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Asthma & Other Trigger Factors

Genetic predisposition and allergies can cause childhood asthma. Allergies and asthma are related but they are separate conditions.

Majority of children with asthma have allergies. Not everyone who has allergies has asthma, and not all cases of asthma are related to allergies.

A number of different triggers can cause asthma symptoms or start an asthma attack.

Allergens (substances that can cause allergies)

Both indoor and outdoor allergens can cause asthma. Inhaled allergens are the most important allergens for children with asthma. Exposure to even small amounts of airborne allergens can cause asthma symptoms. Repeated exposure may also be a cause of long term inflammation in the airways. The allergens include:

  • Pollens.
  • House dust mites.
  • Moulds.
  • Animal dander.

Animal dander deposits stay in carpets and sofas for many months after removal of the pets from home.

Future exposure to the same allergens will cause the same reaction to occur.

Try to identify possible inhaled allergens that your child is sensitive to. If those allergens are the important triggers for the asthma symptoms, try your best to help your child avoid exposure to the allergens involved.

Some tips to help you avoid some of the most common inhaled allergens:

  • Wash all bedding in hot water once a week.
  • Preferably, do not use carpet on floors.
  • Avoid curtains and drapes.
  • Wipe all surfaces with damp cloth and do not dust.
  • Use washable stuffed animals.
  • Use air conditioners when possible.
  • Avoid sources of outdoor moulds such as wet leaves or garden debris.
  • Limit your child’s outdoor activities during times of high pollen such as early morning.
  • Best, do not to have any pets at home.

If the above measures fail, discuss this with your doctor and he may give anti-allergy medications if necessary.


At least 80% of people with asthma have symptoms triggered by vigorous exercise. The symptoms are more likely to occur in cold, dry air and with sustained effort sports such as sudden burst of running and cross-country runs.

However, with proper management of the child’s asthma, a child can participate in most sports.

Aerobic exercise improves airway function by strengthening the breathing muscles. Swimming is good exercise for asthmatic child and less likely to trigger exercise-induced asthma.

To prevent exercise-induced asthma from occurring, follow the steps below:

  • Take the reliever medication half an hour before exercise.
  • Make sure asthma control is good.
  • Warm-up before exercise.
  • Breath through the nose during exercise.


Viral respiratory infections (cold and flu, chest infection and sinusitis) frequently trigger asthma in most children. These are unavoidable in most children.

For the younger child with frequent severe attack, temporary removal from daycare nurseries may be helpful. It accounts for up to 50% of acute episode of asthma.

Try to avoid crowded public places if possible. Keep your child healthy.


Tobacco smoke contains more than 3, 800 chemical compounds which are bad for health. Smoke damages and irritates the airways.

Passive smoking is harmful to the child in many ways. It:

  • Increases rate of lower respiratory infections.
  • Increases incidence of middle ear effusion.
  • It’s leads to more severe asthma.
  • Is associated with more frequent exacerbations and reduced lung development.

Its avoidance may contribute to prevention of asthma and respiratory morbidity. Advise parents not to smoke in the child presence.


These present in various forms including:

  • Perfumes.
  • Paint fumes.
  • Grain.
  • Flour dust.
  • Saw dust from certain timbers.

If you find out that your child is allergic to any of the substances, avoiding them will help to prevent the asthma symptoms.

Food & Food additives

It is widely believe that food additives and food colouring can cause asthma attacks but documented evidence is difficult to find.

Food allergy occurs in approximately 1% – 2% of childhood population. It is an uncommon trigger for asthma.

Avoiding food triggers can be challenging. Therefore there should not be unnecessary deprivation of food items unless there is a clear link between ingestion of an offending food and precipitation of symptoms.


Some drugs can trigger asthma symptoms. Some of these are:

  • Aspirin.
  • NSAIDS (pain killer).
  • Beta – blockers (medication used in hypertension).
  • Radiological dyes.
  • Royal jelly (concentrated bee-pollen).

The above listed drugs may precipitate attacks and should be avoided as indicated.


Emotional factors such as extreme expressions of laughing, crying, anger, or fear can lead to airway narrowing. Minimal problems will arise with good asthma control and proper asthma treatment.

Weather or temperature changes

Children with asthma are sensitive to sudden temperature and humidity changes. The cold air entering the airways may trigger the asthma attack, especially so during rainy season and from warm to a cold area.

Gastroesophageal reflux

There is evidence that aspiration of stomach acid, or reflux of stomach acid into an inflamed lower oesophagus can lead to airway narrowing to some patient with asthma. Treating the reflux will improve asthma control. If your child has reflux symptoms such as choking, vomiting or feeding difficulties, inform your doctor for further evaluation.

Last reviewed : 26 April 2012
Content Writer : Dr. Norrashidah Hj. Abd Wahab
  : Dr. Nor Mahani Harun
Reviewer : Dr. Norzila bt. Mohamed Zainudin