, this research is needed to better devise strategies for the prevention of asthma. The U.S. Environmental Protection Agency (EPA) and National Institute of Environmental Health Sciences held a conference in October 2004 to collaboratively discuss a future research agenda in this area. The first three articles in this mini-monograph summarize the discussion on potential putative environmental exposure; they include an overview of asthma and conclusions of the workshop participants with respect to public health actions that could currently be applied to the problem and research needs to better understand and control the induction and incidence of asthma, the potential role of indoor/outdoor air pollutants in the induction of asthma), and biologics in the induction of asthma. Susceptibility is a key concept in the U.S. EPA "Asthma Research Strategy" document and is associated with the U.S. EPA framework of protecting vulnerable populations from potentially harmful environmental exposures. Genetics, age, and lifestyle (obesity, diet) are major susceptibility factors in the induction of asthma and can interact with environmental exposures either synergistically or antagonistically. Therefore, in this fourth and last article we consider a number of "susceptibility factors" that potentially influence the asthmatic response to environmental exposures and propose a framework for developing research hypotheses regarding the effects of environmental exposures on asthma incidence and induction.

Sensitisation to mites in laboratory animal workers with rhinitis

AIMS

To determine the frequency of sensitisation to mites among rhinitic laboratory animal workers and to clarify whether sensitisation could be occupational.

METHODS

Skin prick tests (SPT) were performed in 40 subjects who were working with laboratory animals in Kuopio University research units and who had been referred to Kuopio University Hospital for work related rhinitis. The SPT panel consisted of three storage mites, two house dust mites, 11 other common environmental airborne allergens, latex, and 2-4 individually relevant laboratory animals. To determine signs of mites in animal facilities, guanine was determined in 22 dust samples taken from feedstuffs or bedding material used for laboratory animals and from rooms where these materials were stored and handled.

RESULTS

Positive SPT results were found in 35 out of 40 workers: in 14 for storage mites, four for house dust mites, 25 for other common aeroallergens, as well as positive reactions to laboratory animals in 19 individuals. The guanine test was positive, indicating the presence of mite derived material in 21 out of 22 dust samples.

CONCLUSIONS

This study suggests that subjects who are occupationally exposed to laboratory animals are also exposed to mite derived allergens. Sensitisation to mites is common and may be work related.

Occupational asthma

Substantial epidemiologic and clinical evidence indicates that agents inhaled at work can induce asthma. In industrialized countries, occupational factors have been implicated in 9 to 15% of all cases of adult asthma. Work-related asthma includes (1) immunologic occupational asthma (OA), characterized by a latency period before the onset of symptoms; (2) nonimmunologic OA, which occurs after single or multiple exposures to high concentrations of irritant materials; (3) work-aggravated asthma, which is preexisting or concurrent asthma exacerbated by workplace exposures; and (4) variant syndromes. Assessment of the work environment has improved, making it possible to measure concentrations of several high- and low-molecular-weight agents in the workplace. The identification of host factors, polymorphisms, and candidate genes associated with OA is in progress and may improve our understanding of mechanisms involved in OA. A reliable diagnosis of OA should be confirmed by objective testing early after its onset. Removal of the worker from exposure to the causal agent and treatment with inhaled glucocorticoids lead to a better outcome. Finally, strategies for preventing OA should be implemented and their cost-effectiveness examined.

Airway Inflammation after Cessation of Exposure to Agents Causing Occupational Asthma

Subjects with occupational asthma (OA) generally present asthma symptoms and airway hyperresponsiveness after cessation of exposure. We hypothesized that they are also left with airway inflammation. We assessed 133 subjects with OA at a mean interval of 8.7 years (0.5-20.8 years) after cessation of exposure by questionnaire, airway caliber, and responsiveness to methacholine. Satisfactory samples of induced sputum were obtained from 98 subjects. We defined three groups of subjects: (1) cured: normalization of the concentration of methacholine provoking a 20% decrease in FEV1 (PC20), (2) improved: increase in PC20 by 3.2-fold or more but PC20 still abnormal, and (3) not improved: no significant change in PC20. In all, 9/28 subjects (32.1%) with no improvement versus 6/56 (10.7%) subjects with partial and complete improvements had sputum eosinophils equal to or greater than 2% and 11/28 (39.3%) subjects versus 11/56 (19.6%) subjects showed sputum neutrophils equal to or greater than 61%. Levels of interleukin-8 and of the neutrophil-derived myeloperoxidase were significantly more elevated in sputum of subjects with no improvement. Those in the cured or improved groups had a significantly longer time lapse since diagnosis and a higher PC20 at the time of diagnosis. We conclude that failure to improve after cessation of exposure to an agent causing OA is associated with airway inflammation at follow-up.