Approaches to asthma management.

Allergic asthma is caused by antigen reaction with IgE fixed to mast cells of the bronchi. The reaction causes release of slow-reacting substance of anaphylaxis and histamine, which cause bronchial constriction. Prophylactic treatment includes avoidance of antigens, desensitization and use of cromolyn sodium. The latter appears to impede release of chemical mediators by the mast cell. Although of no value during an acute attack, this agent reduces attacks and reduces the need for other drugs in patients with severe perennial asthma.