Asthma and allergens

People with asthma are sensitive to different triggers in their environment. Triggers, or allergens, cause inflammation or swelling in your airways and make your asthma worse.

An allergen is any substance that can bring on an allergic reaction. An allergy is your body’s response to a substance that is normally harmless to most people. If you are allergic to something, then eating it, breathing it or touching it can bring on an allergic reaction.

Most people with asthma are atopic; that is, they have a general tendency to develop allergic diseases. More than 80 per cent of people with asthma find their symptoms get worse when they are exposed to allergens. Managing your asthma includes identifying the triggers that make your symptoms worse and doing all you can to avoid exposure to those triggers.

Many allergens are carried in dust

Minute particles of dust float around in the air you breathe. Depending on the environment you’re in (such as city or country, home or work) and the time of year (such as spring), these dust particles can contain allergens such as:

• House dust mite droppings
• Skin, scales, fur particles (called ‘dander’) from animals
• Insect debris
• Food dust
• Pollens
• Moulds.

It’s not just allergens that can trigger asthma symptoms. Other common triggers include:

• Respiratory infections (common cold)
• Cold, dry air
• Some medications
• Exercise
• Cigarette smoke
• Wood fire smoke
• Perfumes
• Paint
• Chemicals
• Gases.

It is important to know which particular triggers bring on your asthma symptoms. This can be easy with triggers you can see, such as cigarette smoke or animals. However, sometimes it can be tricky. Try to keep a diary of the times and situations when your asthma is worse.

Some general tips to help you in your investigations include:

• If you have asthma all year round, with symptoms worsening a little in autumn, you may be allergic to house dust mite droppings.
• If your asthma symptoms are worse in spring and early summer, you may be allergic to pollens. Your symptoms will depend on what type of pollen you are allergic to.

Allergy testing can help to pinpoint your allergens. The doctor puts small dabs of different allergen solutions, such as pollen extract, along your arm. Then the doctor slightly pricks the skin underneath with a needle. If the skin swells or develops a welt, you are allergic to that substance. Blood tests are available too.

However, these skin and blood tests are not conclusive. Just because your skin and blood reacts to the allergen, doesn’t mean your lungs will too. Think of these tests as a helpful starting point.

Other types of allergic reactions

When a person with asthma is exposed to allergens, their asthma gets worse. Depending on the allergen and where it enters your body, you may experience different symptoms.

Other allergic reactions may include:

• Rhinitis (or hay fever) – sneezing, blocked and runny nose, itchy eyes and throat.
• Eczema – dry, red, itchy skin.
• Hives – skin rashes.

• Your doctor
• Your local chemist
• The Asthma Foundation of Victoria Tel. 1800 645 130 or (03) 9326 7088

• Over 80 per cent of people with asthma find their symptoms worsen when they are exposed to allergens.
• Managing your asthma includes avoiding exposure to your known allergens.

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