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What Causes Asthma?

Asthma image

Since asthma has a genetic origin and is a disease you are born with, passed down from generation to generation, the question isn’t really “What causes asthma?” but rather “What causes asthma symptoms to appear?”

People with asthma have inflamed airways that are super-sensitive to things that do not bother other people. These things are called triggers. Although asthma triggers vary from person to person based on if you have allergic asthma or non-allergic asthma, some of the most common include:

⇒ Substances that cause allergies, called allergens, such as dust mites, pollens, molds, pet dander, and even cockroach droppings. In many people with asthma, the same substances that cause allergy symptoms can also trigger an asthma episode. These allergens may be things that you inhale, such as pollen or dust, or things that you eat, such as shellfish. It is best to avoid or limit your exposure to known allergens in order to prevent asthma symptoms.

⇒ Irritants in the air, including smoke from cigarettes, wood fires, or charcoal grills. Also, strong fumes or odors and irritants in the environment can bring on an asthma episode. These may include paint fumes, smog, aerosol sprays, and even perfume or scented soaps. Although people are not actually allergic to these particles, they can aggravate inflamed, sensitive airways.

In many people with asthma, the same substances that cause allergy symptoms can also trigger an asthma episode.

Today, most people are aware that smoking can lead to cancer and heart disease. What you may not be aware of, though, is that smoking is also a risk factor for asthma in children and a common trigger of asthma symptoms for people of all ages who have asthma. It may seem obvious that people with asthma should not smoke, but they should also avoid the smoke from others’ cigarettes. This second-hand smoke, or passive smoking, can trigger asthma symptoms in people with the disease.

⇒ Respiratory infections such as colds, flu, sore throats, and sinus infections. These are the number one asthma trigger in children.

⇒ Exercise and other activities that make you breathe harder. Exercise – especially in cold air – is a frequent asthma trigger. A form of asthma called exercise-induced asthma is triggered by physical activity. Symptoms of this kind of asthma may not appear until after several minutes of sustained exercise. (When symptoms appear sooner than this, it usually means that the person needs to adjust his or her treatment.)

The kinds of physical activities that can bring on asthma symptoms include not only exercise but also laughing, crying, holding your breath, and hyperventilating (rapid, shallow breathing). The symptoms of exercise-induced asthma usually go away within a few hours. With proper treatment, a person with exercise-induced asthma does not need to limit his or her overall physical activity.

⇒ Weather, such as dry wind or cold air, or sudden changes in weather can sometimes bring on an asthma episode.

⇒ Expressing strong emotions like anger, fear, or excitement. When you experience strong emotions, your breathing changes – even if you don’t have asthma. When a person with asthma laughs, yells, or cries hard, natural airway changes may cause wheezing or other asthma symptoms.

⇒ Some medications, like aspirin, can also be related to episodes in adults who are sensitive to aspirin.

People with asthma react in various ways to these factors. Some react to only a few; others to many. Some people get asthma symptoms only when they are exposed to more than one factor or trigger at the same time. Others have more severe episodes in response to multiple factors or triggers. In addition, asthma episodes do not always occur right after a person is exposed to a trigger. Depending on the type of trigger and how sensitive a person is to it, asthma episodes may be delayed.

When a person with asthma laughs, yells, or cries hard, natural airway changes may cause wheezing or other asthma symptoms.

Each case of asthma is unique. If you have asthma, it is important to keep track of the factors or triggers that provoke your asthma episodes. Because the symptoms do not always occur right after exposure, this may take a bit of detective work.

The Role of Heredity
Like baldness, height, and eye color, the capacity to have asthma is an inherited characteristic. Yet, although you may be born with the genetic capability to have asthma, asthma symptoms do not automatically appear. Scientists do not know for certain why some people get asthma and others do not. However, researchers have found that certain traits make it more likely that a person will develop asthma.


Source: Asthma and Allergy Foundation of America,

This article was originally published in Coping® with Allergies & Asthma magazine, Spring/Summer 2009.