Occupational Asthma
Alternative Names
Asthma - occupational exposure; Irritant-induced reactive airways disease
Definition
Occupational asthma is a lung disorder in which substances found in the workplace cause the airways of the lungs to swell and narrow. This leads to attacks of wheezing, shortness of breath, chest tightness, and coughing.
Causes
Asthma is caused by inflammation (swelling) in the airways of the lungs. When an asthma attack occurs, the lining of the air passages swells and the muscles surrounding the airways become tight. This reduces the amount of air that can pass by.
In persons who have sensitive airways, asthma symptoms can be triggered by breathing in substances called triggers.
Many substances in the workplace can trigger asthma symptoms, leading to occupational asthma. The most common triggers are wood dust, grain dust, animal dander, fungi, or chemicals.
The following workers are at higher risk:
- Bakers
- Detergent manufacturers
- Drug manufacturers
- Farmers
- Grain elevator workers
- Laboratory workers (especially those working with laboratory animals)
- Metal workers
- Millers
- Plastics workers
- Woodworkers
Symptoms
Symptoms are usually due to narrowing of the airways and tightening spasms of the muscles lining the airways. This reduces the amount of air that can pass through and it can lead to wheezing sounds.
Symptoms usually occur shortly after you are exposed to the substance. They often improve or go away when you leave work. Some people may not have symptoms until 12 or more hours after being exposed to the allergen.
Symptoms usually get worse toward the end of the work week and may go away on weekends or vacations.
Symptoms include:
- Coughing
- Tight feeling in the chest
- Shortness of breath
- Wheezing
Exams and Tests
The health care provider will perform a physical exam and ask about your medical history. Your symptoms may have a pattern of getting worse with a certain workplace environment or substance.
The health care provider will listen to your lungs with a stethoscope to check for wheezing.
Tests may be ordered to confirm diagnosis:
- Blood tests to look for antibodies to the substance
- Bronchial provocation test (test measuring reaction to the suspected allergen)
- Chest x-ray
- Complete blood count
- Peak expiratory flow rate
- Pulmonary function tests
Treatment
Avoiding exposure to the substance that is causing your asthma is the best treatment.
Measures may include:
- Changing jobs (though this may be difficult to do)
- Moving to a different location at the work site where there is less exposure to the substance. This may help, but over time, even a very small amount of the substance can trigger an asthma attack.
- Using a respiratory device to protect or reduce your exposure may help.
Asthma medicines may help manage your symptoms.
Your doctor may prescribe:
- Asthma quick-relief medicines, called bronchodilators, to help relax the muscles of your airways.
- Asthma control medicines that are taken every day to prevent symptoms.
Outlook (Prognosis)
Occupational asthma may keep getting worse if you continue to be exposed to the substance that is causing the problem, even if medicines improve your symptoms. You may need to change jobs.
Sometimes, symptoms may continue even when the substance is removed.
In general, the outcome for people with asthma is good. However, symptoms may continue for years after you are no longer exposed in the workplace.
When to Contact a Medical Professional
Call your health care provider if you have symptoms of asthma.
References
Chan-Yeung M, Malo JL. Asthma in the workplace and occupational asthma. In: Mason RJ, Broaddus VC, Martin TR, et al., eds. Murray & Nadel's Textbook of Respiratory Medicine. 5th ed. Philadelphia, Pa.: Elsevier Saunders; 2010:chap 64.
Cowl CT. Occupational asthma: review of assessment, treatment, and compensation. Chest. 2011;139:674-681.