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The airways produce a thick mucus and, as the airways narrow, breathing becomes more difficult. These changes in the airway block the flow of air, making it hard to breathe. This narrowing sometimes gets better by itself, but often requires treatment. Asthma causes the airways to become very sensitive and to react to contact with many airborne substances. Severe asthma can be a traumatic, even life-threatening experience.
Incidence; Causes & Development Although asthma occurs at all ages, it is most common in children under 10. There is a 2:1 male:female ratio in children, which equalizes by the age of 30. Mild episodic asthma is due primarily to bronchial smooth muscle contraction whereas moderate to severe sustained asthma is largely due to chronic inflammation of the bronchi with the presence of such white cells as eosinophils, neutrophils and mononuclear cells. People with asthma have airways that are super-sensitive to 'triggers' that do not bother people without asthma.
Treatment & Prevention Some medicines relax the airways while others reduce or prevent the inflammation, swelling and mucus. |
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