A lung disorder characterized by attacks of breathing difficulty , wheezing , prolonged exhalation, and cough , which is caused by various agents found in the work place (see also bronchial asthma ). These symptoms are usually due to spasms of the muscles lining the airways, which cause them to narrow excessively.

Alternative Names

Asthma - occupational exposure; Byssinosis - work-aggravated asthma; Irritant-induced reactive airways disease

Causes, incidence, and risk factors

There are many agents in the workplace which can cause occupational asthma. Most commonly, these include protein molecules (wood dusts, grain dusts, animal danders, fungal substances) or other chemicals (especially di-isocyanates). Though the actual rate of occurrence of occupational asthma is unknown, it is suspected to cause between 2 and 20 percent of all cases of asthma in industrialized nations. Workers in the following occupations are at higher risk: plastics workers, metal workers, bakers, millers, farmers, grain elevator workers, laboratory workers, woodworkers, drug manufacturers, and detergent manufacturers.

Signs and tests

The history reveals a pattern of worsening symptoms associated with exposure to a specific agent or workplace environment. Making the association with the correct allergen can be very difficult. Wheezing may be heard when listening to the chest with a stethoscope ( auscultation ). Tests used in the diagnosis of occupational asthma may include:

Treatment

The objective of treatment is to limit exposure to the allergen and improve symptoms with bronchodilator therapy. In some instances, symptoms may persist despite removal of the source of exposure. Medications include hand-held inhalers or nebulizers to deliver bronchodilators. Other therapies for bronchial asthma may be added in more severe cases.

Support groups

The stress related to illness can often be helped by joining a support group where members share common experiences and problems. See asthma and allergy - support group .

Expectations (prognosis)

The outcome for people with asthma in general is good, but symptoms may persist for years after workplace exposure has been eliminated.

Complications

Complications include continued asthma symptoms after removal from the source of exposure.

Calling your health care provider

Call your health care provider if signs of occupational asthma develop. Call your health care provider if you have occupational asthma and signs of respiratory infection, or if other new symptoms, develop.

Prevention

Once the cause is determined, avoid further exposure to it.