Classifying Asthma by Severity Level

by Kathi MacNaughton Health Professional

Asthma does not look the same in every person. Although there are common symptoms, what can vary greatly from person to person is the severity and intensity of those symptoms.

For that reason, Asthma experts have devised a ranking system of severity levels. The reasons for this is to help understand the course of the disease in people of different levels and also to devise the best treatment approach for each level.

Asthma's Severity Classifications

To make a diagnosis of a particular level in an asthmatic, the doctor will examine the following factors:

  • Frequency of symptoms

  • Night time awakenings because of symptoms

  • Frequency of use of the rescue inhaler

  • Lung function (FEV1*), as measured by spirometry

  • Interference with regular daily activities of living

*The FEV1 level has to be measured in the doctor's office using a spirometry device.

Each level of severity has commonalities among those factors. Here's what I mean:

Intermittent Asthma

  • Symptoms occur two or less days per week

  • Patient wakes up with asthma symptoms two or less times/month

  • Patient uses rescue inhaler two or less times/week

  • No interference with daily activities

  • FEV1 is more than 80 percent of the predicted during symptoms, but normal between asthma flares

Mild Persistent Asthma

  • Symptoms more often than twice/week

  • Patient awakened with symptoms three to four times/month

  • Uses rescue inhaler more than twice/week, but less than daily

  • Symptoms interfere with daily living to a minor extent

  • FEV1 is more than 80 percent of the predicted level most of the time

Moderate Persistent Asthma

  • Symptoms occur every day

  • Wakes up with symptoms more than once/week but less than daily

  • Uses rescue inhaler daily

  • Symptoms interfere moderately with daily life

  • FEV1 falls between 60 percent to 80 percent of the predicted

Severe Persistent Asthma

  • Symptoms occur throughout every day

  • Wakes up with symptoms most every night

  • Uses rescue inhaler several times a day

  • Symptoms limit daily living severely

  • FEV1 is less than 60 percent of the predicted

If you don't know your current asthma level of severity, talk with your doctor. Asthma management should be directly related to the level you are at. It is referred to a "stepwise approach", which simply means that treatment can be stepped up -- or down -- depending on where you are in terms of severity.

Kathi  MacNaughton
Meet Our Writer
Kathi MacNaughton

Kathi is an experienced consumer health education writer, with a prior career in nursing that spanned more than 30 years — much of it in the field of home health care. Over the past 15 years, she's been an avid contributor for a number of consumer health websites, specializing in asthma, allergy, and COPD. She writes not only as a healthcare professional, but also as a lifelong sufferer of severe allergies and mild asthma, and as a caregiver for her mother with COPD.