What are the other Names for this Condition? (Also known as/Synonyms)

• Asthma due to Occupational Exposure
• Irritant-Induced Reactive Airways Disease
• Work-Related Asthma

What is Occupational Asthma? (Definition/Background Information)

• Occupational Asthma is a narrowing and swelling of the airways of the lung, which is caused by exposure to substances found in the individual’s workplace
• The most common substances that cause the condition include chemicals, fungi, wood dust, grain dust, and dander
• There are two main forms of Occupational Asthma:
  • Immunologic Asthma: It is caused by sensitization to the substance causing the asthma. This usually occurs after a period of regular exposure to the substance
  • Irritant-Induced Asthma: This occurs right after the individual has been exposed to the irritant. It does not display a time-interval or latency, after exposure to the substance. This condition is also known as Reactive Airways Dysfunction Syndrome (RADS)
• The two biggest risk factors are asthma (outside of the workplace) and family history of allergies to substances that are commonly found at one’s workplace
• The main signs of Occupational Asthma are similar to normal asthma, which are shortness of breath and wheezing. The diagnosis is generally made by confirming the asthma through various tests and by identifying wheezing
• Avoiding trigger substances is the best form of treatment of Asthma due to Occupational Exposure. However, in acute cases, bronchodilators may be used

Who gets Occupational Asthma? (Age and Sex Distribution)

• In principle, any individual can develop Occupational Asthma, if an irritant or allergen is present in high-enough concentrations
• However, individuals who work in industries that use chemicals are most likely to develop this lung disease
• Occupational Asthma is believed to account for about 15% of all asthma cases in the industrialized nations; it is a global condition
• Generally, men are more at risk than women, due to the type and nature of occupation they are involved with
• There is no particular racial or ethnic preference noted

What are the Risk Factors for Occupational Asthma? (Predisposing Factors)

The risk factors of Occupational Asthma may include the following:

• Family history of allergies to substances present at the workplace of the individual
• Smoking
• The presence of asthma, even before employment
• Atopy (a genetic predisposition to produce greater than normal immune responses)

Common trades and professions that are at high risk for Asthma due to Occupational Exposure include:

• Agriculture, farming
• Mining
• Manufacturing (plant, equipment, and machine operators)
• Transportation
• Chemical industries and labs
• Construction
• Animals and animal-related product works
• Wood and wood-related products

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Occupational Asthma? (Etiology)

Occupational Asthma may occur in the following manner:

• The irritant enters the body through inhaled air. From there, asthma can be induced in 2 ways
• Firstly, the irritant can directly cause inflammation and swelling of the airways
• If the individual has been exposed to the irritant repeatedly, the individual may develop allergic antibodies. The allergic reaction that results is the second way in which the asthma may occur
• The allergens could be organic dust, metal-based (fumes), wood-based, agriculture products related, industrial chemicals (organic and inorganic), microorganisms, etc.

What are the Signs and Symptoms of Occupational Asthma?

The signs and symptoms of Occupational Asthma are the same as asthma. These include:

• Shortness of breath
• Wheezing
• Coughing
• Tightness in the chest
• If the asthma occurs at work, but not outside of work; it is a sign that the individual is suffering from Occupational Asthma
• However, sometimes symptoms may not occur until 12 hours after the individual is in contact with the irritant. This can mean that a individual may have symptoms outside of work
• In some individuals, symptoms of allergic rhinitis or allergy-induced conjunctivitis may precede the symptoms of Occupational Asthma

How is Occupational Asthma Diagnosed?

A diagnosis of Occupational Asthma may involve the following tests and procedures:

• Complete physical exam with thorough medical history evaluation with details of occupation, work environment, etc. The physician will use a stethoscope to see if wheezing is occurring
• In individuals with symptoms, the healthcare provider may conduct the following tests:
  • Blood tests to determine the presence of antibodies to potential irritants
  • X-ray of the chest
  • Bronchial provocation test (allergy test for the airways)
  • Pulmonary function tests (to determine how well the individual is inhaling and exhaling); a comparison of the peak flow meter results at work and home are made
  • Complete blood count (CBC)
  • Allergy skin test
  • High resolution CT scan of the lungs
• The physician may refer the individual to an allergy/immunology specialist, to determine what specific substance is triggering the asthma, if the physician suspects that the individual has Occupational Asthma

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the Complications of Occupational Asthma?

Complications due to Work-Related or Occupational Asthma include:

• Development of full-blown cases of adult asthma
• There is a high-risk for many respiratory diseases and infections
• Interstitial lung disease due to long-term accumulation of the allergens/chemicals in lungs
• Lung cancer
• Prolonged absence from work, compensation for employers, decreased productivity, legal and regulatory complications

How is Occupational Asthma Treated?

Prevention of Occupational Asthma is the best form of treatment. This may be achieved by avoiding contact with the irritant causing the asthma.

• Bronchodilators (inhalers) are used to help alleviate the symptoms
• Asthma-control medications (to be taken daily) may also be prescribed

How can Occupational Asthma be Prevented?

It is possible to prevent Occupational Asthma in most cases. The following points may be considered:

• Avoid inhalation of and contact with the irritant, by working in a new environment, where the irritant is not present or by removing the irritant from the current workplace (if possible)
• Use protective breathing equipment (face masks) at work
• There should be a ‘Material Safety Data Sheets’ at the workplace, which gives in-depth information about the chemicals that an individual may be exposed to at the workplace
• Enforcing any governmental regulations on workplace safety and exposure to pollutants, chemicals, irritants, and such substances
• Creating an awareness amongst the workers and employers about the various substances that they may be exposed to at their workplace, and the possible health effects of these substances; especially for those who work in high-exposure risk areas

What is the Prognosis of Occupational Asthma? (Outcomes/Resolutions)

• If the individual avoids the problem-causing substance or chemical, the Asthma due to Occupational Exposure will likely go away in the future. The prognosis in such individuals is generally excellent
• If the individual continues to get exposed to the asthma-causing substance, the asthma will persist and the condition may even worsen. The prognosis in such individuals is guarded
• Some symptoms may last for years, even after exposure to the irritant has stopped

Additional and Relevant Useful Information for Occupational Asthma:

• Isocyanates are the amongst most common class of chemicals, which causes Occupational Asthma
• Occupational rhinitis has been linked to Occupational Asthma in certain studies
• Workplace safety governmental regulations are maintained in the US, by the US Department of Labor Occupational Safety & Health Administration