Asthma

The Facts

Asthma is a chronic lung condition. The airways become inflamed and swollen, causing them to narrow. Air can't move through the lungs as well as it should, making it difficult to breathe. For reasons we do not completely understand, asthma is becoming more common each year, especially in children.

Causes

The cause of asthma is poorly understood, but it may be partly inherited. Everyone's lungs are sensitive to different things such as pollen, air pollution, or strong chemicals. In simple terms, people with asthma have lungs that are more sensitive than average.

There are three processes in the lungs that produce asthma symptoms. First, the inner linings of the airways become inflamed. They swell up, leaving less room for air to pass through. Second, the muscles around the airways can tighten, closing them further. Finally, the airways produce mucus in response to the inflammation, clogging the shrunken tubes.

Asthma is in part an allergic response. It may be triggered by some external substance that particularly irritates your lungs. These triggers are often small protein particles called allergens. Some people are sensitive to more than one trigger. Common allergens include:

• grass, tree, and ragweed pollen
• molds
• house dust mites
• cockroach particles
• animal dander

Other people can get an asthma attack from something they swallow rather than breathe. Examples of these triggers include:

• aspirin* and other anti-inflammatory medications
• preservatives found in some drinks or foods
• nuts or shrimp

While most people develop asthma as children, adults can become asthmatic by being exposed to allergens for a long time. People who work with the following products may be at increased risk:

• foams and paints
• antibiotics
• cotton and flax
• detergents
• grains and cereals
• insulation and packaging materials

Asthma attacks can also be triggered by non-allergic irritants such as:

• viral infections such as the common cold or the flu
• laughing hard, crying, shouting
• smog and smoke
• strong smells (e.g., paint fumes, perfumes, cleaning products)
• suddenly breathing cold air
• vigorous exercise