Asthma is a disorder of the bronchial airways characterized by periods of bronchospasm. It may be extrinsic (allergic) or intrinsic (non- allergic). Extrinsic asthma usually begins in childhood and the client may be allergic to dust, pollen, insects, mold spores, smoke, medications and foods. Intrinsic asthma is triggered by internal disorders such as common colds, upper respiratory infections or exercise. There are no identified allergies and it occurs over age 35.
It is considered as an inherited disorder that interacts with environmental factors causing the disease. It involves airway inflammation and periodic narrowing of airway lumina (hyperreactivity). Moreover, it is the result of individual response to a wide variety of stimuli and is therefore episodic in nature with fluctuations or worse exacerbation of symptoms.