Tobacco Worker's Lung

Updated: Jun 03, 2014
  • Author: Roger B Olade, MD, MPH; Chief Editor: Ryland P Byrd, Jr, MD  more...
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Overview

Background

Tobacco worker's lung (TWL) is one disease in the group of parenchymal lung diseases categorized as hypersensitivity pneumonitis (United States) or extrinsic allergic alveolitis (Britain). [1] This disease entity is caused by inhalation of tobacco molds and is encountered in persons who work in tobacco fields and cigarette manufacturing plants.

Increased humidity plays a major role in favoring mold growth. [2] The clinical features and natural history are akin to hypersensitivity pneumonitis of other causes.

It usually involves inhalation of an antigen, particularly organic ones. This leads to an exaggerated immune response, which produces a complex clinical presentation within the pulmonary parenchyma.

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Pathophysiology

Immune mediation plays a major pathogenetic role in tobacco worker’s lung. Serum antibodies are present in most patients with tobacco worker’s lung, but a lack of correlation between the presence of serum antibodies and pulmonary symptoms has been noted.

In tobacco worker’s lung, the culprit antigen is the Aspergillus species, with a source in tobacco molds. The antigens induce injury by causing macrophages and polymorphonuclear leukocytes to produce substances such as proteolytic enzymes and reactive oxygen compounds. These further lead to synthesis and release of interleukin (IL)-1, tumor necrosis factor (TNF)-alpha, and IL-6 from macrophages and lymphokines from lymphocytes, which result in pulmonary inflammation. Lung biopsies in patients with long-term exposure usually demonstrate chronic interstitial inflammation and poorly formed nonnecrotizing granulomas. [3]

In addition, smoking can potentiate the effects of tobacco dust. [4]

Recent studies have shown that there might be a genetic predisposition to hypersensitivity pneumonitis, postulated to play a major role in determining an individual's risk of disease. It is likely that the immunologic abnormalities that underlie hypersensitivity pneumonitis reflect the interplay of multiple genes involved in the immune response. Genetic involvement can be extrapolated to apply to risk for tobacco worker's lung. [5]

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Epidemiology

Frequency

Data are not available.

Mortality/Morbidity

Because of the excellent prognosis, little documented evidence of long-term illness or death from tobacco worker’s lung exists.

Sex

Although no documented evidence indicates a sex predilection, tobacco worker’s lung is more common in males, probably because most tobacco workers are men. However, recent data show that female tobacco workers are more prone to respiratory symptoms and lung impairments despite working in an environment with lower levels of pollution. [4]

Age

Tobacco worker’s lung occurs in adults of working age but not in children or retired people.

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