Asthma and allergens

People with asthma have sensitive airways that can react to different triggers in their environment. For some, ongoing exposure to triggers can cause continued inflammation (swelling and redness) and excess mucus production in the airways, making their asthma worse.

Asthma and allergic conditions

Atopy is the genetic tendency to develop allergic conditions. Many people with asthma are atopic, which means they have an increased risk of developing other allergic conditions.

Although allergies may run in families, individuals may have different allergic responses.

Some allergic reactions may include:

• allergic rhinitis (hay fever) – sneezing, blocked and runny nose, itchy eyes and throat
• eczema – dry, red, itchy skin
• hives – skin rashes
• anaphylaxis – a severe form of an allergic reaction that is potentially life-threatening.

Identifying asthma triggers

Asthma is often initially recognised by people when symptoms get worse in response to particular allergens or other triggers.

Everyone's asthma is different, and everyone has different triggers. For most people with asthma, triggers are only a problem when their asthma is not well managed.

Identifying and reducing exposure to your allergen triggers may make your asthma symptoms easier to manage.

If you think you may have an allergy, keep a symptom diary to help identify triggers. Record the times and situations when your asthma is worse and then see your doctor for advice.

Your doctor may prescribe medication and give you information on how to reduce your exposure to allergen triggers. They may also update your asthma action plan.

Make sure you continue to use your asthma medication as directed and follow your asthma action plan.

Types of asthma triggers

There are 2 types of triggers that can flare up someone's asthma:

• Avoidable triggers – including cigarette smoke, allergens, irritants (such as perfumes, chemicals, cold/dry air, smoke and paint) certain medicines and dietary triggers.
• Unavoidable triggers – such as air pollution, exercise, laughter, respiratory tract infections, certain medicines, certain medical conditions, extreme emotions, hormonal changes, pregnancy and sexual activity.

One of the most common triggers for asthma flare-ups is exercise and physical activity. This is one trigger not to avoid if possible. Exercise is an essential part of a healthy lifestyle.

Asthma induced by exercise can usually be treated effectively with the right medicine and the right plan.

The National Asthma Council Australian Asthma Handbook has more information about asthma triggers.

Allergens that trigger asthma

Allergens are any substance that can bring on an allergic reaction. An allergic reaction occurs when your immune system reacts to substances in the environment that are harmless to other people.

If you are allergic to something – eating, inhaling, injecting or touching it can bring on an allergic reaction.

For someone who is sensitive to an allergen, asthma symptoms may occur when they breathe a substance into their lungs. This can make the airway lining swell and the muscles around the airway tighten. Eventually the airway may narrow and cause breathing difficulties.

Common allergic triggers for asthma include:

• house dust mites
• pollen
• mould
• animal dander, especially from pets
• smoke
• chemicals.

Certain types of thunderstorms during grass pollen season can trigger rare allergic asthma.

Allergy testing for asthma

There are 2 main allergy tests that can help to pinpoint your allergens – skin prick tests and serum specific IgE blood tests for a protein found in your body called immunoglobulin.

Skin prick tests

Skin prick tests can be done by your GP or an allergy specialist. Small amounts of different allergen solutions, (such as pollen extract), are applied to the forearm or the back with a dropper, and the skin gently pricked with a sterile lancet. If you have a reaction to the allergen the skin swells or develops a welt.

Serum specific IgE allergy tests

Serum specific IgE allergy tests are blood tests that detect specific IgE antibodies. These antibodies are made by your body’s immune system against allergens (such as dust mites, pollens, animal dander, moulds and foods).

These skin and blood tests are not conclusive in determining asthma triggers. Just because your skin and blood react to an allergen, doesn't mean your lungs will too. Think of these tests as a helpful ingredient for your doctor to use to assess your overall health and asthma and allergy needs.

Allergy tests can however help define the substances you are allergic to and enable a precision approach to managing that trigger.

Tests such as these should only ever be performed under the guidance of a doctor or allergy specialist.

Allergens in the workplace

There are many substances in the workplace that may cause asthma to develop, or trigger asthma symptoms in someone who already has asthma.

If you experience asthma symptoms at work, and these symptoms improve when you are away from work (such as during holidays or on weekends), you may have what is called work-related or occupational asthma.

Occupational asthma can occur in many types of workplaces, but is most commonly reported where people are working with flour or grains and isocyanates (chemicals which are found in paints as hardening agents).

Other substances may include wood dust, strong cleaning products, chemicals, or animal allergens.

Where to get help

• Your GP (doctor)
• Pharmacist 
• Allergy and Anaphylaxis Australia Tel. 1300 728 000
• Asthma Australia Tel. 1800 ASTHMA (278 462)
• National Asthma Council Australia
• The Royal Children's Hospital – videos to help you better understand and manage your child's asthma.