Asthma - symptoms, diagnosis, treatment

Asthma is a long-term condition that affects the airways in the lungs, making it hard for you to breathe. Symptoms include coughing, wheezing and shortness of breath.

Nearly 600,000 people in New Zealand use asthma medication, including one in seven children and one in eight adults.  Asthma is one of the most common causes of admission to hospital for children.  On average, 77 New Zealanders die from asthma each year.

Background

Asthma can start at any age but commonly begins in childhood. Many children grow out of asthma by their teens. Others first develop asthma in adulthood.

Asthma often runs in families and can be associated with allergic conditions such as eczema and hay fever.

New Zealand, along with countries like Australia and Great Britain, has one of the highest rates of asthma in the world. It particularly affects Maori and Pacific peoples. Exposure to certain dusts or chemicals may predispose people in some lines of work to asthma.

Signs and symptoms

With asthma, the airways in the lungs are sensitive to certain irritants or triggers. When exposed to these irritants the small airways in the lungs become swollen, muscles surrounding the airway walls tighten and mucous is produced inside the airways.  This makes breathing difficult and produces the cough, wheeze and shortness of breath that are typical asthma symptoms.

The severity of asthma symptoms varies between individuals. Some experience only mild symptoms while others may have severe attacks that happen suddenly. A severe asthma attack can be life threatening if treatment is not sought immediately.

Common signs and symptoms of asthma include: 

• Coughing – which may worsen at night
• Wheezing
• Chest tightness
• Shortness of breath
• Difficulty speaking (in more severe attacks)
• Blueness around the mouth (in more severe attacks).

Causes

The exact cause of asthma is not fully understood. It is believed to be caused by a combination of genetic (inherited) and environmental factors.  It may be related to modern living, including environmental changes, diet or exposure to some infections.

It is known that most people with asthma constantly have some degree of inflammation in their airways. Their airways are also sensitive to certain irritants, known as triggers. Triggers can cause tightening of already inflamed airways, provoking an asthma attack. Each individual tends to have different asthma triggers, including one or more of the following: 

• Pollens or moulds
• House dust mites
• Animals
• Air pollution
• Certain foods or food additives
• Strong perfumes
• Exercise
• Cigarette smoke
• Some medicines eg: aspirin, non-steroidal anti-inflammatory drugs, beta blockers
• Respiratory infections such as colds and influenza
• Changes in temperature and humidity (eg: sudden exposure to cold dry air)
• Psychological influences eg: extremes of emotion
• Workplace irritants eg: paint and varnish fumes, flour, wood dust. 

Diagnosis

If asthma is suspected, your doctor will discuss your symptoms and ask you about any family history of asthma.  Tests the doctor may use include chest x-rays and measuring how quickly you can exhale air using a peak flow meter. 

Asthma symptoms and signs vary through the day and through the week.  Peak flow meter tests twice daily for a week, or before and after using a reliever inhaler, will show this variation.  The peak flow rate may vary by more than 20% in asthma sufferers. 

Collection of phlegm or measurement of nitric oxide may be used to follow the progress of more complex asthma.

References

Last Reviewed – February 2020