Asthma

About asthma

Asthma is a chronic (lifetime) disease.

Asthma varies from person to person and can change over time. Many people with asthma can go for long periods of time without any symptoms, for example.

There is no cure for asthma, but asthma can be controlled. Following your asthma action plan is the best way to manage your asthma. You can be symptom-free when your asthma is well-controlled. Keeping your asthma under control is key to living an active lifestyle.

For more information on asthma control see Asthma Control and Management.

What does asthma do to the lungs?

If you have asthma, your airways (breathing tubes) are very sensitive and they over-react when something bothers them. This causes your airways to become:

  • Swollen and filled with mucus – this is called inflammation. The swelling and mucus make the airway wall thicker and your airways narrower. It also makes the airways even more sensitive.
  • Tight – the muscles around your airways also squeeze tight. This makes your airways even narrower.
    • Narrow airways make it harder to breathe and cause other symptoms of asthma. 

Asthma airways

What are the symptoms of asthma?

The common asthma symptoms are cough, wheezing, tightness of chest and breathlessness.

Not everyone has all of the symptoms of asthma. Most people find their symptoms can come and go. They may change at different times of year or even over time. Symptoms also vary depending on your environment, e.g. weather, smoke, exercise. (See triggers for more information on this.) Let’s take a closer look at the symptoms.

Symptom Preschool children Children from 6-12 Teens and adults

Chronic cough– usually a dry cough. It can bring up mucus. Often worse at night or early morning.

Cough with colds generally last up to two weeks.


Cough is chronic (long-lasting) if it lasts longer than 4 weeks.

 

Cough is chronic if it lasts longer than 4 weeks.

Cough is chronic if it lasts longer than 8 weeks.

Wheezing – a high-pitched whistle from the air moving through narrow airways.

Common sign in young children when airways narrow. May hear without stethoscope.

May not be able to hear without a stethoscope unless asthma is out of control.

May not be able to hear without a stethoscope unless asthma is out of control.

Chest tightness – difficulty breathing.

Caregivers may notice rapid breathing.

May find it hard to breathe or experience chest pain or throat tightness.

May find it hard to breathe, experience chest pain or can’t get a deep breath.

Breathlessness – unable to easily catch breath.

Caregivers may notice rapid breathing. Other indications include difficulty with nursing, sleeping, wanting to be carried more or not playing with the same intensity as others his or her age.

May find it difficult to keep up with peers during activities.

May find it difficult to keep up with peers during activities.

 

How is asthma diagnosed?

Many lung diseases have similar symptoms, so it is important to go to your doctor to get a diagnosis. Your healthcare team will talk with you about your symptoms. Your symptom history is the first step in diagnosing asthma. The next step in diagnosing asthma is confirming if your airways are :

  1. obstructed causing the airflow from your lungs to be slower than normal AND
  2. the airflow improves with treatment or changes over time.

Below are the tests used to confirm the obstruction and improvement.

Spirometry – This test measures the speed and the amount of air you can blow out of your lungs. Spirometry is the best way to diagnose asthma, and most people who are 6 years old or older can do it. It can be done at a clinic or pulmonary function lab.

There are two ways to see if the airflow improves with treatment.

  • You will breathe in medication that quickly relaxes tight muscles around your airways. After about 15 minutes, you will repeat the breathing test to see how your airways respond.
  • You will breathe in medication that fights the inflammation (swelling) in your airways. The medication will be taken every day for a few weeks and then you will repeat the test to see how your airways respond.

Peak flow monitoring – This test uses a peak flow meter to measure the top speed you can blow out. It does not measure how much air you can blow out. It can be done at the clinic, office or at home. The ways to confirm an improvement with treatment are based on your age.

  • Children 6-17 years old will breathe in medication that fights the inflammation in their airways for a few weeks and then repeat the test.
  • Adults (18 years old and older) might:
    • Breathe in the medication to relax tight muscles around their airways, wait about 15 minutes and repeat the test to see a response.
    • Breathe in medication that fights inflammation in the airways for a few weeks and repeat the test to see a response.
    • Do the test at home every morning and evening for a couple of weeks. The results are recorded. Your healthcare team will review the results to see if there is a difference. This  would confirm obstruction of flow from your airways.

Challenge test – This test is more complicated as it includes spirometry before and after a challenge to see if your airways will narrow. First a spirometry test is done. Next is the challenge, which will likely be breathing in a small amount of medication. Occasionally the challenge is exercise. After each challenge you repeat the spirometry test. Then you breathe in a medication that quickly relaxes the muscles around your airways and repeat the spirometry again.

Observation for children 1-5 years old – Since children at this age cannot complete the breathing tests, certain steps must be taken to confirm asthma diagnosis. Either a member of the healthcare team documents signs of obstructed airflow, e.g. wheezing AND improvement after treatment or parents report symptoms and improvement with treatment.

What causes asthma?

There is no clear answer to the question ‘What causes asthma?’  There are certain things that may make you more likely to develop asthma. However simply having these does not mean you will have asthma:

  • Family history: If people in your family have asthma
  • Allergies: If you have an allergic disease like hay fever (allergic rhinitis), or eczema, or other allergies
  • Second-hand smoke: Kids whose mothers smoked while pregnant and / or who grew up in a smoky house
  • Childhood lung infections: Some viral infections during the first couple of years of life
  • Air pollution indoors and out: research has shown people who live near major highways and other polluted places are more likely to get asthma. Children who grow up in homes with mould or dust are also more likely to get asthma. 
  • Work environment (occupational asthma): People who work in certain types of jobs
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Page Last Updated: 14/12/2021