Classifications and Diagnosis of Asthma

Asthma is classified as either allergic or non-allergic. Both conditions cause airway obstruction and inflammation that is partly reversible by medication. They also produce the same symptoms. The main difference, however, is their cause.

Allergic (extrinsic) asthma: 

An allergic reaction triggers what is known as allergic asthma. Inhaled allergens like dust mites, mold spores, pollen and pet dander may trigger allergic asthma. It is the most common form of asthma, affecting more than 50% of asthma sufferers.

Non-allergic (intrinsic) asthma: 

Non-allergic asthma is not related to allergies and does not involve the immune system. Instead, factors like anxiety, stress, exercise, cold air, dry air, smoke, hyperventilation, viruses and other irritants trigger the disease.

Severity of Asthma

• Mild intermittent: Symptoms occur twice a week or less. Exacerbations are short and the intensity varies. Nighttime symptoms occur twice a month or less.
• Mild persistent: Symptoms occur more than twice a week but less than once a day. Exacerbations may affect daily activities. Nighttime symptoms occur more than twice a month.
• Moderate persistent: Symptoms occur daily. Exacerbations occur twice a week or more. Nighttime symptoms occur more than once a week. 
• Severe persistent: Symptoms are constant and limit the individual's physical activities. Frequent exacerbations disrupt daily activities, and nighttime symptoms occur more than twice a week.  

Predisposition to Asthma

• Infants or young children who wheeze and suffer from viral upper respiratory infections. 
• Individuals with strong allergies. 
• Individuals with a family history of asthma and/or allergy. 
• Perinatal exposure to tobacco smoke and allergens.

Diagnosis

If your doctor feels like you might have asthma, he may have you do some breathing tests. Spirometry is a noninvasive way to evaluate the air capacity of the lungs. Physicians are able to measure the volume of air exhaled before and after a bronchodilator (inhaler) is used.

During this procedure, the spirometer measures the airflow when the patient exhales, comparing lung capacity to the average capacity for the individual's age and racial group. Then the patient inhales medicine from a short-acting bronchodilator. The doctor once again measures the patient's lung capacity. If there is an increase in capacity it is likely that the asthma symptoms can be controlled.

In addition, the physician should have the patient perform some form of physical activity to increase the breathing rate and check for changes in lung capacity (both with and without a bronchodilator).