Guide to Asthma

Appendix 1: Defining Terms

Allergen: a substance that stimulates the immune system to make an allergic reaction. In asthma, this substance is almost always breathed in. Only things of a certain shape and size can function as an allergen. For example, pollen from grasses and trees can act as allergens; ozone, lead paint, and perfumes can not.

Allergy: a specific type of reaction made by the body to certain specific substances that are foreign to it. Some people are genetically programmed to make allergic reactions, others are not. The allergic reaction in asthma serves no known beneficial purpose. It is probably a misdirected application of the part of our immune system designed to fight worms and parasites.

Beta-Agonist: This term describes one family of bronchodilator medicines. All of the members of this family share a common chemical structure. They are all derived from "adrenaline," which is also called "epinephrine."

Bronchial tubes: the system of branching tubes that carry air through the lungs to the tiny air sacks of the lungs (where oxygen can be passed into the blood and carbon dioxide released into the air).

Bronchodilator: a type of medication that acts to open the breathing passages primarily by causing the muscles surrounding the bronchial tubes to relax.

Corticosteroids: a family of medications that are designed to reduce inflammation. They are often referred to as "steroids," and must be distinguished from the muscle-building steroids used by some weight lifters and competitive athletes. Corticosteroids are the anti-inflammatory steroids.

Dust mite: a tiny living animal visible only under the microscope. In its droppings are particles to which many people worldwide make allergic reactions. These mites are found living in dust particles and thrive best in warm and moist climates.

Emphysema: a disease of the lungs almost always caused by long-term cigarette smoking. In emphysema, the lungs lose their normal springiness. As a result, it becomes difficult to exhale air from the lungs -- and in that way emphysema is similar to asthma. However, in many other ways it is different than asthma. Asthma does not turn into emphysema.

Inflammation: Inflammation in asthma refers to swelling and irritation of the bronchial tubes. Many different processes can cause inflammation in the body, as you know from once having had a sunburn or a "skinned" knee. In asthma one generally finds a characteristic allergic type of inflammation.

Leukotrienes: chemicals made in the body as part of allergic reactions. Many chemicals are released in an allergic reaction. Histamine is one that has been known for many years. Leukotrienes are another, very powerful group of such chemicals.

Nebulizer: a machine that takes a liquid form of medicine and converts it into a mist to be breathed in.

Peak flow: a measure of how fast you can blow air out of your lungs. In asthma, your peak flow reflects the extent to which your bronchial tubes are normally open or abnormally narrowed. In that way, it measures how close your breathing is to normal at that moment that you measure it.

Spacer: a hollow chamber into which inhaled medicines can be squirted prior to breathing them in. They are used to help deliver inhaled medicines effectively to the bronchial tubes and to reduce the amount of medicine left behind on the tongue and throat.

Trigger (of asthma): anything that can set off asthma symptoms. Many different categories of things can stimulate asthmatic symptoms, including allergens, inhaled irritants, strong odors, medications, respiratory tract infections, exercise, and strong emotions.