What Triggers Occupational Asthma & What Is The Prognosis For It?

Occupational asthma appears when a person is exposed to certain substances in his workplace that either causes inflammation or irritation in the lungs. One of the characteristic features of this asthma is that it gets better when the patient is away from the exposure or workplace in the weekends or holidays. Its symptoms are similar to the usual signs of asthma i.e., shortness of breath, wheezing, tightness in the chest, and cough. It is diagnosed with the help of a lung function test, skin prick test, chest X-ray, blood tests, and others. It can be prevented by changing the occupation and absolute avoidance of exposure.

What Triggers Occupational Asthma?

There are many substances that trigger occupational asthma. There are more than 250 workplace substances that are identified as possible causes of occupational asthma. These substances are listed below-

Animal Substances- substances like specific proteins found in dander, hair, fur, saliva, scales, and body waste products of animals.

Plant Substances- some plant extract proteins found in natural rubber latex, wheat, flax, flour, cotton, cereals, hemp, rye, and papain — a digestive enzyme derived from papaya can also be a causative agent.

Chemicals- certain chemicals are utilized in the preparation of paints, varnishes, laminates, adhesives, and soldering resin. Some chemicals used to make insulation, foam mattresses, packaging materials, and upholstery can induce this asthma.

Enzymes – specific enzymes used in the preparation of detergents and flour conditioners can trigger this asthma.

Metals- exposure to metals, particularly platinum, chromium, and nickel sulfate, can cause this asthma.

Respiratory Irritants- exposure to particular gases such as chlorine gas, sulfur dioxide, and smoke can irritate the respiratory tract.(2)

Asthma symptoms begin when the lungs get irritated or inflamed. Inflammation induces a sequence of reactions in the respiratory tract that reduces the diameter of the airways, resulting in difficulty in breathing. In the case of occupational asthma, lung inflammation leads to an allergic response to a particular substance. It usually takes some time to develop. In case of exposure to fumes from lung irritants, chlorine-like can cause immediate symptoms of asthma in the absence of allergy.(2) Certain High-risk occupations can trigger asthma. Some of the examples of this occupation are-

  • Adhesive handling
  • Baking
  • Mill job
  • Carpet making(2)

What Is The Prognosis For Occupational Asthma?

The prognosis of occupational asthma depends on the avoidance of triggering factors and adherence to management plans (e.g., preventative medications). Prognosis also depends on the underlying causative agent and the severity of the individual’s symptoms.(3)

Occupational asthma is a type of asthma induced by exposure to a specific substance in the workplace. If a person is previously diagnosed with asthma, that aggravates at work is called work-aggravated asthma.(1)

Asthma is a chronic lung disease marked by reversible inflammation of the windpipes. This inflammation is mediated by the immune system, leading to temporary narrowing or constriction of the windpipes called bronchoconstriction. It is represented by symptoms like shortness of breath, wheezing, cough, and chest tightness.(1) There are two types of occupational asthma:

Immune-Mediated- this type is caused by an agent that stimulates the immune system of the body, thereby triggering asthma. It typically possesses a period (latency period) between the workplace exposure and the beginning of symptoms. This latency period can remain for a few weeks to several years.(1)

Irritant Induced- another type is caused by the agent that directly irritates the airways. It appears soon after exposure to the agent.(1)


Nearly 250 substances are identified as triggering agents for occupational asthma. These substances involve animal substances, plant substances, chemicals, metals, enzymes, and others mentioned above. The prognosis of this asthma depends on the triggering agents, time of exposure, management of the symptoms, and avoidance of the causative agent.


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