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Controlling Severe Asthma

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Asthma Classification: A Complete Guide

Medically Reviewed By Thomas Johnson, PA-C

Asthma classification measures the severity of your condition. It consists of four grades based on how often you experience symptoms and your lung function. Medical professionals use asthma classification to monitor your symptoms and their impact. Your medical team may regularly review your classification because the severity of asthma can change over time.

This article explains asthma classification, including the main criteria, differences between each type, and possible limitations.

Classification of asthma severity

Someone sits in an armchair and uses a red inhaler.
MixMedia/Getty Images

Asthma can be categorized into four grades of severity, based on factors such as:

  • frequency of symptoms
  • how much your symptoms affect your daily life
  • how often you experience nighttime symptoms or symptoms that wake you from sleep
  • how often you need to use rescue or quick-relief inhalers
  • in adults, your forced expiratory volume (FEV1) rate
  • in adults, your forced vital capacity (FEV1/FVC) rate

FEV1 is the amount of air you can forcefully breathe out in 1 second. FVC is the amount of air you can forcefully breathe out after taking the deepest breath you can. Both values are measured in percentages, with a higher percentage suggesting better lung function.

The following is an overview of the asthma grades and some of their main criteria:

Asthma classificationHow often you experience daytime symptomsHow often you experience nighttime symptoms or wake up with symptomsFEV1
Intermittent asthmaa maximum of 2 days a week a maximum of 2 days a month 80% or more
Mild persistent asthmamore than 2 days a week but less than dailymore than 2 days per month but less than weekly80% or more
Moderate persistent asthmaevery day, and flare-ups may last a few daysmore than 1 day a week but less than nightly60–80% without treatment
Severe persistent asthmaseveral times a day or near-constantnightlyless than 60%


To classify your asthma, doctors may:

  • ask about your symptoms and treatment use
  • ask you to keep a diary about your condition, such as when you experience symptoms
  • test lung function, such as a peak expiratory flow test to measure your FEV1/FVC rates

Learn more about lung function tests.

Intermittent asthma

Intermittent asthma causes daytime symptoms up to 2 days a week. It’s the least severe asthma type but still requires care.

Other characteristics of intermittent asthma include:

  • sleep time symptoms 2 days a month or less and not at all for children ages 4 and younger
  • a FEV1/FVC rate of 85% or more
  • little to no impact on your typical activities
  • needing to use a rescue inhaler less than 2 days a week

Read more about intermittent asthma and its symptoms.


Treatment for mild asthma types may include:

  • preventive or daily inhalers
  • quick-relief or rescue inhalers

Learn more about types of asthma medications.

However, your medical team may not prescribe a preventive inhaler for intermittent asthma. Instead, they may recommend a rescue inhaler when needed, such during flare-ups.

Another key approach is managing your asthma triggers. Keeping a symptom diary and working with your doctor to notice patterns and avoid triggers will help.

When to contact a doctor

Contact your doctor for changes in your symptoms, such as:

  • changes in frequency
  • worsening symptoms
  • changes in how your symptoms respond to treatment

These may be a sign that your asthma has changed classifications. A doctor can adjust your treatment plan if needed.

Mild persistent asthma

With mild persistent asthma, you may experience:

  • daytime symptoms that occur more than 2 days a week but less than daily
  • sleep time symptoms that occur 3–4 days a month, or 1–2 days a month in children ages 4 and younger
  • a FEV1 rate of 80% or more
  • a FEV1/FVC rate of 80% or more
  • minor limitations on your daily activities
  • a need to use a rescue inhaler more than 2 days a week but less than daily

See more about mild persistent asthma.


Treatment for mild persistent asthma can involve preventive and rescue inhalers and avoiding triggers.

Complementary treatments for asthma also include:

  • breathing exercises
  • acupuncture
  • regular physical activity

Learn more about asthma triggers and causes.

Moderate persistent asthma

Moderate persistent asthma includes:

  • daytime symptoms or flare-ups that may occur daily or last several days
  • in adults and children, sleep time symptoms that occur more than once a week but less than daily
  • in children ages 4 and younger, sleep time symptoms that occur 3–4 days a month
  • a FEV1 rate of around 60–80% without treatment
  • A FEV1/FVC rate of 75–80%
  • some limitations on daily activities
  • using a rescue inhaler daily

The symptoms of moderate persistent asthma may make sleeping difficult.

Learn more about moderate persistent asthma symptoms and treatment.


Treatment for moderate persistent asthma usually includes preventive and quick-relief inhalers.

Your doctors may also recommend treatments such as:

  • injected medications, such as biologic therapies
  • oral medications, such as:
    • leukotriene receptor antagonists
    • theophylline (Uniphyl, Theochron)
    • steroid tablets

Severe persistent asthma

The following features describe severe persistent asthma:

  • symptoms that occur throughout the day
  • in adults and children, sleep time symptoms that occur 5 days a week or more
  • in children ages 4 and younger, sleep time symptoms that occur more than 1 day a week
  • a FEV1 rate of less than 60%
  • a FEV1/FVC rate of less than 75%
  • severe limitations on daily activities
  • using a rescue inhaler several times a day


If other treatments haven’t helped severe asthma, doctors may recommend bronchial thermoplasty.

Bronchial thermoplasty involves inserting a flexible tube down your throat and into the lungs. The tube delivers heat to the airway muscles, helping them relax and stop asthma symptoms.

Limitations and what to know

The American Academy of Pediatrics notes that asthma management may be more important than severity or classifications.

For example, some asthma cases may initially be more severe but may respond better to treatment, significantly affecting your health and quality of life.

Also, your classification may need regular monitoring and updates because asthma severity can change.

As a result, doctors may consider other factors when reviewing your health and treatment plan, such as how well your treatment is working. Clinicians may use asthma classification as a general guide and only one measure of your condition.


Asthma classifications help measure the severity of your condition. They are based on how often you experience symptoms, how much symptoms affect your life, and your lung function.

There are four main asthma classifications:

  • intermittent asthma
  • mild persistent asthma
  • moderate persistent asthma
  • severe persistent asthma

Medical professionals may use your classification to direct your treatment. Also, your classification may change over time, and doctors may consider other measures when tracking your health.

Medical professionals can explain more about asthma classifications and your treatment.

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Medical Reviewer: Thomas Johnson, PA-C
Last Review Date: 2023 Aug 31
View All Controlling Severe Asthma Articles
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