Conditions guide
Asthma
Asthma is a long-term lung condition in which the airways become inflamed and narrowed, making it harder to breathe at times. Symptoms come and go and can range from mild to life-threatening.
At a Glance
- Asthma affects people of all ages and often begins in childhood.
- The airways are sensitive and can swell, tighten, and produce extra mucus in response to triggers.
- Common symptoms include wheezing, coughing, chest tightness, and shortness of breath.
- Diagnosis often involves lung function tests such as spirometry.
- Treatment generally includes long-term controller medicines and quick-relief (rescue) medicines.
- With good management, most people with asthma can lead active lives.
What It Is
In asthma, the lining of the airways (bronchial tubes) is chronically inflamed and overly sensitive. When exposed to triggers, the muscles around the airways tighten, the lining swells, and extra mucus forms. Together these changes narrow the airways and limit airflow.
Asthma symptoms tend to vary over time. Many people have periods with few symptoms and periods when symptoms flare. A sudden worsening is often called an asthma attack or exacerbation.
There are several patterns of asthma, including allergic asthma, exercise-induced bronchoconstriction, occupational asthma, and asthma that begins in adulthood. Asthma cannot be cured, but it can usually be well controlled.
Common Terminology
- Bronchospasm
- Sudden tightening of the muscles around the airways, which narrows them.
- Wheezing
- A high-pitched whistling sound when breathing, especially breathing out, caused by narrowed airways.
- Spirometry
- A breathing test that measures how much air a person can blow out and how fast.
- FEV1
- Forced expiratory volume in one second, the amount of air exhaled in the first second of a forceful breath, used to assess airway narrowing.
- Peak flow
- A measure of how fast a person can blow air out, which can be checked at home with a small handheld meter.
- Controller medicine
- A medicine used regularly to reduce airway inflammation and prevent symptoms over time.
- Rescue (quick-relief) medicine
- A medicine that works quickly to relax the airway muscles during symptoms.
- Asthma action plan
- A written plan created with a clinician that describes daily management and steps to take when symptoms worsen.
Common Causes and Associations
The exact cause of asthma is not known, but genetic and environmental factors both play a role. Triggers differ from person to person.
- A family history of asthma or allergies increases the likelihood of developing asthma.
- Allergies, eczema, and hay fever (allergic rhinitis) are commonly associated with asthma.
- Allergens such as pollen, dust mites, pet dander, mold, and cockroaches are common triggers.
- Respiratory infections, especially colds and the flu, often trigger flare-ups.
- Tobacco smoke, air pollution, strong odors, and chemical fumes can irritate the airways.
- Exercise, cold or dry air, and strong emotions can bring on symptoms in some people.
- Certain medicines, such as aspirin and other NSAIDs in some people, or beta-blockers, can worsen asthma.
Symptoms and Features
This is a general description, not a diagnostic checklist. Asthma symptoms vary in type and severity, and other conditions can cause similar symptoms.
- Wheezing, especially when breathing out.
- Coughing, which is often worse at night, early in the morning, or with exercise.
- Chest tightness or a feeling of pressure in the chest.
- Shortness of breath.
- Symptoms that come and go, often worsening with colds, allergens, or exercise.
- Waking at night because of coughing or breathing difficulty.
Tests and Evaluation
Asthma is diagnosed using a combination of medical history, a physical exam, and lung function tests.
- Spirometry measures airflow, and is often repeated after using a bronchodilator to see whether airflow improves.
- Peak flow monitoring can show how breathing varies over days or weeks.
- Bronchial challenge tests, such as methacholine challenge, may be used when spirometry is normal but asthma is still suspected.
- Fractional exhaled nitric oxide (FeNO) testing can help show airway inflammation.
- Allergy testing by skin prick or blood test may identify allergic triggers.
- A chest X-ray or other tests may be used to rule out other causes of symptoms.
Treatment Overview
Asthma treatment is generally adjusted in steps based on how well symptoms are controlled, and is planned with a clinician.
- Inhaled corticosteroids are common long-term controller medicines that reduce airway inflammation.
- Short-acting bronchodilators, such as albuterol, are used as quick-relief medicines to open the airways during symptoms.
- Some treatment plans use combination inhalers containing a corticosteroid and a long-acting bronchodilator, sometimes for both daily control and symptom relief.
- Other options include leukotriene modifiers and, for severe asthma, biologic medicines that target specific parts of the immune response.
- Good inhaler technique, sometimes with a spacer, helps medicine reach the lungs.
- Avoiding or reducing exposure to known triggers is an important part of management.
- A written asthma action plan helps people recognize worsening symptoms and know which steps their care team has outlined.
When Professional Care May Be Discussed
Severe shortness of breath, difficulty speaking in full sentences, blue or gray lips or fingernails, or symptoms that do not improve with quick-relief medicine are generally treated as a medical emergency; in the US, people are advised to call 911.
- Recurring cough, wheezing, or shortness of breath is commonly evaluated by a healthcare professional.
- Needing quick-relief medicine more often than usual is generally seen as a sign that asthma is not well controlled.
- Nighttime awakenings from asthma symptoms are typically discussed with a clinician.
- Side effects or difficulty using an inhaler are often reviewed with a clinician or pharmacist.
- Asthma control is usually reviewed regularly, and after any flare-up or emergency visit.
Questions to Ask a Healthcare Professional
General questions people often find useful to bring to an appointment:
- What tests are generally used to confirm asthma?
- What is the difference between controller and quick-relief medicines?
- How can inhaler technique be checked and improved?
- Which triggers are most commonly linked with asthma flare-ups?
- What does an asthma action plan usually include?
- What signs suggest asthma is not well controlled?
- How is exercise-induced asthma generally managed?
Sources
This guide was written in plain language from the following authoritative references.
Last updated October 8, 2026. FreeDoc guides are general educational information and are not a substitute for care from a qualified professional.