Asthma is a chronic, usually atopic (allergic) inflammatory condition that affects the lungs and airways. When a person with asthma comes into contact with an asthma trigger, the smooth muscle around the walls of the airways constrict. The lining of the airways also becomes inflamed and starts to swell. Often sticky mucus or phlegm is produced. All these reactions cause the airways to become narrower and irritated, leading to the symptoms of asthma.

Asthma is often poorly controlled and the poorly controlled asthma patient costs the NHS three and a half times as much as a patient who has good control.

• It is estimated that seven out of ten asthmatics suffer attacks that affect their daily life or disturb their sleep.
• Less than half of asthma patients have an annual check up.
• 90% of the deaths attributable to asthma are preventable.¹

Causes of asthma

Most people with asthma do not have trouble breathing every day. However, certain things can trigger a reaction in asthmatic patients. During an asthma attack muscles tighten up and constrict the airways, which results in wheezing, shortness of breath, a cough and often chest tightness. A bronchodilator is needed to relax the muscles that are squeezing the airways and provide quick relief from an attack.

Asthma can start at any age and it is often difficult to know what causes the asthma, but it can be due to:

• Family history of asthma or other allergic conditions including eczema, hay fever or food allergy.
• Many aspects of modern lifestyles, such as changes in housing and diet and a more hygienic environment, may have contributed to the rise in asthma.
• Smoking during pregnancy increases the chance of the child developing asthma.
• Inhaling second-hand smoke increases the chance of asthma developing.
• Irritants in the workplace may lead to a person developing asthma.
• Environmental pollution can make asthma symptoms worse, but it has not been proven to cause asthma.

Symptoms of asthma

• Cough
• Wheeze
• Chest tightness
• Shortness of breath (dyspnoea)
• Variable airflow
• Reversibility when bronchodilators or corticosteroids are used

The patient will have an increased expiratory time, reduced chest expansion and often a persistent cough. Symptoms are commonly worse at night and early in the morning. A child with mild asthma may have an irritating night time cough but be fine during the day.

Peak expiratory flow rate (PEFR)

'Peak flow' is a measure of how well the patient can expel a full inhalation from their lungs. Peak flow is measured using a peak flow meter and the meter readings give an indication of how well the patient's asthma is being controlled.

The patient should monitor their peak flow regularly to determine if their treatment is continuing to be effective. Peak flow monitoring should be more frequent if symptom control is not achieved and the patient is experiencing exacerbations.

Asthma triggers

Although the causes of asthma are not fully understood, asthma is often triggered by a variety of stimuli. Asthmatics often exhibit atopy (a combination of allergic conditions such as rhinitis and eczema) and readily produce immunoglobulin E (IgE) antibodies that become attached to the mast cells of the nasal mucosa and bronchi. Activation of mast cells causes cell degranulation and the release of inflammatory mediators, e.g. histamine, prostaglandins and leukotrienes. These result in localised inflammation and cell damage, the airways then exhibit bronchoconstriction, which in turn obstructs airflow leading to asthma symptoms. A trigger is anything that irritates the airways or stimulates release of the mediators causing the symptoms of asthma to appear. Triggers will be individual to the patient and there will probably be several.

It is very important for every asthmatic to know the triggers of their attacks. Avoidance of triggers will greatly reduce their risk of having trouble breathing.