Occupational asthma is a type of asthma that is caused by inhaled irritant exposure at work. This condition is most often reversible. This means that its symptoms might go away once the irritants to blame for it are avoided. However, it is possible to have some permanent damage if there is prolonged exposure to irritants.

Here are some examples of irritants that can cause occupational asthma:

• Fumes
• Gases
• Vapours
• Dusts

Occupational Asthma Symptoms

While the cause of occupational asthma might differ from usual asthma, its symptoms are the same. For example, people with occupational asthma might experience shortness of breath, wheezing, nasal congestion, a runny nose, chest tightness, and eye irritation.

A person’s symptoms will likely worsen when they are exposed to the irritant(s) in the workplace. This is because the causes of occupational asthma can be non-allergenic or allergenic in nature. Usually, the person’s symptoms will improve when they are not at work. Still, often, the symptoms of occupational asthma will take several hours to appear after a person has been exposed to an irritant.

When the condition starts, a person might notice their symptoms subside over the weekend or when they’re on holiday. However, when exposed to an irritant, asthma can occur within 24 hours.

During later stages of the condition, the symptoms of occupational asthma might turn into a problem when the person is exposed to more common triggers, too, like smoke, changes in temperature and dust.

Which substances can cause occupational asthma, and which types of environment are the most prevalent?

Chemical dusts/vapours

Examples of these types of irritants are trimellitic anhydride, phthalic anhydride, and isocyanates. These are commonly found in workplaces dealing with upholstery and foam mattresses, packaging materials, insulation, polyurethane paint, and plasticisers.

Animal Substances

Substances like dander, bacterial dusts, protein dusts, hair, mites, and small insects are irritants for occupational asthma. These are found typically in jobs like farming, animal handling, kennel workers, veterinarians, and jockeys.

Organic Dusts

Coffee, tea, grains, flour, and cereals are all organic dusts that can cause occupational asthma. People who work as bakers, millers or other food processors are at the most significant risk.

Textile Dusts

Dusts from hemp, flax, and cotton are irritants for occupational asthma, which affects workers in the textile and cotton industries.

Metals

Workers in the metal factories or refineries dealing with chromium, platinum, nickel sulphate and soldering fumes are at an increased risk of developing occupational asthma.

Is it possible to prevent occupational asthma?

Occupational asthma can be prevented but often isn’t. Construction workers, for example, who suffer a high level of respiratory problems from to dust and other irritants should be provided with the correct personal protective equipment to prevent asthma and other conditions. Avoiding triggers is the best way to prevent occupational asthma.

If symptoms of asthma do occur, it might be necessary to change roles. However, steps can be taken to reduce the risk of developing occupational asthma:

• Change work processes to handle workers’ exposure to irritants better
• Employ industrial hygiene techniques and keep levels of exposure to a minimum
• Ensure medical checks occur regularly and check for possible lung damage and other health conditions that could be related to the exposure of irritants
• Be aware of and medical history with asthma that puts people at an increased risk of developing occupational asthma if they work in specific industries

It’s not known just how much smoking tobacco contributes to the development of occupational asthma. Still, workers who smoke are more likely to develop lung problems like occupational asthma when compared to non-smokers, in general.

How do doctors diagnose occupational asthma?

There will be a detailed medical history taken as well as a medical examination to allow the doctor to establish whether or not there is a relationship between symptoms and exposure to irritants at work.

There are also many other diagnostic procedures that might include a pulmonary function test before work and after work to detect whether or not the airways are becoming narrower after exposure.

There are also tests like blood tests, sputum tests and chest x-rays that help to rule out other lung conditions that could be causing the problems.

Questions you may be asked:

• Have your symptoms of asthma started in adulthood?
• Have your symptoms of childhood asthma returned since you began working?
• Do your symptoms improve when you’re not working or when you have a holiday from work?
• Do you notice that your symptoms are worse after work, and do they disturb your sleep when you have been to work that day?
• Do you have any existing allergies that might increase your risk?
• Do you have a diagnosis of rhinitis?

Possible tests for diagnosing occupational asthma

• Peak flow test – you might be required to fill in a peak flow diary to see how your peak flow differs when you’re at work and when you’re at home. Typically, people are asked to do four peak flow readings per day for around three weeks.
• Skin prick or blood tests to confirm allergies – If asthmatic symptoms are triggered by an irritant, they won’t show up.
• Challenge tests – in a challenge test, you’re required to breathe in substances that might be causing symptoms. Since this is a difficult test, it would only be done under supervision.

How is occupational asthma treated?

The first way to treat occupational asthma is to avoid exposure to the substance or substances that trigger the symptoms or the asthma. People who have occupational asthma should also ensure they don’t inhale other irritants like nitrogen oxide, chlorine, and sulphur dioxide since these substances are known to make the symptoms of asthma more severe. Medications may also be prescribed to control asthma symptoms. For advanced occupational asthma, a patient might need medication, physical therapy, or breathing aids.

What the law says

Under the Health and Safety at Work Act 1974, employers have to minimise exposure to hazardous substances. This includes allergens and irritants. Therefore, if you develop occupational asthma, your employer has to notify the Health and Safety Executive (HSE). In cases where a worker has developed occupational asthma because of employer negligence in following health and safety regulations, they may be in a position to claim compensation.

If you work with allergens and irritants, you should be having regular health checks to ensure you are not developing occupational asthma.