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AsthmaAsthma is an inflammatory disease of the lung. This inflammatory process can occur along the entire airway from the nose to the lung. Once the airway becomes swollen and inflamed it becomes narrower, allowing less air through to the lung tissue and causing symptoms such as wheezing, coughing, chest tightness, and trouble breathing. Once considered a minor ailment affecting only a small portion of the population, asthma is now the most common chronic disorder of childhood, and affects an estimated 6.2 million children under the age of 18. The fact that asthma runs in families suggests that genetic factors play an important role in the development of the disease, however, environmental factors also contribute to the disease process. Asthma can be triggered by a wide range of substances called allergens.

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What NIEHS is Doing on Asthma

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Last Reviewed: October 28, 2008