A trigger is something that makes asthma worse or brings on an attack. Triggers are different for everyone and often it’s not just one trigger that sets off an asthma attack but a combination of several triggers around the same time. Knowing as much as you can about your asthma triggers is important so that you can avoid or reduce your exposure to them, making your asthma easier to handle.


Asthma Trigger Animal Dander

Many families choose a cuddly cat or dog for their family pet, however these seemingly harmless pets can trigger asthma in some people. Allergens can be found in their saliva, hair, urine and dander (dead skin flakes) and are carried in the air on very small particles. The pet’s dander, which is shed on carpet and upholstery, is also a food source for the dust mite. 

Symptoms may occur within minutes of being exposed to the pet, but for some people symptoms may build up over several hours and be most severe 12 hours after initial contact with the pet. If a pet comes inside, its sheddings become part of the house dust and are present even when the animal is outside, which can make it difficult to recognise the pet as an allergen. In general, cats produce more severe allergic reactions than dogs, and are the second major source of indoor allergens as theirs tend to stay in the house for long periods. They are not a good choice of pet for families with members who have asthma or allergies. Other pets do not seem to produce such potent allergens, but birds, dogs, rabbits, guinea pigs, rats and mice carry allergens that could trigger asthma.

The ideal solution is to remove the pet from the home and, wherever possible, avoid contact with other pets or the homes they inhabit.  Although keeping a furry pet is discouraged if it triggers asthma, there are ways to minimise exposure to its allergens:

  • Keep your pet out of the bedroom and any other areas where a great deal of time is spent.
  • Always wash your hands after touching or feeding your pet
  • Keep pets off chairs, sofas and other soft furnishings
  • Vacuum any carpets, curtains and upholstery regularly using a vacuum with a motorised brush and a HEPA filter
  • Clean hard floors with a damp cloth or a steam mop
  • Clean air-conditioning and heating ducts
  • Wash clothing, and pet and human bedding regularly in hot water
  • Groom (e.g. brush) your pet regularly.
  • Washing dogs may also reduce the amount of allergen released into the environment. Consult a veterinarian for advice regarding the pet’s skin care to prevent excessive dryness due to frequent washing.

Make sure to ask a non-allergic friend or family member to vacuum, dust and brush the pet, and to do so outside so that any loose hair and allergens from the pet are not shed indoors. The animal's litter box or cage should be cleaned out regularly and again, this is a task for a non-allergic person. 

Pet allergens accumulate in areas such as carpets, mattresses, cushions and curtains as well as horizontal surfaces. The allergen particle is so small that it passes through fabric, so it is suggested that mattresses and cushions be covered with suitable coverings to prevent the release of allergens when squeezed.

Have the pet sit on a washable sheet that should be changed and washed daily. Using a vacuum cleaner with a HEPA filter system may help prevent the release of the allergen, but the best solution is to have polished floors, or floor coverings such as lino, slate or tiles. Remember when using a vacuum cleaner to regularly change the filter.


Some people find that their changing emotions such as being worried, uptight, stressed, excited or happy, can make their asthma worse. At times you may need professional help to balance your emotions, and your doctor will be able to refer you to an appropriate professional.

Workplace Triggers

Workplace Fumes

If something at work is affecting your asthma, you might feel that your asthma gets worse soon after starting a new job or while you are doing a particular part of your job, or that your asthma improves when you are not at work. Some common New Zealand work place triggers are:

  • Isocyanate paints
  • Foams and plastics, and the fumes given off during their manufacture
  • Animal fur and protein from laboratories and veterinary clinics
  • Flour and grain dusts from farms, granaries and bakeries
  • Wood dusts
  • Epoxy resins and other plastics from boat builders, mould manufacturers and plastic manufacturing processors

Sometimes people who have not had asthma before can develop asthma through an allergic reaction to a substance in the workplace. This may happen even after years of working safely with the substance. Sometimes the allergic reaction and its symptoms don’t develop until some hours after the exposure. It is therefore often difficult to identify the workplace as the cause. Other people develop asthma for the first time in the workplace after heavy exposure to irritants of the breathing tubes, such as welding fumes or gaseous vapours like sulphur dioxide.

Common substances or processes recognised as causing asthma problems include:

  • Working with chemicals such as those used in some paints and glues, foam manufacture etc, or expoxy resins. Common industries include spray painting and boat building.
  • Working with wood dusts. Problem dusts include western red cedar, rimu and some particle boards (building and joinery industries)
  • Being exposed to metal fumes or dusts (aluminium smelting, welding, etc)
  • Being exposed to dusts from organic sources such as flour, animals, insects, etc.

The prevalence of occupational asthma is higher in smokers.

What can you do?

Talk about the problem with your doctor or the occupational health nurse if one visits yours workplace. The doctor will ask you to note what substances or processes you are exposed to in your work, if your symptoms worsen during each shift or if there is any improvement away from work. They can also teach you how to use a peak flow meter. This measures how fast you can breathe out and tells you how wide your breathing tubes are.
If a workplace process or substance is causing or making your asthma worse, there are several steps that you can explore with your employer to lessen the problem. They are:
Can the substance or process be changed for something less harmful?
Can the substance or process be isolated to a special place in the worksite or time of day when most people will not be exposed?
Can the equipment be improved to reduce the exposure?
What can you or your employer do if you are not sure if there is a problem at work?
WorkSafe New Zealand can be contacted in the telephone book for advice. They have the resources to provide information and advice about workplace hazards and the best (and most practicable) means of controlling these problems if they exist. Your union may also be able to offer help.

Click here to download a free pamphlet on Asthma in the Workplace.

Colds and the Flu

Asthma Flu Jab Photo

Colds and ‘flu viruses along with throat and nose infections can bring on asthma episodes. The first signs are usually a blocked or runny nose or a sore throat. Everyone with asthma should consider asking their doctor for the ‘flu vaccine. Vaccinations are free of charge for people with asthma, and should be done once a year to stay protected from any new strains.

As soon as the first snuffle or blocked nose appears, follow your Self Management Plan as you may need to increase the dose of your medicine/inhalers. Record your peak flow and or your symptoms to check your progress.  See your doctor if your asthma gets worse.

Exercise Induced Asthma

Physical activity is especially important for people with asthma. Physical activity improves our lung capacity and blood flow and is calming, fulfilling and fun. However, for many people with asthma, physical activity can trigger symptoms during or after exercise, such as wheezing, tightness of the chest, or coughing. Some people think they are getting older or are unfit, but they might have Exercise Induced Asthma (EIA). The good news is that it is easy to find out if you have EIA. Ask your doctor, nurse or Asthma Society for a peak flow meter. Take your peak flow reading before and after exercise. If your peak flow rate drops 20 percent after exercise then you have EIA.

What causes it?

Researchers believe that the cool air you breathe when you exercise dries the lining of your breathing tubes. This triggers your breathing tubes to spasm and become tight. Some people who get EIA end up avoiding activity, rather than managing their asthma effectively. However EIA needn’t slow you down. Almost everyone with asthma can lead an active life. If you can’t exercise without getting asthma, see your doctor. Remember that being physically active is an important part of your asthma management, and shouldn’t be avoided. Once your asthma is well-managed, you should be able to exercise without symptoms.


Triggers in the air include factory smoke and car exhaust fumes, cigarette smoke, fly sprays, strong perfumes and aerosol cleaning sprays. Smoking should be avoided after your baby is born as well as during pregnancy. Exposure to tobacco smoke is linked with wheezing in the newborn, increased frequency and severity of asthma symptoms in children with asthma as well as Sudden Infant Death Syndrome (SIDs). Some building materials and home furnishings give off fumes that might make asthma worse, such as formaldehyde which may be found in paints, wall boards, medium-density fibreboard (MDF), adhesives and more. Where options without formaldehyde (or with low levels) are available, we recommend those. Paint and other coatings have been a major source of volatile organic compounds (VOCs) and may cause respiratory irritation. We recommend low (or no) VOC paint, or thoroughly airing freshly painted rooms.  


A number of medicines may aggravate asthma in some people. Not everybody with asthma is sensitive to these medicines, however their use should be discussed with your doctor. Always read the information leaflet and any warning labels on all products. This includes medicines from the pharmacy, supermarket, health food shops and other sources. Whenever consulting anyone about your health, do make sure that you tell them you have asthma. Aggravating medicines include:

  • those which contain aspirin or acetylsalicylic acid;
  • some medicines taken for heart disease, blood pressure or eye conditions; and
  • non-steroidal anti-inflammatory drugs.

What can I do to avoid problems?

Be aware of the medications that can cause potentially serious attacks. These include aspirin and other non-steroidal anti-inflammatory drugs used in pain relief products, as well as some natural health tonics such as royal jelly. You should check that any products taken for the relief of symptoms (including colds, flu and pre-menstrual syndrome) do not contain aspirin or ibuprofen.

If a reaction or worsening asthma symptoms are experienced following the use of any medicines or product, report the adverse reaction to your doctor.

What pain relievers are recommended?

Paracetamol is the safest medication for occasional use to treat pain or colds and flu. Recent research has suggested that the longer term use of high doses of paracetamol can aggravate asthma. Aspirin or acetylsalicylic acid is freely available from supermarkets and pharmacies, and is widely used for the treatment of pain, fever and inflammation. It is particularly useful for rheumatic and arthritic conditions as well as reducing the risks of blood clotting. Apart from the possibility of severe reactions in some people with asthma, aspirin is a very useful drug that is both safe and effective.

Examples of aspirin based products are: Aspec, Alka Seltzer, Aspro and Aspro Clear, Cardiprin, Cartia, Disprin, Codcomol, Solprin, Codral Forte, Pirophen.

Examples of products containing salicylates are: Bonjela, Orased Jel, Applicaine.

The following medicines are Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) that may trigger asthma in some people:

  •  Ibruprofen (Brufen, Nurofen, Anafen, Motrin. Panafen)
  • Naproxen (Naprosyn, Synflex, Naxen, Noflam)
  • Keptoprofen (Orudis, Kefen, Oruvail)
  • Indomethacin (Indocid, Arthrexin, Rheumacin)
  • Sulinac (Clinoril, Daclin)
  • Diclofenac (Voltaren, Apo-Diclofenac, Affenax, Diclax, Cataflam, Flameril)
  • Mefenamic Acid (Ponstan)
  • Piroxicam (Feldene, Candyl-D, Apo-Piroxicam, Piram-D)
  • Diflunisal (Ansal)
  • Tenoxicam (Tilcotil)
  • Tiaprofenic Acid (Surgam)
  • Flurbiprofen (Froben).

Beta blockers are commonly used to control high blood pressure and may trigger asthma in some people.

The following medicines are Beta Blockers which may have an effect on asthma:

  • Acebutolol (ACB)
  • Atenolol (Lo-ten, Tenormin, Anselol, Apo Atenolol, Globel Atenolol)
  • Celiprolol (Selectol, Celol)
  • Labetalol (Hybloc, Trandate)
  • Metoprolol (Betaloc, Lopressor, Slow-Lopressor)
  • Nadolol (Apo-Nadolol)
  • Oxprenolol (Transicor, Captol)
  • Pindolol (Pindol, Apo-Pindolol)
  • Propanolol (Angilol, Cardinol)
  • Sotalol (Sotacor)
  • Timolol (Blocadren, Hypermol)
  • Beta blockers with a diuretic: Tenoret, Tenoretic, Viskaldix.

The following medicines are beta blocker eye drops (for Glaucoma) which can affect asthma:

  • Betaxolol (Betoptic)
  • Levobunolol (Betagan)
  • Timolol (Timoptol, Timpilo, Hyoptol)

Pollen and Plants

Asthma Triggers Allergy

A number of plants are associated with triggering asthma and hay fever symptoms in some people. As a general rule, wind-pollinated plants tend to be more problematic than plants pollinated by insects or birds, as their lighter, smaller pollen is more likely to become airborne and get inhaled. Deciduous plants which release pollen from insignificant-looking flowers are in this category.

Commonly found “problem plants” in New Zealand include:

Olive trees have also recently been identified as an increasing problem as they become more widely grown here. Other shrubs and trees which are fairly common and can trigger symptoms in some people include alder, ash, coprosma, cypress, elm, liquidambar, maple, mulberry and plane trees. Flowers in the Asteraceae family can also be a trigger – these include daisies, marigolds, and chrysanthemums.

Bird and insect-pollinated plants with large, flamboyant flowers are less likely to trouble people with asthma and allergies. However, bear in mind that strongly scented plants can affect some people.

For individuals who are affected, the best solution is avoidance:

  • Remove any plants that trouble you from your garden.
  • Try to avoid going out on windy days.
  • Keep windows closed, particularly when out in the car. Some vehicles have air intake filters fitted, which help reduce the amount of pollen taken into the car.
  • Use your Self Management Plan to help you adjust your medications as your asthma gets worse/better
  • For hay fever symptoms, continue using your nasal spray if you have one
  • Use pollen forecasts to help you gauge the likely risk of exposure to your triggers. MetService includes pollen levels in their forecasts – www.metservice.co.nz
  • Try to find out more about your allergic triggers with a skin prick test (see our Asthma and allergy fact sheet for more information.)
  • Mowing, weeding and hedge-trimming can stir up pollen, dust and spores which are then inhaled at close quarters. If you are sensitive to any of these, have someone else mow your lawns and keep your hedges in shape, and stay inside while it’s done. If you have to perform these tasks yourself, wear a mask which will help reduce exposure.
  • As a longer-term alternative, you may wish to consider replacing lawns with paving or plantings, and replacing hedges with fencing or trellis. Minimise your weeding with appropriate ground cover plants and mulches.
  • If mould spores are a trigger for your asthma, avoid organic mulches such as tree bark and manures, and use gravel mulch instead. As composting depends on moulds as well as bacteria, have someone else manage your compost. Exercise caution with potting mix – open bags slowly, and away from the face.


Changes of temperature can affect people with asthma, so try to keep your home at an even temperature. It may help to use a thermostatically-controlled heater in the bedroom at night to keep the temperature around 18 degrees C. Wearing a thin, warm scarf loosely around your lower face can help warm the air you breathe, and if you know that certain weather affects your asthma you may need to increase your medicine during that time.

Asthma across Aotearoa

Current research studies indicate that there aren’t “good” or “bad” areas for asthma as such, but that the prevalence of asthma is fairly similar across New Zealand. In addition, people have such different individual responses to their environment that it’s almost impossible to predict how a move might affect their condition. Some people find that their asthma improves for some months or longer after they move, though the asthma may then return to the previous level of severity. This may be to do with the person’s sensitisation to the environment but it is hard to determine, as it takes some time to become sensitised to a new environment to the point that they develop an allergic response.

If you are thinking of moving to a new place and you know your asthma is affected by triggers such as pollen, it would be advisable to look into how prevalent the trigger is there. It is also important to consider your indoor environment and how your asthma might be affected by moving to a different house or flat. For example, if your new home is poorly ventilated, damp, has old carpets, or uses unflued gas heating, your asthma may deteriorate. If the previous owner has had a cat or a dog, bear in mind that allergens from these animals may remain in the house for up to six months.

Moving to a new area or home can also be stressful, and this may have an impact on your symptoms too. Our advice is to keep monitoring your asthma after you move and make any necessary adjustments in line with your Self Management plan. If your asthma changes significantly, see a doctor.

You may also wish to make contact with a regional partner in your area as they can provide you with free advice and information about local services.

For more information on allergies or to learn about some common asthma triggers visit the Allergy NZ website.

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