1 Nov 2025

Asthma Causes and Triggers: Understanding and Managing Your Condition

Learn about asthma causes and triggers, how they affect symptoms, and strategies to manage and avoid them. Understand and manage your asthma effectively.

Dr Anna Uridge

General Practitioner at Myhealth Ashmore Plaza

Asthma Causes and Triggers: Understanding and Managing Your Condition

What Causes Asthma?

Asthma is a complex condition, and there isn’t a single clear cause. Research suggests it develops from a combination of genetic and environmental factors. People with a family history of asthma or allergies are more likely to develop the condition.

Early-life exposure to certain environmental factors, such as allergens, smoke, or pollution, may also increase the risk. While these factors may influence the onset, asthma symptoms often appear when triggers cause your airways to react, leading to inflammation and breathing difficulties.

What is an Asthma Trigger?

An asthma trigger is anything that causes your asthma symptoms to flare up or worsen. Triggers do not cause asthma itself but can prompt airway inflammation and constriction, leading to wheezing, coughing, or shortness of breath. Identifying your personal triggers is key to managing asthma effectively, as avoiding or minimising exposure can help prevent flare-ups.

Common triggers range from environmental factors, like pollen or smoke, to lifestyle elements, such as exercise or stress. Understanding your triggers forms the foundation for a personalised asthma action plan.

What are Asthma Symptoms?

Asthma symptoms vary in intensity and frequency, but common signs include:

Shortness of breath or difficulty breathing
Wheezing (a whistling sound when breathing)
Persistent coughing, especially at night or early morning
Chest tightness or discomfort

Symptoms can be mild and occasional or more severe and frequent. Recognising these early can help manage asthma effectively. For a detailed overview, see Asthma Symptoms Brief - MyHealth

Common Asthma Triggers

Allergens

Allergens are substances that trigger an immune response, causing airway inflammation and asthma symptoms. People with allergic asthma often experience worsening symptoms when exposed to specific allergens. Managing these allergens involves understanding what triggers your reactions and taking steps to reduce exposure.

Pollen & Hayfever

Pollen, released by grasses, trees, and weeds, is a major trigger for seasonal allergic asthma, especially during spring and early summer. Hayfever (allergic rhinitis) often occurs alongside asthma, causing sneezing, runny nose, itchy eyes, and nasal congestion. Pollen particles can irritate the airways, leading to coughing, wheezing, and breathlessness. To reduce exposure:

Keep windows closed during high pollen days
Use air purifiers indoors
Shower and change clothes after outdoor activities
Monitor daily pollen counts via apps or websites

Dust Mites

Dust mites are tiny insects found in household dust, bedding, carpets, and upholstered furniture. Their droppings contain proteins that can trigger allergic asthma symptoms. Minimising dust mite exposure can help:

Wash bedding weekly in hot water
Use allergen-proof mattress and pillow covers
Reduce clutter that collects dust

Dust

General household dust contains particles, mould spores, and sometimes dust mites, which can irritate airways and trigger asthma attacks. Regular cleaning, vacuuming with HEPA filters, and keeping floors clear can reduce dust-related flare-ups.

Pet Dander

Proteins in skin flakes, saliva, and urine from cats, dogs, and other furry animals can trigger asthma in sensitive individuals. To manage pet dander:

Keep pets out of bedrooms
Bathe and groom pets regularly
Use HEPA filters to reduce airborne particles

Irritants

Substances that can trigger asthma symptoms without causing an allergic reaction.

Common irritants include strong perfumes, household cleaning chemicals, smoke, and pollution.

These can irritate the airways, leading to coughing, wheezing, and shortness of breath. To minimise exposure:

Use fragrance-free products where possible

Ensure proper ventilation when cleaning

Avoid second-hand smoke and areas with heavy air pollution

Consider wearing a mask when exposure is unavoidable

Weather Conditions

This can influence asthma symptoms. Cold air, high humidity, and rapid temperature shifts can irritate airways and trigger flare-ups. People with asthma may notice worsened symptoms during winter or on very hot and humid days. Preventive strategies include:

Covering your mouth and nose with a scarf in cold weather
Monitoring weather forecasts and staying indoors during extreme conditions
Using a reliever inhaler before outdoor activity if recommended by your doctor

Thunderstorm Asthma

This occurs when pollen and spores are broken into smaller particles by storm conditions, becoming airborne and easily inhaled. This can trigger sudden and severe asthma attacks, especially in people with allergic asthma. To manage thunderstorm asthma:

Stay indoors with windows closed during storms
Keep asthma medication accessible
Follow your asthma action plan closely

Respiratory Infections

Colds, influenza (flu), and other respiratory infections can worsen asthma symptoms by inflaming the airways. People with asthma are more vulnerable to severe symptoms during infections. To reduce risk:

Get annual flu and COVID-19 vaccinations
Wash hands regularly and avoid close contact with sick individuals
Keep up with asthma medications to maintain good control

Physical Activity

Exercise can trigger asthma symptoms, a condition known as exercise-induced asthma (EIA). Symptoms often appear during or shortly after physical activity, including coughing, wheezing, or shortness of breath. Managing EIA involves:

Using a reliever inhaler 10–15 minutes before exercise (as prescribed)
Warming up properly before physical activity
Choosing activities less likely to trigger symptoms, like swimming
Monitoring your symptoms and adjusting intensity as needed

Emotional Stress, Depression, & Anxiety

Strong emotions such as stress, anxiety, and depression can worsen asthma symptoms. Stress triggers the release of hormones that may inflame the airways, while anxiety can cause rapid breathing, making symptoms worse. Depression can also reduce motivation to manage asthma effectively. To reduce these triggers:

Practice relaxation techniques like meditation, deep breathing, or yoga
Seek professional support from counsellors or psychologists
Maintain a regular exercise routine to improve mood and lung function
Develop a support network of family, friends, or asthma support groups

Work-Related Triggers

Certain workplaces expose people to asthma triggers, including dust, chemical fumes, paints, or cleaning agents. Prolonged exposure can lead to work-related asthma symptoms. Strategies to reduce risk include:

Using personal protective equipment (PPE), such as masks or gloves
Ensuring good ventilation in workspaces
Following safety protocols for handling chemicals
Informing supervisors about your asthma and requesting adjustments if necessary

Food-Related Triggers

Some foods can trigger asthma, particularly in individuals with food allergies. Common triggers include nuts, shellfish, eggs, and dairy.

Managing food-related triggers involves:

Reading labels carefully to avoid allergens
Consulting an allergist for testing and advice
Carrying emergency medication, such as an epinephrine auto-injector, if prescribed
Keeping a food diary to track potential triggers and reactions

Smoke related triggers

Smoke from cigarettes, woodfires, and bushfires is a potent asthma trigger. Smoke irritates airways, causing coughing, wheezing, and shortness of breath. To reduce exposure:

Avoid smoking areas and do not smoke indoors

Monitor air quality during bushfire season and stay indoors if levels are poor

Use air purifiers and keep windows closed during smoke events

Follow your asthma action plan and have reliever medication available

Mould

This can trigger asthma attacks, especially in damp environments or after flooding. Mould exposure inflames airways and may worsen allergic asthma. Preventive measures include:

Reducing indoor humidity and using dehumidifiers

Cleaning visible mould with appropriate cleaners

Repairing leaks and water damage promptly

Ventilating areas prone to dampness, such as bathrooms and basements

Other triggers to consider: strong cleaning products, scented candles, aerosols, and air pollution. Awareness and avoidance of these triggers can significantly reduce asthma flare-ups.

Managing and Avoiding Asthma Triggers

Reducing trigger exposure

Minimising exposure to asthma triggers is key to preventing flare-ups. Simple measures, such as staying indoors during thunderstorms, avoiding outdoor activity on high pollen days, or limiting exposure to smoke and strong odours, can make a big difference.

Monitoring air quality, weather forecasts, and pollen alerts helps you plan daily activities safely. Being proactive in avoiding known triggers is one of the most effective ways to keep asthma under control.

Creating a Trigger-Free Environment

Creating a trigger-free environment at home and work can reduce asthma symptoms significantly. Tips include:

Using HEPA air purifiers to reduce dust, pollen, and pet dander

Regular cleaning and vacuuming to minimise dust and mould

Keeping windows closed during high pollen or pollution days

Storing cleaning chemicals, aerosols, and perfumes safely

Ensuring workplaces follow safety measures and provide adequate ventilation.

Asthma Action Plans and Trigger Management

Even with precautions, some triggers cannot be fully avoided. Asthma action plans are essential tools that guide you on how to respond when symptoms appear. They include information on medications, peak flow monitoring, and steps to take during flare-ups. Incorporating trigger management into your plan helps you anticipate risks, adjust activities, and take early action to prevent severe attacks. Reviewing your action plan regularly with your healthcare provider ensures it matches your current triggers and lifestyle.

Medications and Treatments

Medications and treatments play a crucial role in managing asthma triggers. Reliever inhalers provide quick relief of symptoms, while preventer inhalers reduce airway inflammation and sensitivity to triggers. Other treatments, such as allergy medications or biologics, may be recommended for specific triggers.

Following your prescribed medication routine and consulting your healthcare provider ensures optimal protection against asthma flare-ups.

Special Considerations for Children with Asthma

Children with asthma may have unique triggers compared to adults, including respiratory infections, dust mites in bedding, pets, and school-related allergens. Symptoms can appear suddenly and sometimes be harder to recognise. Parents can help by:

Keeping a clean, allergen-free home environment
Monitoring symptoms and triggers closely
Ensuring children take prescribed medications consistently
Communicating with teachers about asthma management at school

Early intervention and trigger awareness can reduce flare-ups and improve a child’s quality of life.

When to see a Doctor

It’s important to discuss asthma triggers with your healthcare provider, especially if symptoms worsen or new triggers appear. Preparing for your appointment can help ensure effective management: