Asthma and Allergies Asthma and allergies often go hand-in-hand. Asthma is a disease of the branches of the windpipe (bronchial tubes), which carry air in and out of the lungs. There are several different types of asthma.

Allergic asthma is a type of asthma that is triggered by an allergy (for example, pollen or mold spores). According to the American Academy of Allergy, Asthma and Immunology, half of the 20 million Americans with asthma have allergic asthma.

Air is normally taken into the body through the nose and windpipe and into the bronchial tubes. At the end of the tubes are tiny air sacs called alveoli that deliver fresh air (oxygen) to the blood. The air sacs also collect stale air (carbon dioxide), which is exhaled out of the body. During normal breathing, the bands of muscle surrounding the airways are relaxed and air moves freely. But during an asthma episode or "attack," there are three main changes that stop air from moving freely into the airways:

• The bands of muscle that surround the airways tighten, causing them to narrow in what is called "bronchospasm."
• The lining of the airways becomes swollen, or inflamed.
• The cells that line the airways produce more mucus, which is thicker than normal.

The narrowed airway makes it more difficult for air to move in and out of the lungs. As a result, people with asthma feel they cannot get enough air. All of these changes make breathing difficult.