Approximately 15 percent of adults with asthma experience occupational asthma. Occupational asthma is a type of asthma caused by exposure to inhaled irritants in the workplace. Occupational asthma is often a reversible condition, which means the symptoms may disappear when the irritants that caused the asthma are avoided. However, permanent damage can result if the person experiences prolonged exposure. Examples of workplace irritants include:
Occupational asthma often begins with a cough or other asthma symptoms, such as wheezing, shortness of breath, runny nose, nasal congestion, eye irritation, and chest tightness, that may occur during exposure to the irritant(s) at work. The cause can be allergic or nonallergic in nature. Sometimes, occupational asthma symptoms do not appear until several hours after the exposure, even while at home after work. At the onset of the disease, symptoms may subside during weekends and vacations, but exposure to an occupational irritant can cause asthma within 24 hours. However, during later stages of occupational asthma, asthma symptoms may begin occurring during exposure to other, more common asthma triggers, such as smoke, dust, and temperature changes.
Although new substances are developed every day that may cause occupational asthma, some known airborne irritants in the workplace include:
|Irritant||Examples||Type of occupations/
environments at risk
|Chemical dusts and vapors||Isocyanates, trimellitic anhydride, phthalic anhydride||Manufacturers of foam mattresses and upholstery, insulation, packaging materials, plasticizers, and polyurethane paint|
|Animal substances||Bacterial dusts, dander, hair, mites, protein dusts, small insects||Farmers, animal handlers, kennel workers, jockeys, and veterinarians|
|Organic dusts||Cereals, coffee, flour, grains, tea||Millers, bakers, and other food processors|
|Cotton, flax, and hemp dust||Dusts from cotton and textile industry||Cotton and textile workers|
|Metals||Chromium, nickel sulfate, platinum, soldering fumes||Manufacturers of metals and refineries|
Avoidance of triggers is the best prevention against asthma. If occupational asthma symptoms do occur, you may need to change jobs to avoid exposure. However, certain steps taken in the workplace can help reduce the risk of occupational asthma:
The degree to which cigarette smoking contributes to occupational asthma is not known, but smokers are more likely than nonsmokers to develop lung problems in general.
Diagnosis of occupational asthma usually includes a detailed medical history and doctor's examination to establish the relationship of the symptoms to exposure at work. Other diagnostic procedures may include pulmonary function tests before and after work to detect narrowing of the airways, blood and sputum laboratory tests, and a chest X-ray to rule out other lung diseases.
Treatment for occupational asthma usually includes avoiding the substance that triggers the asthma attack or symptoms. Persons with occupational asthma should also avoid inhaling gases, such as chlorine, or nitrogen dioxide, and sulfur dioxide, as these substances can make asthma symptoms more severe. Other treatment may include medications to control the asthma. If the occupational asthma is advanced, treatment may also include:
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