Allergies and asthma

What is asthma?

© Her Majesty the Queen in Right of Canada, represented by the Minister of Health, 2006
With additional information courtesy the Canadian Lung Association.

Description

A chronic, incurable disease that makes it hard to breathe, asthma is one of the most prevalent chronic conditions in Canadian children (ages 4 years and over) and is also a serious problem in adults. Asthma is also an important factor in school absences and hospitalizations in children. At its worst, asthma can be fatal. According to Health Canada, asthma claimed the lives of 287 people in 2003. Alarming as this may be, mortality rates for asthma have fallen since 1990—a fact that coincides with various national efforts to improve control of the disease.

According to the 1998–99 National Population Health Survey (NPHS), asthma affects 2.5 million people—eight percent of adults and twelve percent of children. Asthma imposes a heavy burden on the nation's health care expenditures and reduces the quality of life for individuals with asthma and their families.

In people unaffected by asthma, muscles around airways are relaxed, and as a result, airways can stay open. Breathing is easy because it is unobstructed by mucus or inflammation.

However…

Asthmatics (people affected by asthma) have very sensitive breathing passages. When an asthmatic is around certain things, his or her airways can become red and swollen, becoming inflamed and filling with mucus. This inflammation and mucus buildup narrow breathing passages, making it difficult to breathe. Sometimes, muscles inside the airways tighten or go into spasm, leaving less room for air to pass through. Obviously, the more inflamed and swollen airways become, the more spasms occur.

Risk factors

The exact cause of asthma is unknown, but it appears to be the result of a complex interaction of three factors:

Factor	Examples and known effects
Predisposing factors	e.g. atopy—a tendency to have an allergic reaction to foreign substances
Causal factors	Causal factors such as cat and other animal dander, dust mites, cockroaches, or workplace contaminants may sensitize the airways. People who work in certain occupations may develop work-related asthma from occupational exposure. For instance: Laboratory workers can develop asthma from repeated exposure to lab animals such as rats, mice, or guinea pigs. Spray painters can develop asthma from exposure to isocyanates. Grain handlers can get asthma from grain dust.
Contributing factors	Contributing factors may include cigarette smoke during pregnancy and childhood (second-hand smoke), respiratory infections, and indoor and outdoor air quality. For instance, research has shown that people who live near major highways and other polluted places are more likely to develop asthma. Similarly, children who grow up in homes where a lot of dust and mould are present may be more likely to get asthma. Second-hand smoke is also known to contribute to the development of asthma: children whose mothers smoked during pregnancy and children who grow up in homes in which other family members smoke are more likely to develop asthma.
Family history	Your family history may play a role in the development of asthma. If people in your family have allergic diseases (including asthma), hay fever/allergic rhinits (see Allergies), or eczema, you are at increased risk of having asthma.

Symptoms

Signs and symptoms of asthma differ from one individual to the next. Signs and symptoms are variable: they can change over time, or they may change depending on the situation or on the presence of certain triggers.

The symptoms of asthma include cough, shortness of breath, tightness in the chest, and wheezing. Asthma symptoms and attacks (i.e., episodes of more severe shortness of breath) usually occur after exposure to "triggers." Some of the common triggers are allergens, viral respiratory infections (e.g., a cold), exercise, or exposure to irritant fumes or gases.

When people with asthma are exposed to triggers, the airways in their lungs become inflamed and swollen. As a result, the airways start to narrow and it becomes more difficult to breathe. During some asthma episodes or attacks, the muscles around the airways can also tighten and the airways can produce mucus. These conditions make it even harder to breathe.

Managing asthma

There is no cure for asthma, but there are effective ways for people with asthma to manage their condition. This means preventing the onset of symptoms in response to triggers, and controlling symptoms, once they occur.

For many asthmatics, allergies can exacerbate their asthma. If you have asthma, it's important that you know what you're allergic to and to reduce, eliminate, or avoid allergens in your environment.

People with asthma, their family members and their health care providers all play important roles in co-managing asthma. Successful asthma management depends on the following:

• learning about asthma and how to manage it
• avoiding or controlling triggers such as allergens
• taking the right medicines in the right way at the right time
• ongoing monitoring and follow-up to assess symptoms and response to medication, and to measure lung function
• a personalized asthma management plan

There are two basic types of asthma medicines:

• "Preventer" medications
  decrease the swelling in airways and help prevent asthma episodes. These medicines are inhaled through a device called a "puffer" or inhaler.
• "Reliever" medications
  are used during an asthma episode or attack to reduce symptoms quickly.

With the right asthma management plan, most people with asthma can lead healthy, active lives.

Minimizing the risks

Effective methods to prevent the onset of asthma are still being investigated. It is clear from the development of immune responsiveness that primary prevention of asthma among children likely will focus on the pre-natal, perinatal, and early childhood periods. A number of factors have shown to either increase or decrease the likelihood of fetal sensitization to allergens, but the influence of these factors is complex. Among adults, decreasing occupational sensitizers and irritants is the most promising approach to prevention.

If you or your child is diagnosed with asthma:

• Work closely with your health care provider to develop an asthma management plan:
  • Find out what your specific triggers are, and avoid them whenever possible.
  • Use "preventer" and "reliever" medicines as directed by your health care provider. If you have a puffer, make sure you know how to use it properly.
  • If you find you need "reliever" medicines more often as time goes on, talk to your health care provider about adjusting your asthma management plan.
  • Remember, although asthma symptoms can almost always be controlled, they can also be fatal. Talk to your health care provider about the warning signs that you may need emergency treatment.
• Do research and stay current on news about asthma treatment and management.