Classifying Asthma Severity

Asthma can have different levels of severity. This means how intense or strong it is. The severity of your asthma is based on 2 things:1

A spirometry test given by your doctor to check how well your lungs are working. Your doctor will ask you to blow into a machine called a spirometer. It will show how much air you can exhale. You may be asked to repeat this test after you use an inhaler medicine.

The number and type of asthma symptoms you had during the previous weeks or month. Common asthma symptoms are coughing, wheezing, shortness of breath, and chest tightness. Your doctor may also ask you if you wake up at night with asthma symptoms, if you have been unable to do your regular activities, or if you have missed work or school due to asthma.

Your doctor will create a treatment plan based on how severe your asthma is. Keeping an asthma diary can help you keep track of your recent asthma symptoms and will help you notice if anything has changed. Be sure to bring it the next time you see your doctor.

Types of asthma severity

There are 4 types of asthma severity:1

  • Intermittent
  • Mild persistent
  • Moderate persistent
  • Severe persistent

Asthma severity is based on how often you have asthma symptoms, how often you need to use a rescue inhaler, and your risk of having an asthma attack. More details on each type of severity are below.1

What is intermittent asthma?

Intermittent asthma means that you only have symptoms sometimes. People with intermittent asthma usually have symptoms 2 days a week or less often.1

If you have intermittent asthma, it should not interfere with your normal activity, such as school, work, or hobbies. Your asthma symptoms will rarely wake you up at night. You might use a rescue inhaler 2 days a week or less often. When your doctor tests your lung function with a spirometer, the results are most often normal or near-normal.1

What is mild persistent asthma?

Persistent asthma means that you have symptoms regularly. People with mild persistent asthma have asthma symptoms more than twice a week, but not every day.1

Your daily activities are only slightly limited due to asthma symptoms. If you have mild persistent asthma, you will sometimes wake up at night because of your symptoms. You use rescue medicines more than twice a week, but not every day. Your lung spirometry tests will show near-normal lung function.1

What is moderate persistent asthma?

People with moderate persistent asthma have asthma symptoms every day.1

Some of your daily activities are limited by your asthma. You wake up at least once a week because of asthma symptoms. You use rescue medicines every day to control your asthma symptoms. Your lung spirometry tests will show decreased lung function.1

What is severe persistent asthma?

People with severe persistent asthma have asthma symptoms every day, throughout the day. As a result, your daily activities are extremely limited. You might wake up every night because of your asthma symptoms. You must use rescue medicines several times a day. Your lung spirometry tests will show severely decreased lung function.1

If you have severe asthma, you may need to see a team of specialists in addition to your regular asthma doctor. You might also seek mental health support for asthma, such as seeing a therapist or joining a support group for people with asthma.2

Tell your doctor if you think your asthma is becoming more severe

Only a doctor can tell you which type of asthma you have. If you feel that your symptoms are getting worse or happening more often, let your doctor know right away. They might diagnose you with a different severity of asthma and could need to change your asthma management plan.

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Written by: Sarah O'Brien & Rebecca Finkel | Last Reviewed: February 2021