Work-related and occupational asthma
Up to 15% of newly diagnosed asthma cases in adults are related to exposure to agents encountered at work and up to 3,000 cases of occupational asthma occur per year in Australia. If you experience asthma symptoms at work, and these symptoms improve when you are away from work, e.g. during holidays or on weekends, you may have what is called work-related or occupational asthma. Occupational asthma can occur in many types of workplaces, but is most commonly reported where people are working with flour and isocyanates (chemicals which are found in paints as hardening agents).
Work-aggravated asthma is different from occupational asthma, which occurs when there is sensitisation to a substance encountered at work. Work-aggravated asthma occurs when people who already have asthma are exposed to factors such as gases or fumes, smoke, dust or cold dry air which irritate the airways causing asthma symptoms to occur and make a pre-existing condition worse.
What causes occupational asthma?
Over 4000 substances in the workplace (known as sensitisers) may cause asthma. Repeated exposure to these sensitisers over a period of time (usually years) may produce permanent asthma symptoms identical to non-occupational asthma. This usually takes weeks or years to develop.
What are the symptoms of occupational asthma?
Symptoms include wheezing and coughing, shortness of breath and tightness across the chest. Often these symptoms will develop after irritation is noticed in the nose and eyes. Other workers may be affected or may have left the job because of these symptoms.
Symptoms may vary during the working week or shift. In the early stages of exposure, symptoms tend to improve when the worker is away from work. However, once the airways are sensitised, continued exposure even in small amounts can produce symptoms. Continued exposure may also lead to more symptoms and eventually to permanent asthma in some people.
How do I know if I have occupational asthma?
If you suspect something is affecting your breathing at work, go and see your doctor. They will ask you questions about your symptoms and your work, and carry out tests such as a spirometry test to decide if you might have occupational asthma. They may also ask you to keep a diary of your symptoms to compare with your working hours. There is also a software program available which can automatically compare your peak flows with your working shifts. This can be downloaded free from the Oasys website.
It can be very difficult to distinguish between true occupational asthma and work exacerbated asthma, and it may be necessary for your GP to refer you to a respiratory specialist with expertise in this area.
You can find out if you are exposed to something which is recognised as causing occupational asthma, by looking at the Material Safety Data Sheet (MSDS) which your employer should provide on request, or by contacting WorkCover (www.workcover.(insert your state).gov.au) or by visiting some of the following websites:
Note: If you are working with known sensitisers, it is the responsibility of your employer to ensure that there is adequate ventilation and respiratory protection e.g. a mask.
Common sensitisers and occupations where workers may be exposed
Agent
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Example occupations
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Wood dust (e.g. western red cedar, redwood, oak)
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Carpenters, builders, sawmill workers, sanders, model builders
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Isocyanates
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Automotive industry, mechanics, painters, adhesive workers, chemical industry, polyurethane foam workers
|
Formaldehyde
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Cosmetics industry, embalmers, foundry workers, hairdressers, laboratory staff, medical personnel, paper industry, plastics industry, rubber industry, tanners
|
Platinum salts
|
Chemists, dentists, electronics industry,
photographers, metallurgists
|
Latex
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Health care workers, textile industry, toy
Manufacturers
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Flour and grain dust
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Bakers, cooks, pizza makers, grocers, farmers, combine harvester drivers
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Animal allergens (e.g. urine, dander)
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Veterinary surgery workers, animal care workers, laboratory workers, jockeys, animal breeders, pet shop employees
|
Table adapted from Hoy, R., Abramson, M., Sim, M. (2010). Work related asthma. Diagnosis and management. Australian Family Physician, 39 (1/2), 39-42.
What is the treatment for occupational asthma?
Early diagnosis and management by removing any exposure to irritants in the workplace is the best way to treat occupational asthma and prevent it becoming a permanent condition. Otherwise, treatment with the usual asthma inhalers is usually effective.
Note: Occupational asthma does not always mean having to leave your workplace, as workplace strategies can be developed. For example, if exposure cannot be minimised or ceased, then employers must provide adequate respiratory protection and/or substitute the irritant substance with a known non-irritant. This is a part of Occupational Health and Safety requirements. More information is available from your State or Territory Workcover authority www.workcover.(insert your state).gov.au
If you develop asthma symptoms at work, or your existing asthma gets worse, it is essential that you visit your doctor for tests and an accurate diagnosis. If you did not already have a diagnosis of asthma and/or a written Asthma Action Plan , then this should be provided to you.
What if I only had temporary symptoms?
If you have inhaled a high dose of a substance that causes damage to the airways, possibly as part of an industrial accident or spillage, you may temporarily experience breathlessness and wheeze similar to asthma. This is called Reactive Airways Dysfunction Syndrome (RADS). Symptoms usually occur within 24 hours of a single exposure to very high concentrations of a chemical spill, irritant gases, corrosive mists or solvent vapours. Usually, symptoms will gradually improve as your airways heal, but occasionally workers can be left with permanent symptoms. It is very important to have a medical check if this does happen, and to make sure your work environment is safe.
See also
Asthma triggers