Asthma

Asthma is a condition characterised by chronic inflammation of the airways. The inflammation can be caused by a number of factors, including viral infections or long-term exposure to a chemical irritant, but is also commonly associated with an immune system reaction to allergens. About 80 per cent of asthma cases in children can be attributed at least in part to allergies, but in adult-onset asthma there is a weaker correlation.

When an asthmatic's airways are chronically inflamed, they become “hypersensitive”. Irritants such as cigarette smoke or even stimuli such as exposure to cold air, stress or laughter can trigger an attack, as can further exposure to allergens. The wheezing, coughing and difficult breathing characteristic of an asthma attack is caused by bronchospasm — the tightening of the bands of muscle surrounding the airways in response to the trigger factor.

Identifying triggers

When asthma is diagnosed, it is important to figure out whether an allergic reaction is involved, and also to identify the trigger factors that set off a reaction. Avoiding or reducing your exposure to the allergens and trigger factors that affect you is the key to controlling asthma symptoms, and may mean you will rely less on medications.

Getting a good diagnosis is crucial. Allergies can be diagnosed with a skin prick test or RAST blood test administered by an experienced doctor or allergy specialist. A skin prick test works by placing drops of a variety of allergen extracts on the forearm and scratching the surface of the skin underneath. If a reaction is observed at the site of the scratch, then an allergy to the particular substance is suspected. The test must be interpreted in conjunction with a thorough symptom history. Keeping a symptom diary of activities undertaken around the time of onset of asthma attacks may be helpful in uncovering trigger factors.

Avoiding triggers

Once you've identified an allergy, it is important to take steps to reduce or eliminate your exposure to the offending substance.

The most common allergens associated with asthma are airborne allergens in the home:

• dust mites
• moulds
• pets
• pollen.