Asthma differs from other obstructive lung diseases in that it is a reversible process. Acute exacerbation's occur, which last from minutes to hours, interspersed with symptom-free periods. When asthma and bronchitis occur together, the obstruction is compounded and is called chronic asthmatic bronchitis. Although asthma is rarely fatal, it affects school attendance, occupational choices, physical activity, and other aspects of our lives. Asthma is often characterized as allergic, idiopathic, non-allergic, or mixed.
Most allergens are airborne and seasonal.
Patients with allergic asthma usually have a family history of allergies and a past medical history of eczema or allergic rhinitis. Exposure to the allergen triggers an asthmatic attack. Idiopathic or non-allergic asthma is not related to specific allergens. Factors such as a common cold, respiratory tract infections, exercise, emotions, and environmental pollutants may trigger an attack. Asthma attacks may become more severe and frequent with time, and can progress to chronic bronchitis or emphysema.