Asthma is an unpredictable disease but an awareness of the trigger factors that cause an asthma attack can enable patients to live a life that is full and in control.

Certain allergens cause changes deep within the lungs identified first by inflammation of the airways, then by constriction and sensitivity of the airways.

78% of asthmatics have positive reactions to skin tests of common airborne allergens and an allergic response in the airway can be immediate or delayed several hours from exposure, lasting for days or weeks.

As a result, the cause of the delayed response is more difficult to identify, but the effect can be equally or more severe because inflammation of the tissues inside the airways has occurred and has not been treated early.

Common trigger factors include:

• tobacco smoke
• pollution
• dust mites
• molds
• spores
• pollen
• animal dander
• animal urine and feces.

Second-hand smoke, or Environmental Tobacco Smoke (ETS) has been identified as a causative factor in respiratory illnesses, including childhood asthma owing to the harmful substances and irritants identified in the smoke. Because of their immature immune systems, children are at greater risk when exposed to pollutants, because their cells are more vulnerable than adults' cells to chemical alteration.

Tips to reduce allergies

Dust mites and their byproducts are a major allergic factor, living in toys, bedding and other soft furnishings. Ensuring that mattresses and pillows are wrapped with a protective cover, and that bedding is washed weekly will minimize the incidence of asthma attacks due to dust mites. It is also advisable that carpets and rugs be removed from bedrooms where asthmatics sleep.

Wrapping small toys or soft items and freezing them for at least an hour has been shown to kill the dust mites, although the items still requires laundering or vacuuming to remove the dust mites and their byproducts. While mites cannot be totally eradicated, chemicals can be bought over the counter and used to spray onto furnishings to kill and thereby control the mites.

Molds and the spores they produce occur anywhere there is sufficient moisture and humidity for molds to grow such as in bathrooms and basements. Molds reproduce by releasing millions of extremely small spores into the air and like pollen, can stay suspended in the air almost indefinitely.

Some indoor asthma triggers such as dust mites and molds are kept under control by maintaining the humidity of the air at 50% or less. HEPA (high-efficient particulate air) filters remove the smallest particles possible, including pollen, spores, and smoke. All filters should be changed monthly.

When pollen counts are high, patients are advised to stay indoors with doors and windows closed. In some incidences, immunotherapy is recommended to control reactions to allergens such as pollen, animal dander and dust, and your primary care physician can refer them to a specialist in allergy immunotherapy.

By learning new habits and following an action plan for medication, your quality of life can improve by reducing the frequency and duration of asthma attacks.