Background Hypersensitivity pneumonitis (HP) is caused by a variety of antigens and low-molecular-weight chemicals, often through occupational exposure. Making a diagnosis of HP and identifying a cause are challenging. Cryptogenic cases are frequently reported, and missing or incomplete exposure histories can cause misclassification. Aims To provide an evidence-based compendium of sources of exposure and causes of HP for the clinician, through systematic review of medical literature. Methods Articles related to HP causative agents and occupational exposure were searched from the databases OVID Medline (1946 to October 2020) and EMBASE (1974 to October 2020). s and full texts of articles were screened by two reviewers. Data on causative antigens, occupational source of exposure and any associated eponymous name were extracted and grouped according to source of exposure. Results A total of 1790 articles were identified, from which 305 articles met the inclusion criteria. An additional 22 articles were identified from citation lists of the selected review articles. Sources of exposure identified for HP were sorted into 14 categories of work (agricultural, plant matter processing, wood, animal-related, foodstuff, food processing, metal processing, polymers, other manufacturing, chemicals, aerosolized water, service, waste and sewage and wind instruments). Conclusions This work is a comprehensive list of occupational causative agents and exposures causing HP. Cases are grouped by source of exposure, allowing an immediately accessible compendium of causes for use during occupational exposure assessment, which could also form the basis for a clinical questionnaire.

中文翻译：

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过敏性肺炎的职业原因：系统评价和纲要

背景 过敏性肺炎 (HP) 是由多种抗原和低分子量化学物质引起的，通常是通过职业暴露引起的。诊断 HP 并确定病因具有挑战性。经常报告隐源性病例，缺失或不完整的接触史可能导致错误分类。目的 通过对医学文献的系统评价，为临床医生提供基于证据的暴露源和 HP 原因的概要。方法 从 OVID Medline（1946 年至 2020 年 10 月）和 EMBASE（1974 年至 2020 年 10 月）数据库中检索与 HP 病原体和职业暴露相关的文章。s和文章全文由两位审稿人筛选。关于致病抗原的数据，提取职业接触源和任何相关的同名名称，并根据接触源进行分组。结果共识别出1790篇文章，其中305篇符合纳入标准。从所选评论文章的引用列表中确定了另外 22 篇文章。确定的 HP 接触源分为 14 类工作（农业、植物物质加工、木材、动物相关、食品、食品加工、金属加工、聚合物、其他制造、化学品、雾化水、服务、废物和污水以及管乐器）。结论 这项工作是导致 HP 的职业病原体和暴露的综合清单。病例按接触源分组，