Asthma on the Job
Did you know that your job could trigger allergies and asthma? Occupational asthma, defined as a lung disorder caused by inhaling fumes, gases, dust, or other potentially harmful substances while on the job, is the most prevalent work-related disease in developed countries. In fact, it is estimated that up to 15 percent of asthma cases in adults may have job-related factors. Occupational asthma also accounts for approximately 24.5 million missed workdays for adults annually in the United States.
Signs & Symptoms
Symptoms of occupational asthma may include wheezing, shortness of breath, chest tightness, cough, runny nose or nasal congestion, and eye irritation.
The disease may last for a lengthy period in workers, even if they are no longer exposed to the agents. Symptoms will usually worsen through the workweek, improve on the weekend, and reappear when an employee returns to the job. The length of occupational exposure that triggers asthma varies, and it can be months to years before symptoms occur. Occasionally, an accident at work involving high exposure to irritating fumes or dusts may cause asthma within 24 hours.
Early recognition and control of triggers is important in occupational-induced asthma because the longer employees are exposed, the less likely it is that they will completely overcome their asthma symptoms. If you experience any of the above symptoms, be sure to see your doctor for an evaluation.
If occupational asthma is not correctly diagnosed early, lung damage can occur and asthma symptoms may persist even after exposure has ceased.
Unfortunately, many workers with persistent asthma symptoms caused by substances at the workplace are incorrectly diagnosed as having bronchitis. If occupational asthma is not correctly diagnosed early, and the worker is not protected or removed from the exposure, lung damage can occur and asthma symptoms may persist even after exposure has ceased.
Occupational asthma may be caused by one of three mechanisms:
- Direct irritant effects
Irritants that provoke occupational asthma include hydrochloric acid, sulfur dioxide, and ammonia, which is found in the petroleum and chemical industries. Workers exposed to these substances will frequently begin wheezing and experiencing other asthma symptoms immediately after exposure to the irritant substances. This is an irritant reaction rather than an allergic reaction because it does not involve the immune system. Workers who already have asthma or some other respiratory disorder are particularly affected by this type of exposure.
- Allergy (long-term exposure)
Allergies play a role in many cases of occupational asthma. This type of asthma generally develops only after long-term exposure (months or years) to a work-related substance. This is because the body’s immune system needs time to develop allergic antibodies or other immune responses to a particular substance.
- Pharmacologic mechanisms
Inhalation of some substances in aerosol form can directly lead to the accumulation of naturally occurring chemicals in the body, such as histamine or acetylcholine within the lung, which can lead to asthma. For example, insecticides, used in agricultural work, can cause a buildup of acetylcholine, which causes airway muscles to contract and constrict.
With occupational asthma, symptoms of asthma may develop for the first time in a previously healthy worker, or childhood asthma that had previously cleared may recur due to new exposure. In many cases, a previous personal or family history of allergies will make a person more likely to develop occupational asthma. However, many individuals who have no such history still will develop asthma if exposed to conditions that trigger it. Additionally, workers who smoke are at greater risk for developing asthma after occupational exposures.
The incidence of occupational asthma varies by industry. Workers who are at risk for occupational asthma include workers who are routinely exposed to chemicals, including spray painting, insulation installation, and in manufacturing plastics, rubber, resin, and foam; people working with animals or with powdered natural rubber latex gloves; those in the detergent industry; adhesive handlers; food-processing workers; beauticians and hairdressers; janitors; textile workers; carpet makers; and healthcare professionals.
Once the cause of occupational asthma is identified, exposure to the triggers should be reduced. Work areas should be closely monitored so exposure to asthma-causing substances is kept to a minimum. Workers who are currently experiencing symptoms or who anticipate being exposed to agents that increase their risk of developing asthma should see their doctor for an evaluation and proper diagnosis. In some cases, pretreatment with specific medications to counteract the effects of workplace substances may be helpful. In other situations, however, complete avoidance is necessary.
Reducing exposure to occupational asthma triggers, receiving appropriate treatment, and practicing careful avoidance measures will improve your quality of life and help you feel relief from symptoms. If you have questions about treatments available for occupational asthma, be sure to ask your doctor.
Source: American Academy of Allergy, Asthma & Immunology, www.aaaai.org
This article was originally published in Coping® with Allergies & Asthma magazine, September/October 2009.