Childhood asthma

In Canada, childhood asthma has quadrupled in the last decade. It is one of the most common reasons children are hospitalized or visit emergency departments. No single factor seems to explain why the number of children with asthma is on the rise. However a combination of factors such as better recognition of the disease, increased pollution and possibly changes in lifestyle leading to more time spent indoors, together with genetic predisposition to wheezing may be responsible.

Asthma is an inflammatory disease of the lung’s airways, or bronchial tubes. Symptoms include: recurrent episodes of wheezing, shortness of breath, tightness in the chest and coughing.

Is it asthma?

Asthma is often difficult to diagnose because its symptoms are similar to other conditions. The majority of children with asthma have their first episode before the age of three. Episodes are usually triggered by a viral infection, such as a cold. Children exposed to tobacco smoke have more frequent colds, ear infection and are more likely to wheeze. Studies have shown that two-thirds of young children who wheeze when they have a viral infection will stop wheezing after the age of five. Children who continue to have asthma past the age of five usually have one or more of the following:

  • a family history of asthma or respiratory allergies;
  • allergies or eczema;
  • exposure to tobacco smoke.

Asthma can be classified as episodic, with symptoms appearing for brief periods lasting less than two weeks and no asthma symptoms between the episodes, or persistent, where symptoms appear frequently, up to a few times a week. This does not mean episodic asthma is less serious. Even though asthma symptoms may appear less frequently, they can be as severe as symptoms of persistent asthma.

Episodic asthma occurs most commonly between one and six years of age and has a tendency to disappear as children approach school age. Children with episodic asthma are fine between episodes, which occur mostly when the child has a cold or other respiratory infection.

Children with persistent asthma have symptoms with or without colds. Up to 80 percent of children with persistent asthma are allergic and have close relatives with asthma or allergies. Persistent asthma may begin at an early age but more commonly appears during school age and persists through adolescence and adulthood.

What triggers asthma?

A viral infection is the most common trigger for asthma, especially in younger children, followed by environmental irritants such as tobacco smoke, and allergies. In young children, the most common allergies are to dust mites and furry pets. Children over six years of age may also have outdoor allergies, mostly to pollens and moulds. Breathing cold air, below the freezing point, and strenuous exercise are also triggers for some children. In general, the worst season for asthma is winter because there are more viral infections and because more time is spent indoors, thereby increasing exposure to many sources of allergies.

How can asthma episodes be prevented?

In the case of tobacco smoke, smoking should be done outside the house, and of course, quitting smoking is encouraged.

Children should undergo tests to determine the exact type of allergies they have. If the allergy is to pets, these should be excluded from the indoor living environment or parents should consider finding another home for the animals. To control allergies to dust mites, the use of dust mite impermeable covers for mattresses and pillows is recommended, as well as removing carpets from the child’s bedroom. Bed sheets should be washed in hot water on a weekly basis and objects that attract dust mites or trap animal hair, such as books, stuffed animals and non-washable curtains, should be removed from the bedroom.

What are the current treatments for asthma?

Two main types of medications are available to treat asthma. Relievers, namely quick-acting bronchodilators delivered by an inhaler, are usually used on an as-needed basis. They open up the airways and relieve symptoms. If on a regular basis, the need for a bronchodilator is more frequent than three times a week, then controllers may be a better solution.

Controllers are anti-inflammatory medications that control the swelling in the airways. These are used on a regular, long-term basis. Among these, the most common are inhaled corticosteroids, currently considered by Canadian asthma experts as the first line of treatment for asthma. If regular use of an inhaled corticosteroid is not enough to control asthma, or if the asthma is more severe, other controller medications are added to the inhaled corticosteroids. The preferred “add-on” medications are long-acting bronchodilators, taken by inhaler, followed by leukotriene receptor antagonists, taken as a pill. In the most severe cases, a corticosteroid taken by mouth may be necessary to keep the asthma under control. Short treatments of corticosteroids by mouth are commonly used during acute attacks, which require a visit to the emergency room. Typically, the short treatment is given for five to 10 days.

Children with mild wheezing during a cold may be treated at home with just a bronchodilator given every time the child wheezes or is short of breath. With more severe episodes, when the effect of the bronchodilator lasts less than four hours, or when there is no response to the bronchodilator, the child should be treated in the emergency room. Usually, a short treatment of corticosteroids taken by mouth is started in the emergency room and continued for five days.

Asthma experts are divided in their opinion as to whether inhaled corticosteroids should be used in episodic wheezing. Many doctors, however, recommend using them from the beginning of a cold until the cold ends. This is not the case for persistent forms of asthma, where experts agree inhaled corticosteroids should be used on a regular, long-term basis.

When an asthma treatment is prescribed, your doctor should prepare a personalized action plan with instructions on what to do, how to know if the asthma is not properly controlled and when to seek medical help.

When should I seek further medical help?

If your child is asthmatic, you must promptly consult a doctor when one of the following conditions occurs:

  • Your child is wheezing and the bronchodilator is providing no relief 15 to 20 minutes after use.
  • The wheezing seems to respond to the bronchodilator but only for      a short time.
  • The bronchodilator is needed more often than every four hours.
  • The wheezing seems to respond to the bronchodilator but the asthmatic condition doesn’t start to get better after two to three days. For example, your child has a cold and continues to need the bronchodilator four to six times a day, two to three days after the onset of the wheezing.

Where can I get help?

The Montreal Children’s Hospital Asthma Centre has pediatricians, allergists, respirologists, respiratory therapists and asthma nurses. The Children’s asthma clinic is open six half-days a week (by appointment). The clinic offers medical evaluation, pulmonary function and allergy testing, development of a treatment plan including prescription of medications, and teaching and support for the family. A doctor’s referral is not necessary to make an appointment.

The Quebec Asthma Education Network has named The Montreal Children’s Hospital Asthma Centre an Asthma Education Centre. Physicians or other health professionals refer patients for asthma education to the Centre, which provides parents and children with a better understanding of what asthma is and how to deal with it. The Centre also provides instruction on how to use the various devices and medications, how to assess if the asthma is well controlled, and how to use the prescribed action plan.

There is currently no cure for asthma. However, understanding asthma and controlling the symptoms can help children with asthma lead active and healthy lives.

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09-01-06 Montreal Children's Hospital - SW