IMPORTANT The information provided is of a general nature and should not be used as a substitute for professional advice. If you think you may suffer from an allergic or other disease that requires attention, you should discuss it with your family doctor. The content of the information articles and all illustrations on this website remains the intellectual property of Dr Raymond Mullins and cannot be reproduced without written permission.

Summary
Asthma is an inflammatory condition affecting the largest to the smallest airways. The result is “irritable” bronchial tubes that contract in response to many irritants like cold air or cigarette smoke.  In some cases scarring of the airways with loss of lung capacity may result with age and duration and severity of asthma. Most patients (~80%) are allergic to inhaled triggers like dust, pollen, mould or pet allergen, and many will have hay fever or eczema as well. There is also a strong genetic component. i.e. allergy often runs in families.

Driving factors for asthma

The major causes of airway inflammation are exposure to allergen (e.g. dust mite, animals, mould spores or pollens), cigarette smoke and infections (the major trigger in infants). Some (~ 10%) will also have symptoms triggered by taking pain-killers like aspirin or herbal remedies like Echinacea or purified pollen extracts like propolis. Others will respond to dietary preservatives like sodium metabisulfite (220, 221, 222) in wine, dried fruits, vinegar, pickled onions, grapes and some fruit salads.  Inhalation of small amounts of sulphur dioxide released may cause a reflex contraction of the bronchial tubes.  Even though MSG is sometimes blamed for triggering asthma, it is an uncommon trigger.

Asthma is not rare

Asthma affects ~ 10 - 20% of the population at some stage during life.  Around 1 in 4 patients with allergic rhinitis (“hay fever”) will experience some degree of asthma and around ¾ of those with asthma have hay fever. People with asthma have “irritable” bronchial tubes.  Mainly the small airways are affected. Muscle around the airways contracts, narrowing the bronchial tubes. This makes it more difficult to breath. Some cough or wheeze, whereas others get puffed or feel unfit.

How is asthma diagnosed?

Suspicion about asthma is usually raised by the presence of symptoms such as cough, wheeze or tightness in the chest. Examination of the chest at the time may reveal “wheezing”, but not always. Monitoring of lung function at home using “peak flow meters” and formal lung function tests may help confirm the diagnosis. Unfortunately, it is often hard to be sure about a diagnosis of asthma in a very young child. Formal lung function testing is often unreliable, and signs such as “wheeze” may be absent or intermittent and some children just cough. Other disorders such as severe hay fever or sinus infection can cause similar symptoms such as cough or wheeze. In some circumstances, response to a trial of medication helps confirm the diagnosis.

Can asthma be prevented?

Early exposure to tobacco smoke in the first few years of life (and even if mum smokes during pregnancy) appears to be a major risk factor for development of asthma. The best advice is for smokers to be banished outside.  Allergen avoidance measures (such as dust mite or pet avoidance) or dietary changes during pregnancy do not seem to reduce the risk of developing asthma, although may reduce symptoms in someone who is already allergic to these triggers.

Allergy and asthma

It is inhaled rather than swallowed allergen that contributes to airway inflammation in asthma. Common allergens include dust mite, grass pollens as well as proteins released by household pets. These become attached to the dust particles within the house, and become such an integral part of the household environment. Allergy tests are useful to identify potential inhaled trigger factors so that an attempt can be made to reduce exposure, but routine testing for food allergens frequently gives misleading or irrelevant results. Sometimes asthma can be triggered by occupational allergic triggers, like exposure to animals, insects, some wood dusts or chemicals or inhaled food allergens in food processing plants.

Asthma mimics

Vocal cord dysfunction may mimic asthma, with tightening of the vocal cords triggering noisy breathing and tight throat. Vocal cord exercises with a speech pathologist can help. Some people experience stress breathing, and relaxed breathing exercises may help.

Assessing asthma severity

Frequency of symptoms.  How often do you cough, wheeze or get breathless?  How often do you wake-up first thing of a morning, last thing at night or in the middle of the night with asthma?

Medication Use.  How often do you need to use your "reliever" medication?  Needing it more than twice per week to control spontaneous asthma is a good reason to consider regular preventative medication.

Exercise Tolerance.  How easy is it to provoke your asthma?  Asthma is likely to be under better control if you can run a marathon than if you get puffed after one flight if stairs.

Peak flows. Peak flow meters give you a rough idea of how your asthma is controlled. The readings obtained are dependent on the degree of effort. Readings can therefore be falsely low if you have bad asthma, are overtired, or in young children who can’t use them properly! Both the level of your peak flow and its variability day to day help to assess your asthma control.  Peak flow monitoring is very useful for assessing asthma severity in adults and older children.  It is less reliable in younger children, where treatment is better based on symptoms. When treatment is first commenced, it if often useful to regularly measure peak flows to get an idea of how good your lung function is to start with, then later compare it with how good it can be with treatment.

Other Measures.  How much time away from school or work have you lost due to asthma?  How often do you wake in the morning feeling tight in the chest?  How often do you get night-time asthma?

When should regular asthma medication be considered?

Needing relievers more than twice per week to control spontaneous asthma is a good reason to consider regular preventative medication.

When asthma attacks are frequent or infrequent but very severe.

When there is significant exercise asthma despite pre-treatment with medication

When lung function is poor but reversible towards normal with medication (even when you feel well).

Pregnancy and asthma

Some increased shortness of breath is normal as the baby takes up some room in the belly. Asthma does not normally worsen in pregnancy. If it does, it is still important to treat the asthma, as uncontrolled asthma is a much greater risk to the baby than any theoretical risk of medication. Indeed, there is little if any evidence that the medications used to treat asthma harm the developing baby in any way. Similarly, these medications cross into breast milk in tiny amounts, but are thought to cause no harm.

Traveling with asthma

Take sufficient medications not only for your expected needs, but extra in case you need to increase the dose if you get worse. Carry your main supplies in your hand luggage. Check that your travel insurance will cover your for “pre-existent ailments”; you may need to fill out extra forms and pay an additional premium.

Last reviewed 29 May 2020