Being aware of asthma triggers

Common asthma triggers include colds and flu, tobacco smoke, and exercise, though people have individual responses and not everyone reacts to the same thing. Identifying what triggers your asthma is helpful in allowing you to avoid the trigger or take extra measures to control your asthma when exposed to this. 

Effect can be immediate or delayed

Triggers usually have an effect on you straight away but sometimes take effect slowly over several hours. Keeping a peak flow rate or symptom diary will help you work out which triggers affect you.

Often, it's not just one trigger that sets off an episode of asthma but a mixture of several.

What are the most common triggers?

The most common asthma triggers are:

• colds and 'flu' viruses
• cigarette smoke
• exercise and activity
• allergies
• chemicals and dusts at work
• temperature and weather changes
• emotions
• fumes 
• household sprays
• some medicines.

Colds and flu

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. You cannot always stop yourself catching these infections so deal with them as they appear. Everyone with asthma should consider asking their doctor for the annual "flu" vaccine.

What should I do?

• as soon as the first snuffle or blocked nose appears, follow your self management plan
• use your peak flow meter or record your symptoms to check your progress
• see your doctor if your asthma gets worse.

Cigarette or marijuana smoke

Around three-quarters of people with asthma become wheezy in a smoky room. It has been shown that children with asthma whose parents smoke, have more asthma symptoms than children of non-smokers. Also, exposure of young babies to exhaled or second-hand smoke increases their risk of developing asthma and bronchial problems. Inhaling marijuana smoke is just as harmful to the lungs as cigarette smoke.

What should I do?

• if you smoke, try to quit.
• if friends or family smoke, explain how it affects your asthma and encourage them to quit or smoke elsewhere
• avoid being near people who are smoking.

For help with quitting contact your doctor or the Quit Group (details at end of article under 'Further information and support'). Also see: Smoking and asthma

Exercise and activity

Wheezing, tightness of the chest, or coughing during or after exercise shows that this is triggering your asthma. If your asthma is well managed, you should be able to exercise without these symptoms.

If you can't exercise without getting asthma, see your doctor. Remember that physical activity will help your asthma overall. It's better to manage your asthma effectively, allowing you to exercise, rather than avoiding activity.

For helpful tips on managing asthma with exercise see: Asthma, breathing and exercise

Temperature and weather changes

Changes of temperature and weather can affect people with asthma.

What should I do?

• 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 20 degrees C
• wearing a thin, warm scarf loosely around your lower face can help warm the air you breathe
• if you know that certain weather affects your asthma you may need to increase your medicine during that time.

Fumes

Triggers in the air include not only factory smoke and car exhaust fumes, but also cigarette smoke, fly sprays, strong perfumes and aerosol cleaning sprays. Some building materials and home furnishings may give off fumes that might make asthma worse. Formaldehyde in particle-board is one of these.

What should I do?

• try to find what the trigger is
• always carry your reliever medication with you
• seal particle-board floors, shelves, stairs, and household fittings with polyurethane or an oil-based paint
• ensure your home is well ventilated so fumes do not accumulate.

Medicines

The common groups of medicines that can trigger asthma are:

Beta blockers

These are used (in tablet form) to treat a number of illnesses - including high blood pressure, heart conditions, migraine - as well as in eye drops for glaucoma. If you are discussing any of these conditions with your doctor remember to tell him or her that you also have asthma.

Aspirin and non steroidal anti-inflammatory (NSAID) pain relief

One in 20 people with asthma is sensitive to aspirin and other medicines for pain relief, such as the various non-steroidal anti-inflammatories (NSAIDs). If aspirin or NSAIDs trigger your asthma, make sure when you buy any pain relief products that you read the packet carefully (or check with your pharmacist). And remember, children under 12 years should not be given aspirin.

Natural products

It is important to remember that 'natural' does not necessarily mean the product does not have harmful side effects. Products containing bee pollen, 'royal jelly' or echinaecea have been found to be harmful to people with asthma.

Emotions

You may find that your changing emotions, such as being worried, uptight or stressed, or being excited and happy, can make your asthma worse. The part your emotions play in your asthma can be difficult to pinpoint. If you are aware that your feelings may be making your asthma worse, you may need professional help to balance your emotions. Your doctor may be able to assist or refer you on to the appropriate person.

Allergies

Some people are particularly sensitive or "allergic" to certain things they come into contact with every day. These allergies are important in hayfever and eczema as well as asthma. Hayfever causes itching, a runny nose and sneezing. Eczema causes redness and itching of the skin.

The most common asthma-producing allergies are related to:

• house dust mites
• animals
• pollens
• moulds
• fungal spores
• certain food and drinks.

House dust mites

House dust mites are tiny creatures which live in areas such as bedding and carpets. Dust mite faeces and waste products, which are very tiny and float in the air, can provoke an allergic reaction when inhaled. Allergies to dust mites are very common.

Also see: Asthma and house dust mites

Cats and other animals

Cats are the second major source of indoor allergens (after house dust mites). A high proportion of New Zealand families have cats, and the allergens they produce tend to stay in the house for long periods. They are not a good choice of pet for families with people who have allergies. Other pets do not seem to produce such potent allergens, but dogs, rabbits, guinea pigs and mice can cause problems in some people.

What should I do?

• never allow pets into the bedroom and, if possible, keep them outside the house
• if you are visiting friends or family who have furry animals take extra medication beforehand, or ask them to visit you. People will understand if you explain why.

For more tips, see Pets and asthma

Food and drink

The foods most commonly associated with food allergy are cow's milk, wheat, seafood, eggs, soy and peanuts. The main symptoms are hives, eczema, itching, vomiting, diarrhoea, abdominal pain, nasal congestion and wheeze.

Mild allergy affecting asthma occurs in probably one out of 50 children under the age of two years. Most childhood allergies are out-grown by the age of three. In older children and adults it is less frequent, affecting about one in 500 people. If the common foods causing allergies are not introduced to a child's diet until they are two years old, they are less likely to develop lifelong allergies.

In severe cases, food allergies can cause anaphylaxis (severe allergic reaction) which requires urgent medical attention. Early signs can be swelling of the face, tongue and mouth.

Some people find their asthma is triggered by certain foods or additives in food - a common example is metabisulphite, a preservative added to some soft drinks, wine and pickles.

Other people with asthma are very intolerant of foods containing salicylates, which is the main chemical in aspirin. Several fruits, especially kiwifruit, contain salicylates.

What to do

• if you have an immediate reaction to a certain food, avoid it in future
• check labels on all tinned and packaged food to make sure they are free from the substances you are allergic to
• if you wish to take something out of your child's diet, discuss it first with your doctor, as it may be important and necessary for healthy growth
• do not use cow's milk formulas
• delay introduction of solids for your child until six months of age
• avoid the major allergy-causing foods in a child's diet until they are two years old. These include cow's milk, wheat, seafood, eggs, soy and peanuts.

Pollens, moulds and fungal spores

Pollens can come from grasses, trees and shrubs. Privet has received publicity as a trigger for asthma but not everyone with asthma is sensitive to it. Grasses and weeds are so widespread and have such a long season that they are the major pollen problem in New Zealand.

Some of the plants to avoid if you are allergy prone:

What should I do?

• avoid mowing lawns and trimming hedges
• replace any tree or shrub in your garden that makes your nose and eyes itch or makes you sneeze and wheeze. Wind-pollinated plants should be avoided - they have light pollen that travels easily
• take extra medicine during the months that you know pollens are likely to make your asthma worse. If you also get hayfever, you may need medicines to treat it
• keep the house as warm and dry as possible to avoid moulds - do not use unflued gas heaters as they release moisture and particulates into the air
• remove mould or mildew from walls, shower curtains, etc. with a fungicide such as very-diluted household bleach
• air clothes and wardrobes regularly.

Occupational triggers

Clues that something at work is affecting your asthma are that your asthma gets worse soon after starting a new job or while you are doing a particular part of your job, or your asthma improves when you are on holiday or at the weekend.

What should I do?

• Before starting a job, consider whether it involves anything that may make your asthma worse
• Identify the cause and take advice on control measures, especially adequate ventilation 
• Avoid any triggers that you can identify. You may need to talk to your boss and see what can be done about avoiding them, or contact the Occupational Safety and Health Service. Your doctor will be able to help you with this
• Ask if you can change to a different area of your work and see if this makes a difference
• If the triggers can't be avoided, discuss with your doctor which medication you can increase. However, if you continue to be exposed to a trigger, then even with increasing medication your asthma is likely to worsen over time
• As a final solution, you may have to change your job.

Some of the most common New Zealand workplace 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.

Individual triggers

Every person with asthma has different triggers. Identifying them is not always easy but it is well worth trying. Using a peak flow meter or recording symptoms when your asthma gets worse will help you identify your triggers.

Pay particular attention to your triggers when your asthma is troublesome, as you will react more to them at this time.

Create your own list of possible asthma triggers. Take this list with you next time you visit your doctor, practice nurse or asthma educator and discuss all that can be done to avoid or deal with them.

Related topics

Also see: Keeping your asthma under control

Original material provided by The Asthma Foundation of New Zealand, 2008. Reviewed by everybody, November 2010.