Asthma is a complex disease and can be categorized in many ways. The most used classification system is based on asthma severity. The level of severity of asthma determines treatment. The severities of asthma consist of the following categories:

Intermittent asthma is characterized by infrequent symptoms, occurring less than twice a week resulting in the need for a rescue inhaler less than two times per week. Individuals with intermittent asthma experience minimal interference with their regular daily activities and have normal results on pulmonary function tests. They do not require daily asthma medications, relying solely on as-needed medications for symptom relief. Those with intermittent asthma have a low risk of experiencing a severe asthma exacerbation that necessitates a course of oral corticosteroids.

Mild persistent asthma involves symptoms that occur more than twice a week, but not daily, and it necessitates the use of a rescue inhaler more than twice a week but not daily. While it causes minor limitations in normal daily activities, individuals with mild persistent asthma generally have pulmonary function tests that remain at or above 80% of the predicted values. To maintain symptom control, they often require a daily low-level medication, and there is a moderate risk of experiencing 1-2 asthma exacerbations per year that may necessitate a course of oral corticosteroids. Regular monitoring and adherence to an asthma action plan are crucial for managing this level of asthma.

Moderate persistent asthma is characterized by daily symptoms that are not constant throughout the day and the need for a daily rescue inhaler. These symptoms can limit normal daily activities, and pulmonary function testing typically reveals values between 60% and 80% of predicted. Management involves daily medication at a moderate level, often with inhaled corticosteroids, and individuals may be candidates for biologic asthma medications. There is a higher risk of experiencing more than two asthma exacerbations per year, which may be more frequent and severe, necessitating oral corticosteroid treatment. Regular monitoring and a comprehensive treatment plan are essential for managing moderate asthma effectively.

Severe persistent asthma is characterized by symptoms that persist throughout the day, necessitating frequent use of a rescue inhaler. It results in a significant limitation of normal activities and severe impairment of lung function, with pulmonary function testing showing values below 60% of predicted. Management requires high-dose daily medications, often including inhaled corticosteroids and potential eligibility for biologic asthma medications. Those with severe asthma face a high risk of experiencing more than two severe exacerbations annually, which can be both frequent and intense, requiring oral corticosteroid bursts. Close monitoring and collaboration with asthma specialists are essential to effectively manage and improve the quality of life for individuals with severe asthma.

Spirometry is a breathing test that evaluates the function of your lungs by measuring airflow in order to diagnose asthma.

This measures the volume of air in the lungs during different phases of respiratory cycle or with different maneuvers.

Diffusing Capacity of the lungs for carbon monoxide. This is a measurement that assesses the lungs’ ability to transfer gas to and from the inhaled air into the capillaries that line the alveoli in the lungs.

Fractional Exhaled Nitric Oxide (FENO) is a test approved to help assess asthma control. It measures the gas called Nitric Oxide in your breath, which is a marker of inflammation in the lungs.