Occupational asthma and work aggravated asthma

Some people have asthma symptoms related to their workplace.

Some people have asthma symptoms (such as problems with their breathing, wheezing, coughing or a tight feeling in their chest) related to their workplace. This includes:

  • people who get asthma because of the work they do (known as occupational asthma) 
  • people who already have asthma but it's made worse by the work they do (known as work aggravated asthma).

One in 10 cases of asthma in adults (both new asthma symptoms and childhood asthma symptoms returning) is caused by work-related factors.

On this page we will explore the following questions surrounding occupational asthma and work aggravated asthma: 

Occupational Asthma

What is occupational asthma?

If you haven't had asthma before and then get it because of the work you do, you have occupational asthma.

How common is occupational asthma?

Occupational asthma is the most common cause of adult onset asthma and makes up 9 -15 per cent of cases of asthma in adults of working age.

  • In some industries up to 10 per cent of employees develop occupational asthma.

Why would someone get occupational asthma?

There are two types of occupational asthma depending on what causes it:

1) Allergic occupational asthma

This is the most common type of occupational asthma. Just like many people who have their asthma symptoms triggered by things they are allergic to (allergens) in the home or outside (such as house dust mites, pollution or pollens) some people can have their asthma triggered by allergens in the workplace (such as flour dust, animal dander or car fumes). You can read more about how allergens trigger asthma symptoms here.

Allergens that cause occupational asthma are called 'respiratory sensitisers' because they can cause changes in your airways, making them 'hypersensitive'. It takes a while for your immune system to become sensitive to an allergen, so you may have been able to do your work for weeks, months or even years before you start having asthma symptoms. But once you've become sensitive to an allergen, it can trigger asthma symptoms the next time you come in contact with it - even if it's just a small amount of the substance.

Chemicals commonly found in vehicle spray paint known as isocyanates; followed by additives used in bakeries called amylase are the most common substances causing allergic occupational asthma in the UK.

This is a list of jobs with the highest rates of allergic occupational asthma:

  • Vehicle spray painting - workers spraying cars and other vehicles are most often affected by a chemical called isocyanate (typically in 2-pack paints).
  • Baking - workers in bakeries, flour mills and kitchens can be affected by flour dust and enzymes which contain additives such as amylase.
  • Woodworking - people working in joinery and furniture industries can come into contact with dusts from hardwood, softwood and wood composite when it is machined or sanded.
  • Soldering - people who work in the electronics and assembly industries can come into contact with fumes from rosin-based solder flux during their work.
  • Healthcare work - there are two key substances that can cause asthma in healthcare workers.
    (1) Latex - natural rubber latex proteins have the potential to cause asthma if someone comes into contact with them regularly.
    (2) Diathermy - this surgical technique uses heat from an electric current to cut tissue or seal bleeding vessels. This process can give off invisible toxic gases, particles and vapours that may cause asthma symptoms.
  • Working with animals - people who work with animals - from pet shops to stable owners, laboratory workers to zookeepers - can be affected by animal fur, feathers, dander, dried urine and saliva dusts during animal handling and cage or enclosure cleaning. These dusts contain proteins known as 'animal aeroallergens' that can cause occupational asthma.
  • Working in agriculture - agricultural dusts are the most common cause of occupational asthma in this industry. People often come into contact with grain dust and poultry dust, or other dusts that are a mix of materials from fungal spores, bacteria, endotoxins, mites, animal dander and faeces, plant dust, soil, bedding, feed and feed components, chemicals, etc.
  • Engineering - people who work in machining or shaping can be exposed to metal working fluids (MWFs) which can cause occupational asthma if you inhale the mist or vapour.
  • Hairdressing - Hairdressers' bleach contains persulphate which can cause occupational asthma.

The most important thing to remember is that the reason you developed an allergy to something at work is because you were exposed to large amounts of the allergen for a long time which made you become sensitive to it.

There are many other respiratory sensitisers and more are being identified all the time. The Health & Safety Executive (HSE) publishes a list of the best known substances, which is updated regularly. You can also get top tips on avoiding occupational asthma for each of these industries.

2) Irritant-induced occupational asthma

This is a non-allergic type of asthma which happens when you breathe in a chemical at your workplace, and it irritates your airways, causing asthma symptoms. Irritant-induced asthma isn't very common and usually happens when there is an accidental chemical spillage in the workplace.

Examples of irritant chemicals include chlorine (used in swimming pools) and ammonia (which is a common cooling agent in refrigerators). If there is a chemical spillage at your workplace and you start to experience wheezing, coughing, breathlessness or chest tightness within 24 hours of the spillage, speak to your GP as soon as possible.

Could your asthma be occupational asthma?

Do the quick assessment below to see if there's a link between your asthma symptoms and your work:

  • Have your asthma symptoms started as an adult, or have your childhood asthma symptoms returned since you started working?
  • Do you have other symptoms, such as rhinitis (sneezing, itchy, runny nose) or conjunctivitis (itchy, red, and inflamed eyes)?
  • Do your symptoms improve on the days you're not at work (when you're on holiday, for instance)?
  • Do your symptoms get worse after work, or disturb your sleep after work?

You can speak to one of our asthma nurse specialists on 0300 222 5800 (9am - 5pm; Mon - Fri) if you would like to discuss your symptoms.

Keep an eye out for early warning signs...

You can help yourself by keeping an eye out for symptoms that may be an early sign of occupational allergy and asthma, such as:

  • Itching, sneezing or a runny nose - if you notice any of these symptoms and they're going on for longer than a few weeks, it could be an early sign that you're developing an allergy.
  • Shortness of breath, cough, chest tightness and wheeze - these symptoms are typical of developing an allergy because allergens in the air are also breathed into the lungs where they can cause irritation.

How is occupational asthma diagnosed?

Your GP might think you have occupational asthma if you tell them your symptoms are better on days you don't work, or when you're on leave. They will ask you questions about your job and the different substances you come in contact with, so it's useful to think about these things before you go see your GP. For example, do you notice your asthma symptoms start when you're around particular substances? Have a look at the list of jobs above that cause allergic occupational asthma to help you start thinking about what things in your workplace could be causing your symptoms.

Tests and tracking your symptoms

To help make the diagnosis of occupational asthma, your GP will refer you to a specialist in occupational medicine or your local chest clinic. The specialist may carry out a number of skin or blood tests and might also ask you to take measurements of your peak flow both at work and when you're away from work.

It's useful for you to complete a diary or chart of your symptoms over a few weeks, to see if there are any obvious work related patterns. Even though this may seem like a lot of effort, it's one of the best ways to determine whether or not your asthma is caused by your work - so try to keep at it!

In some cases where it's hard to find out exactly which substance at work is triggering your asthma, the specialist may get you to do a 'challenge test'. This test is only carried out in specialised centres under carefully controlled settings, while being closely monitored. During this test you'll be asked to breathe in substances thought to be causing your symptoms to see if any trigger your asthma symptoms. It's quite difficult to do this and takes a lot of time, so you will only be offered this if the cause of your asthma symptoms can't be found in other ways; or when your asthma is so bad that you can't risk any more exposure at work without knowing its cause.

Work Aggravated Asthma - When your work makes your asthma worse

If you have been previously diagnosed with asthma that wasn't caused by work, and find your symptoms (cough, wheeze, chest tightness, shortness of breath or itching and running of the nose) are worse when you're at work, you might have work aggravated asthma. A warning sign that you have this type of asthma is if you need to use your reliever inhaler (usually blue) or medicine more often during working hours. To confirm a diagnosis of work aggravated asthma, an assessment by a specialist in occupational lung disease can be useful - ask your GP to refer you.

Work aggravated asthma can be caused by various triggers in your workplace, such as exposure to irritant substances (for example, a fume-filled or dusty environment); changes in temperature (especially cold air); physical activity required by your job, such as lifting heavy boxes; or stress.

Will I always have occupational asthma or work aggravated asthma?

If you have allergic occupational asthma or work aggravated asthma, the substance that caused your asthma symptoms will always be a trigger for your asthma symptoms. For example, if flour dust is your trigger, it's sensible to avoid working in a bakery.

The only way to stop having occupational or work aggravated asthma symptoms is to stay away from whatever's triggering your asthma. For some people, their symptoms stop as soon as they stop contact, while for others it can take a little longer or symptoms may not go away completely - especially if you've had asthma for a longer time and have had more serious symptoms.

The best advice, if possible, is to avoid your work trigger for at least 12 months after your first work related asthma symptom.

Will I need to stop working because of my asthma?

Having allergic occupational or work aggravated asthma doesn't make you unfit to work. You should talk to your employer (and if you have one, your occupational health doctor or nurse) to see if changes can be made to your current job to make it safer for you, or if you can be given another role. Many employers will try to help you in these ways.

If your employer can't find you safe work you may need to look for another job. It's important to know exactly what caused your occupational asthma so this can be avoided in any new job. A specialist should have been able to identify this. If in doubt, seek advice from an occupational health professional.

There are three important things you can do to help manage your asthma symptoms so you can carry on working:

1) Try to avoid contact with the substance that's triggering your asthma symptoms:

  • try to get any allergens in your workplace removed or replaced with a safe alternative
  • your employer can reduce the risk by installing extractor fans or isolating you from the process linked to the the risk
  • you could also consider using respiratory protective equipment (RPE), which will prevent you from inhaling the respiratory sensitiser(s). Employers are responsible for implementing and managing RPE selection and use, or delegating that responsibility to another trained person. RPE comes in various forms such as helmets, visors, hoods or masks. You will need to make sure that the equipment fits well and is worn properly, removed safely and either replaced or maintained regularly.

2) Take your asthma medicine at the right time and in the correct way

Preventer inhaler: Taking your preventer inhaler regularly every day, and in the right way, means you're less likely to have asthma symptoms, or asthma attacks. Preventer inhalers help prevent asthma symptoms by preventing and reducing inflammation in the airways. And because preventers do this over the long term you'll be less likely to react to your asthma triggers, less likely to need to use your reliever inhaler, and more likely to be able to get on with your life without asthma symptoms holding you back.

Reliever inhaler (usually blue): In an emergency situation when your asthma symptoms come on, a short-acting reliever inhaler helps to get the medicine straight to the lungs, so it can relax the muscles surrounding your airways quickly. The airways open more widely, making it easier to breathe again. You should feel a difference to your breathing within a few minutes.

3) Use a written asthma action plan to help you manage your asthma

Having your own written asthma action plan is the best thing you can do to stay well with your asthma. You fill it in with your GP or asthma nurse and update it at every asthma review. It's your personal plan all about you and your asthma, telling you what to do:

  • every day to keep well
  • when you start to have symptoms
  • if you have an asthma attack

What if I can't avoid my work trigger(s) in my personal life?

If you have an allergy to a certain substance in your workplace, you'll have allergic symptoms whenever you come across it, at home or at work. If someone has occupational asthma to rats for example, we wouldn't advise that they keep rats as pets at home! If you have a flour allergy, baking an occasional cake at home won't harm - but running a home baking business isn't advisable.

In the short term, if you can't avoid your allergic trigger, your asthma medicine (and perhaps antihistamines too) can help. Speak to your GP or pharmacist about the best medicine for you.

What can my employer do to help?

Your employer has a duty under the Health Safety at Work Act 1974 to minimize any exposure to hazardous substances in the workplace.

If you're exposed to any allergens in the workplace, your employer should have explained this to you when you started work. You may be asked to complete a brief health screen check, including a breathing test at the start of your employment as well as every year you work there - to make sure you are not developing asthma.

Your employer should consult you (either directly or through your union or employee representative) about what needs to be put in place to help you. They may also consult with your occupational health nurse, doctor or respiratory specialist about the need to control respiratory sensitisers in the work place, and they should inform you of the steps they plan to take to do this.

If you do develop occupational asthma, your employer also has a duty to notify this to the Health and Safety Executive (HSE). Usually the HSE will then want to visit your place of work to see if there are ways in which other people can be prevented from getting the same problem.

Most employers will do what they can to help. If you don't think that they are doing enough you can:

  • raise the issue with the person responsible for health and safety in your workplace
  • contact your trade union or professional body
  • tell your manager about your concerns
  • contact the local HSE office (or the local council environmental health department) for advice
  • ask your colleagues not to smoke near you.

Can I get compensation if I get occupational asthma?

It may be possible to get compensation if you're diagnosed with occupational asthma. The level of benefit you get will depend on the severity of your disability. This will be assessed by a doctor on a scale of one to 100 per cent; you will get benefit if your disability is greater than 14 per cent.

It's important to claim your benefit as soon as possible. Payments will only start from the day you claim, not the day you found out you had asthma.

All workers: If you are told that your asthma has been caused by work, you should get advice quickly both about compensation through the courts and about benefits you may be entitled to. You may be eligible for Industrial Injuries Disablement Benefit.

Armed forces: If you develop asthma whilst serving in the armed forces, you may be able to get compensation through the Armed Forces Compensation Scheme.

Self-employed: The Industrial Injuries Disablement Benefit isn't available to people who are self-employed. You might be able to get Employment and Support Allowance (ESA) instead.

Can I take legal action against my employer if I develop occupational asthma?

You normally have three years from the time you know that you have asthma caused by work to start a court action. The sooner court proceedings can be started, the better it's likely to be for you.

You should consult a lawyer who has experience in occupational diseases.

If you're a member of a union then they will help you find an experienced lawyer. If you're not a member of a union, you can get free advice from your local Citizens Advice Bureau.

Last reviewed July 2016

Next review due July 2019