Asthma is a chronic inflammatory disorder of the airways, characterised by reversible airway narrowing with obstruction of airflow to the lungs. Asthma is very common, affecting 1 in 4 children, 1 in 7 teenagers and 1 in 10 adults in Australia (ASCIA, 2010).
Individuals with asthma have hyper-responsive airways, which overreact to stimuli that do not affect other people. During an acute episode of asthma or an “asthma attack” exposure to a trigger causes three main changes to occur within the airways: the lining of the airways become inflamed and swollen, the thin layer of muscle within the wall of the airways constrict and excessive mucous is produced. The airway narrows, and causes individuals to experience one or more of the following symptoms:
– shortness of breath
– difficulty with breathing
– a feeling of tightness in the chest
– a persistent, dry, irritating cough
As mentioned above, asthma attacks occur when the airway is exposed to triggers. Allergens are by far the most common of asthma triggers, with over 80% of asthma sufferers having underlying allergies (ASCIA, 2010). Nevertheless it is important to recognise not all asthma is caused by allergy, and not all allergies lead to asthma.
Allergic asthma is usually caused by the inhalation of such aeroallergens as dust mites, pollens, moulds and animal dander. Food allergies can also stimulate the onset of asthma symptoms in susceptible individuals.
Non-allergic triggers of asthma include irritants in the air (e.g. smoke, chemical fumes, aerosols), respiratory infections and other illnesses, medications (e.g. aspirin and other non-steroidal anti-inflammatory medications), exercise, hormonal changes, food additives, stress and weather conditions (e.g. cold air or extremely dry, wet or windy weather).
Although there is no cure for asthma, with appropriate education, prevention and management the disease can be controlled and asthma sufferers can lead normal, active lives. The likelihood and severity of an acute asthmatic episode can be reduced with awareness and avoidance (where possible) of triggers, compliance with preventer medications and appropriate administration of reliever, symptom control medications (e.g. Ventolin). It is strongly recommended every asthma sufferer develops an Asthma Action Plan, in consultation with their doctor, and this plan is reviewed regularly (ASCIA, 2010).
As there is a close association between asthma and allergies, it is important to determine whether or not an allergy is contributing to asthma symptom exacerbation. Skin prick testing and blood tests for allergen specific antibodies are the primary methods for the identification of allergic sensitivities when asthma is suspected to be allergy-induced (ASCIA, 2010).
Australasian Society of Clinical Immunology and Allergy [ASCIA]. 2010. Asthma and Allergy. ASCIA Education Resources (AER): Patient Information. Accessed July 31, 2015, http://www.allergy.org.au/images/stories/aer/infobulletins/2010pdf/AER_Asthma_and_Allergy.pdf