Asthma is a disease of the airways, the small tubes which carry air in and out of the lungs.
When exposed to certain asthma triggers (such as cold air, exercise, pollen, and viruses) the sensitive airways react. They can become red and swollen (inflamed) which causes the airway muscles to tighten and produce excess mucus (phlegm). This makes the airways narrow and difficult for a person to breathe.
Common asthma symptoms include:
Asthma is a manageable health condition. Although at the moment there is no cure, with good asthma management and education, people with asthma can lead normal, active lives.
Allergy occurs when a person’s immune system (the body process that protects against disease) reacts to substances in the environment that are usually harmless to most people. These substances are known as allergens. Examples of allergens include house dust mites, pollen, mould, and pet dander. Sensitivity to allergens can often be identified via blood or skin tests.
Other substances such as perfumes, odours, or cigarette smoke can also trigger asthma in some people, but these do not involve a reaction in the person’s immune system. These are called non-allergic irritant triggers, and there are no skin or blood tests for these triggers.
Allergy may run in families. ‘Atopy’ is the genetic or inherited tendency to develop allergic diseases.
When people with allergic tendencies (atopy) are exposed to allergens, they can develop an immune reaction that leads to allergic inflammation (redness and swelling).
This can then cause symptoms in the:
Asthma is a significant health problem in Australia. The number of people with asthma in Australia is high compared to other countries.
Over 2 million Australians have asthma, that is about 1 in 10 people. Of these, about 80% have allergies like hayfever.
If you have asthma that is triggered by allergens, you may have asthma symptoms when you:
It can also be triggered by workplace-related allergens such as flour and grain dust, latex, and animal allergen (e.g. urine, dander).
Because of this close link between asthma and allergy, it can be more difficult to manage your asthma if your allergies are not managed well also.
However, unlike other asthma triggers such as colds and flu, it might be possible to avoid or reduce your exposure to some allergen triggers of your asthma.
Your doctor, nurse practitioner or pharmacist can help work out if allergy plays a role in your asthma (see Allergy tests).
It will then be possible for your doctor to:
It is important to work out which allergens in your environment trigger your asthma. Avoiding or reducing your exposure to these allergens may be an important part of managing your asthma.
Your doctor will ask you questions to identify possible allergic triggers and order or perform allergy tests.
The two main allergy tests are skin prick tests, and blood tests for serum specific IgE* (previously referred to as RAST** tests). These tests identify antibodies to specific allergens.
Sometimes an alternative testing method is used, called scratch testing. It is often used when greater sensitivity in the testing is needed.
Your doctor cannot rely on these test results on their own, so he or she will also consider your test results along with your medical history. Your doctor may refer you to an allergy/immunology specialist for further tests.
Allergy tests should only be performed by a doctor or nurse who has been trained in the procedure, and knows how to interpret the results.
*Immunoglobulin E**RadioAllergoSorbent Test
Skin prick testing is performed at your doctor’s office or medical clinic.
These tests:
Skin prick testing is usually done on the forearm, although it is sometimes done on the back instead. A drop of allergen extract is placed onto a marked area of skin and then a small prick through the drop is made. This allows a small amount of allergen to enter the skin.
If you are allergic to the allergen being tested, a small red lump or wheal will appear after 15–20 minutes. Your doctor will advise you as to what happens next.
Certain medicines such as antihistamines need to be stopped 3-7 days before skin prick testing
Serum specific IgE allergy tests are blood tests.
These tests:
Once your allergic triggers are identified, avoiding or reducing exposure to these allergens may reduce the chance of you having severe asthma attacks and help your lungs to work better.
Allergic diseases such as asthma can be accurately diagnosed and treated using scientifically proven tests like spirometry (for more information see the “Asthma and Lung Function Tests” brochure at nationalasthma.org.au). Scientifically unproven tests, like Vega testing, iridology and kinesiology, are not reliable. They are also not regulated in Australia or New Zealand or currently covered by Medicare.
The Australasian Society of Clinical Immunology and Allergy (ASCIA), the expert health organisation for immune and allergy conditions, advises against using these tests to diagnose conditions or guide treatment. British, American and European allergy and immunology organisations also give the same advice. For more information see the ASCIA website: allergy.org.au.
You should be cautious about accepting the results of such tests for diagnosis and treatment without first discussing them with your doctor.
The most common allergic triggers of asthma are house dust mites, pets, pollen and mould.
Even though complete allergen avoidance does not cure asthma, reducing exposure to your allergen triggers may improve your asthma control and make your asthma symptoms easier to manage. Bear in mind that efforts to avoid or reduce allergen exposure can be costly, time-consuming or impractical.
Efforts to reduce or avoid allergen exposure are best attempted if:
Remember, allergen avoidance or reduction strategies should be used in combination with your recommended medicines and do not replace your doctor’s advice.
While allergy avoidance measures help to reduce exposure to allergen triggers, using your asthma medications as directed is a cheaper and more effective way of dealing with your asthma.
House dust mites are the most common allergic trigger for asthma in Australia. They are microscopic creatures that feed off skin scales, and thrive in temperate and humid climates such as coastal Australia.
How can house dust mite levels be reduced?
If you are allergic to house dust mites you may be advised to take measures to:
The greatest exposure to house dust mites is from your bedding. Ways to reduce house dust mite exposure include:
A hot wash will kill dust mites and remove their allergen. Cold washing followed by hot tumble drying, once items are dry, will kill dust mites. Dry cleaning will similarly kill dust mites, but like cold washing with a hot tumble dry, will not remove the allergen.
Where possible, the person with asthma should leave the room when household cleaning (in particular vacuuming) is being carried out, and for at least 20 minutes afterwards.
Some suggestions include:
While removal of carpets in favour of hard floors is sometimes recommended, this has not been shown to reduce the level of house dust mite exposure in the home. Consider thoroughly and regularly vacuuming using an appropriate appliance first (such as one with a HEPA filter), before considering this more drastic step.
Some modern carpets are manufactured with anti-microbial treatments which may also help.
Reducing humidity in the home is also worth considering - aim for a dry and well-ventilated house with adequate floor and wall insulation. Air conditioners or dehumidifiers (but not evaporative coolers) may be beneficial, particularly in more humid areas as they lower the relative humidity.
Exposure to pets (e.g. cats, dogs, guinea pigs, horses, rabbits, mice, rats) at home or work can trigger asthma in some people.
Cats and dogs are a major source of allergens in the home environment. The allergens come from the sweat glands in cats and salivary glands in dogs. As all cats and dogs have sweat and salivary glands, all breeds have allergens. However, the amount of allergen released can vary between breeds.
As allergens are stuck to the hair and skin of pets, the allergens become airborne when the pet sheds their hair. The allergens can remain airborne for some time.
Cat allergen is especially difficult to remove from houses. It can remain in the house for months after the cat is removed. Cat allergen can be found in places where cats have never lived. For example, it can be carried around on clothing to schools and offices.
The most effective method of allergen avoidance for people with asthma who are allergic to cats or dogs is to not have these pets in the home.
Therefore if your existing pet is causing significant allergy or asthma problems, unfortunately your pet may need to be re-homed with another family.
However, as a first step, your pet should be kept outside most or all of the time, making sure it has a safe and warm home outdoors. If your pet must be kept inside, it should be limited to one area of the house and should not be allowed into the bedroom of the person with asthma.
Other allergen reduction measures include:
Tips for visiting friends with pets:
Allergy to airborne pollen, grains from certain grasses, weeds, and trees is common in people with asthma in Australia. Pollen counts are highest on hot still, or very windy sunny days.
Exposure to pollen:
Completely avoiding pollen can be difficult during the pollen season, but the following steps may help reduce exposure:
Contact your local Asthma Foundation or talk to your local nursery for information on low allergen gardens.
Exposure to indoor and outdoor areas that are damp and have mould can trigger asthma symptoms in some people.
Mould avoidance measures
Air filters and ionizers have been shown to reduce airborne mould, but how this affects asthma control is uncertain.
Measures that may reduce mould exposure include:
Foods are not common triggers for asthma symptoms. They rarely trigger asthma alone, but may trigger asthma as part of a generalised severe food allergy reaction involving other symptoms in the skin and gut. This reaction is known as anaphylaxis and it can be life-threatening. It is rare in adults and uncommon in children.
Food additives and chemicals also rarely trigger asthma. Most reactions to food additives and chemicals are not allergic reactions and cannot be tested by using skin prick tests or serum specific IgE tests.
If foods or food additives are suspected as triggers for your asthma, you may need to be referred to an allergy or immunology specialist for further detailed assessment. If foods are confirmed as triggers, your specialist may recommend you see a dietitian for advice.
It is important to remember that unless you have a food allergy confirmed by your doctor, eliminating certain foods (like dairy or wheat) from your diet is unlikely to improve your asthma.
A written asthma action plan is a set of instructions developed with your doctor (or other health professional like a nurse). It includes your asthma medicine, and how you may need to increase or decrease this depending on your asthma symptoms. A written asthma action plan will also help you to recognise worsening asthma symptoms, and will tell you what to do when this happens.
Your asthma action plan needs to be regularly reviewed by your doctor.
Medicines for people with both asthma and allergies are generally the same as for those who only have asthma i.e. reliever medicine and preventer medicine - both usually in puffers.
There are some preventer medicines thatmay be able to reduce inflammation caused by allergies as well as asthma. Ask your doctor if these medicines might be suitable for you.
If you have untreated allergic rhinitis (hay fever) it can be more difficult to control your asthma symptoms.
Nasal corticosteroid sprays are the most effective long-term medicine for allergic rhinitis. Like preventer medicines for asthma, they need to be used regularly over time. When used in this way, they can improve the control of your asthma and may reduce the chance of you having severe asthma attacks.
Non-sedating antihistamines are also used to treat allergic rhinitis symptoms and are generally safe for people with asthma.
See our brochure Allergic Rhinitis and Hay fever for more information.
Some prescribed and over the counter medications such as aspirin, non-steroidal anti-inflammatory medicines and beta blockers can aggravate asthma.
Natural or complementary therapies such as echinacea, bee pollen/propolis (Royal Jelly), and garlic, can cause life-threatening allergic reactions (such as anaphylaxis) in some people with asthma.
It is important to inform your doctor and pharmacist of any medicines or natural/complementary therapytreatments you are taking.
Specific allergen immunotherapy (also known as desensitisation) is a long-term treatment, usually at least 3 years, which changes the immune system’s response to allergens. It involves taking small but regularly increased amounts of an allergen extract. It can be administered either sublingually, which involves taking a small amount of allergen under the tongue, or with a subcutaneous injection (injection into the fatty layer under the skin).
Immunotherapy should only be started by a doctor with immunotherapy training and be used together with:
Immunotherapy has been shown to improve asthma control in some people with asthma who are allergic to house dust mite, cat and grass pollen allergens. It is also helpful for treating allergic rhinitis/conjunctivitis (hay fever).
Immunotherapy may be suitable for you if:
Immunotherapy cannot be given if you:
Treatment is usually not started in pregnant women, but it can continue during pregnancy if you started using immunotherapy before you became pregnant.
Your doctor will advise you on whether you should undertake immunotherapy.
Immunotherapy should only be initiated, supervised, and regularly monitored by a doctor with appropriate training, such as an allergy specialist (a referral is needed).
You should make sure you discuss the benefits and risks with your allergist/immunologist before you agree to have immunotherapy.
There are certain things that increase the chance of a child developing asthma. For example if you have asthma and/or allergic diseases, your child can have a higher risk of developing asthma and allergic diseases.
Exposure (sensitisation) to environmental allergens has also been associated with childhood asthma. House dust mite avoidance measures may reduce exposure, but it is unlikely that this will prevent wheezing or childhood asthma after your baby’s first year of life.
Based on current evidence, the following measures might assist in preventing asthma from developing, however there is no guarantee:
If your family already has pets it is not necessary to remove them, unless your child develops evidence of pet allergy (as assessed by your doctor or allergy specialist).
A clean, healthy environment is important, but try not to over-sanitise the home with cleaning products. Remember that it is quite common for young children to develop colds which can have similar symptoms to wheeze. Current research suggests that having common childhood infections might actually protect children from developing asthma.
Other prevention measures that have been suggested are contact with farm animals early in life, and the use of probiotics, however both of these measures need further investigation.
There is no evidence that the use of dietary restriction as a prevention measure in the third trimester of pregnancy or while breastfeeding improves asthma.
The Australasian Society of Clinical Immunology and Allergy (ASCIA) advises:
For detailed advice, see ASCIA’s Infant Feeding Advice position statement available at allergy.org.au
Visit the National Asthma Council Australia website to:
Developed by the National Asthma Council Australia in consultation with an expert panel of respiratory and allergy clinicians with a special interest in allergies and asthma.
Supported through funding from the Australian Government Department of Health.
National Asthma Council Australia. Asthma and Allergy: A guide to the management of allergy for those living with asthma. Melbourne. National Asthma Council Australia, 2012.
Although all care has been taken, this brochure is only a general guide; it is not a substitute for individual medical advice/treatment. The National Asthma Council Australia expressly disclaims all responsibility (including negligence) for any loss, damage or personal injury resulting from reliance on the information contained.
© 2012
Plant pollen is well known as a trigger for seasonal allergic rhinitis (hay fever) and seasonal allergic conjunctivitis.
