Asthma and allergens

People with asthma have sensitive airways that can react to different triggers. For some people, ongoing exposure to triggers causes continued inflammation (swelling and redness) and excess mucus 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 other allergic conditions. Although allergies may run in families, individuals may have different allergic responses. Allergic conditions can include:

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

Identifying your triggers#

Asthma is often first recognized 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 the asthma is not well managed.

Identifying and reducing your exposure to allergen triggers may make your 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, then see your doctor for advice.

Your doctor may prescribe medication and give you information on how to reduce your exposure to triggers. Make sure you continue to use your asthma medication as directed and follow your asthma action plan.

Types of asthma triggers#

There are two broad types of triggers:

• Avoidable triggers, including cigarette smoke and many allergens
• Unavoidable triggers, such as air pollution and exercise

Other things that can flare up asthma include irritants (such as perfumes, chemicals, cold or dry air, smoke and paint), certain medicines, dietary triggers, laughter, respiratory tract infections, certain medical conditions, extreme emotions and hormonal changes.

One of the most common triggers for asthma flare-ups is exercise and physical activity. This is one trigger not to avoid if possible, as exercise is an essential part of a healthy lifestyle. Asthma brought on by exercise can usually be managed effectively with the right medicine and the right plan.

Allergens that trigger asthma#

An allergen is any substance that can bring on an allergic reaction. An allergic reaction happens 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 a 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
• mold
• animal dander, especially from pets
• smoke
• certain chemicals
• certain types of thunderstorms (during grass pollen season, these can trigger rare cases of allergic asthma)

Allergy testing for asthma#

There are two main allergy tests that can help to pinpoint your allergens: skin prick tests and serum specific IgE blood tests.

Skin prick tests can be done by your doctor or an allergy specialist. Small amounts of different allergen solutions (such as pollen extract) are applied to the forearm or back with a dropper, and the skin is 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 are blood tests that detect specific IgE antibodies. These antibodies are made by your immune system against allergens such as dust mites, pollens, animal dander, molds and foods.

These skin and blood tests are not conclusive on their own. Just because your skin and blood react to an allergen does not mean your lungs will too. Think of them as a helpful piece of information your doctor can use to assess your overall health and your asthma and allergy needs. Allergy tests can, however, help define the substances you are allergic to and allow a precise approach to managing that trigger. Such tests should only ever be performed under the guidance of a doctor or allergy specialist.

Allergens in the workplace#

Many substances in the workplace may cause asthma to develop, or trigger symptoms in someone who already has asthma. If you have asthma symptoms at work that improve when you are away from work (such as during holidays or on weekends), you may have work-related or occupational asthma.

Occupational asthma can occur in many types of workplaces, but is most commonly reported where people work with flour or grains and isocyanates (chemicals found in paints as hardening agents). Other substances may include wood dust, strong cleaning products, chemicals and animal allergens.

Key points#

• Many people with asthma are atopic, which means they have an increased risk of other allergic conditions.
• 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.
• For someone who is sensitive to an allergen, asthma symptoms may occur when they breathe a substance into their lungs.
• Eventually the airway may narrow and cause breathing difficulties.

Where to get help#