Asthma and allergy
- Allergy plays an important role in asthma, as one of the key factors that can cause asthma and make it worse. There are two main ways in which allergy affects asthma:
- Allergy itself can produce the allergic inflammation in the airways; and
- Exposure to one or more allergens can directly trigger an asthma attack.
- Allergy is very common in Australia and New Zealand, affecting around 20% of people. Asthma is also common, affecting around 10% of people. Around 80% of people with asthma have positive tests to allergens. These can include dust mites, pollen, pets, moulds, drugs, insects, ticks, latex and foods.
- An allergic reaction occurs when a person’s immune system reacts to substances (allergens) that do not affect most people. This leads to inflammation (redness and swelling) and the following conditions:
- Allergic rhinitis (hay fever) affects the nose and eyes and is usually due to inhaled allergens.
- Eczema or urticaria (hives) affect the skin and triggers can include allergens.
- Anaphylaxis (severe allergic reaction) affects the heart and breathing. People with asthma and severe allergies have a higher chance of having fatal anaphylaxis.
- Asthma affects the lungs and triggers can include allergens, infections, exercise, cold air, changes in temperature and cigarette smoke.
- People with asthma experience a narrowing of the airways in the lungs, which obstructs the flow of air into and out of the lungs. This can cause wheezing when breathing out, a persistent cough, difficulty in breathing, shortness of breath, tightness/heaviness in the chest and wheezing/coughing with exercise.
Narrowing of the airways can be reversed using medications. Most people with asthma can therefore lead normal, active lives if they take regular preventer medication.
- In some people, pollen allergens can directly trigger asthma as well as allergic rhinitis. For example, in thunderstorm asthma, pollen granules come into contact with water and release granules. These granules are small enough to be breathed directly into the small airways of the lung and trigger asthma attacks.
- It is important to determine if allergy and specific allergens trigger your asthma and/or make it worse.
If you have asthma and allergies:
- Try to avoid, remove or minimise exposure to confirmed allergens, if possible.
- If you wheeze in Spring or Summer, see your doctor for advice as you may be at risk of thunderstorm asthma.
- Ensure that your allergic rhinitis is treated as well as your asthma, as untreated allergic rhinitis can make asthma more difficult to control.
- Be prepared for emergency treatment of anaphylaxis if you have asthma and severe food and/or insect allergies.
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© ASCIA 2018
ASCIA is the peak professional body of clinical immunology/allergy specialists in Australia and New Zealand
Postal address: PO Box 450 Balgowlah NSW 2093 Australia
This document has been developed and peer reviewed by ASCIA members and is based on expert opinion and the available published literature at the time of review. Information contained in this document is not intended to replace medical advice and any questions regarding a medical diagnosis or treatment should be directed to a medical practitioner. Development of this document is not funded by any commercial sources and is not influenced by commercial organisations.
Content updated November 2018