Non-specific bronchial hyperreactivity: correlation to asthma and modifying factors.

Bronchial hyperreactivity can be induced and modified by allergic and non-allergic factors affecting the airways. Bronchospasm can also be induced by small amounts of many of these agents and by other factors as well. Allergic and non-allergic subjects can be affected. Bronchial obstruction in asthma due to allergic reactions is to a large extent dependent on the degree of nonspecific bronchial reactivity. This can be influenced by different modes of treatment.