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Occupational Asthma & Workplace Asthma Triggers

Could Work Be Making You Sick?

By Anna Loengard, M.D.

Updated February 20, 2008

(LifeWire) - Occupational asthma occurs when a person develops asthma symptoms in response to an exposure to dust, fumes, gases or other irritants in the workplace that are known as workplace triggers. Occupational asthma, or OA for short, is becoming increasingly common.

The number of workers affected by OA varies by country and by industry. Approximately 10% of all asthma cases are now believed to have an occupational source.

Who Is at Risk for OA?

Many occupations put people at risk for OA. The main factor is exposure to inhaled irritants. Substances that commonly cause OA are spray paints, chlorine and isocyanate – a substance used in plastics and adhesives. More than 250 occupations have been found to cause OA.

People affected by OA range from chicken farmers to chemical plant workers to candy makers to healthcare workers, and everything in between.

How Does OA Develop?

OA is often the body's allergic response to a trigger substance, as is the case with many types of asthma. It is unclear exactly how allergy-induced asthma develops; however, it seems to involve the immune system.

When a substance, such as a chemical, animal dander or wood dust, is inhaled over time, the immune system in the airways triggers an antibody response. This response causes inflammation or swelling of the breathing tubes, constriction of the surrounding muscles and extra mucus production. The effects of these changes are asthma symptoms, such as difficulty in breathing, coughing, wheezing and chest tightness.

Asthma may also be triggered because the offending substance is a direct irritant to the airways. When this occurs, there is no antibody response, but the same symptoms occur and may be severe.

It is still a mystery why some people respond to a substance by developing asthma, whereas the majority of other people do not respond this way. Genetic factors or specific aspects of the immune cells probably play a part in the asthmatic response.

Therefore, it has been suggested that companies should screen applicants for positions where exposure to irritants are likely to be encountered. By screening for those who already have asthma or those with strong personal or family histories of allergies, the number of workers developing OA could be limited.

How Doctors Diagnose OA

Diagnosis of OA can be challenging. People vary in how fast they develop symptoms. Some workers may have an asthma attack immediately on exposure to the trigger substance, whereas others may not be affected for weeks, months or years.

It can also be hard to tell whether asthma symptoms are being caused by an exposure at work or at home. It is critical for a doctor to obtain complete information to understand exactly when the symptoms occur, when they began, when they go away, etc. Tracking your symptoms & triggers can help the doctor a great deal.

The suspicion for OA should be raised if the symptoms are worse during working hours and whether or not they improve when the person is away from the workplace.

Lung or pulmonary function tests can be done to test for OA; however, these tests may show normal results if there is no active disease when they are performed. Skin tests may also show evidence of allergies to work exposures. Also, blood tests may be used to detect a systemic allergic response.

If pulmonary function tests are normal, the doctor may order what is called a provocation test. This requires the patient to inhale a small amount of the irritant involved at the workplace. It is important that this test should only be performed in a specialized facility that is prepared to treat an extreme allergic reaction should one occur.

How OA Is Treated

The best treatment for OA is to stop the exposure to the irritant substance. Unfortunately, however, for many people this will not mean an immediate cure to their asthma. Some people have been found to have symptoms for years after the exposure has ended. It is important for anyone who may have OA to work closely with his or her doctor to avoid long-term disease and disability.

If removal or avoidance of the offending material is impossible, it is important to look into ways to minimize exposure. These measures can include better ventilation, fitting of a new mask or moving farther from the source.

If symptoms persist, asthma medications can be used. Inhaled steroids with a second inhaler for sudden attacks are usually prescribed for persistent symptoms. Smokers who develop OA may have worse symptoms of the disease and are also at risk for other lung diseases – such as emphysema – which leads to greater disability.

Social and Legal Implications of OA

It can be challenging to live with both the physical and emotional aspects of OA. Some people may believe that they must choose between their health and the financial security of their family. These people will risk continued exposure if they are not qualified for another line of work. It is important to speak with someone about these concerns – a social worker or even an asthma support group can help – to get ideas on how to safeguard both physical and financial well-being. Ask your doctor about sources of support and information.

The Occupational Safety and Health Administration (OSHA) regulations state that employers must provide a safe work environment. This includes providing adequate air quality, masks and respirators when working with very toxic material, including the training for how to properly use these devices. If you believe that your employer has been negligent, contact your local OSHA office.

Related Articles


American Academy of Allergy Asthma & Immunology. 5 Jan 1958. "Reducing Exposure Can Reduce Symptoms of Occupational Asthma." 17 Dec. 2007 <http://www.aaaai.org/media/news_releases/2006/01/010506.stm>

Mayo Clinic Staff. "Occupational Asthma." 24 May 2007. Mayo Foundation for Medical Education and Research. MayoClinic.com 17 Dec. 2007 <http://www.mayoclinic.com/health/occupational-asthma/DS00591/DSECTION=8>

Montanaro, Anthony. "Occupational Asthma." Immunology and Allergy Clinics of North America. (2001) 21(3):489-501. 17 Dec. 2007 <http://www.immunology.theclinics.com/article/PIIS088985610570223X/fulltext>

"OSH Answers: Diseases, Disorders & Injuries." 8 Feb. 2007. Canadian Centre for Occupational Health & Safety. 17 Dec. 2007 <http://www.ccohs.ca/oshanswers/diseases/asthma.html>

"Occupational Asthma." American Lung Association. March 2002. lungusa.org 17 Dec. 2007 <http://www.lungusa.org/site/pp.asp?c=dvLUK9O0E&b=22597>

"Public Education: Occupational Asthma." American College of Allergy, Asthma & Immunology. acaai.org 17 Dec. 2007 <http://www.acaai.org/public/advice/occAsth.htm>

"Respiratory Protection. - 1910.134." Regulations (Standards - 29 CFR). 24 Aug. 2006. U.S. Department of Labor, Occupational Safety & Health Administration. osha.gov 17 Dec. 2007 <http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=12716>

LifeWire, a part of The New York Times Company, provides original and syndicated online lifestyle content. Dr. Anna Loengard is a board certified, Harvard-trained internist, geriatrician and palliative medicine specialist, and an assistant clinical professor of geriatrics at the Mount Sinai School of Medicine in New York City.
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