The Asthma Center

Classification of Asthma

A representative group of asthma physicians, nurses and researchers has developed a method of classifying asthma into categories of severity in order to help you and your physicians better understand the disease and choose your appropriate treatment. This guide links classification to predetermined treatment regimens. Although this approach has its benefits as a general guide, it is no replacement for an individualized treatment program since you may not do well with the general recommendations of a committee.

Classification of Asthma Severity Before Treatment:
Severity Days with
Nights with
Continual  Frequent  ¡Ü 60% > 30%
Moderate Persistent Daily > 1 time/week 60 - 80% > 30%
 3-6/week > 2 times/month  ¡Ý 80% 20-30%
¡Ü 2/week


¡Ü 2 times/month  ¡Ý 80% < 20%

* PEFR = peak expiratory flow rate measured by peak flow meter
** PEFR variability = difference between AM and PM Peak Expiratory Flow Rates

Once you begin treatment, both symptoms and pulmonary function improve quickly, and you can move into a category of lesser severity. As improvement occurs and/or continues, medications need to be adjusted slowly and carefully to the lowest effective dose. Although symptoms may improve with treatment, you may continue to have a persistent disease which can be documented by decreased pulmonary functions when medications are tapered or discontinued.

Unfortunately, it is possible you are receiving less medication than necessary because you are not complaining of all symptoms, and yet you have ongoing inflammation of the airways. At times, chronic inflammation has little or no symptoms, and yet it may lead to permanent damage to the bronchi when untreated or undertreated for long periods of time.

Although classification of asthma is helpful as a guide, it does not replace individualized treatment. Regular follow-up office visits are the best way to keep asthma under good control while preventing unnecessary flares of asthma and permanent lung damage.