Medically reviewed by Dr. Vicki Foerster, MD MSc
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1. What is asthma?
In asthma, the lung’s airways are chronically inflamed. Asthma most often starts in childhood but can affect people of all ages. Asthma cannot be prevented and there is no cure.
2. What are the symptoms of asthma?
Symptoms are usually a mixture of wheezing, shortness of breath, chest tightness, and coughing. The cough is often worse at night and in the early morning. Although asthma is common, people are affected differently, and a person’s symptoms and degree of airflow limitation can vary over time.
Symptoms can be triggered by exercise, viral respiratory infections, or environment factors such as exposure to allergens or irritants (for example, pollens, air pollution, house dust mites, tobacco smoke, pets, perfumes, and mold), or changes in the weather (for example, high humidity, thunderstorms, or very cold air).
3. What causes asthma?
An exact cause has not been determined but researchers think there are genetic and environmental causes. These may include:
- A family history – one or both parents with asthma and/or a genetic history of allergies
- Certain respiratory infections during childhood
- Contact with allergens or infections during infancy and early childhood when the immune system is still developing
4. How common is asthma in the U.S.?
On average, about 10% of adults and 8% of children are affected. In 2019, asthma symptoms affected an estimated 25 million Americans, including 20 million adults (age 18+) and 5 million children. Girls and women are affected slightly more often than boys and men.
5. How is asthma diagnosed?
A clear description of symptoms is the first step in an asthma diagnosis. Following this, measuring lung function is important. A lung function test called spirometry may be used for the initial diagnosis. The testing device, a spirometer, measures the maximum amount of air a person can breathe out after taking in a very deep breath. The spirometer can measure airflow before and after a dose of an inhaled asthma medicine to determine how the medication has changed lung function. More complex lung function testing may also be arranged.
6. Types of asthma
There are a number of different types of asthma. For example:
- Adult-onset asthma: This may be caused by exposure to triggers that were avoided in childhood – for example exposure to pets/animals or chemical fumes, or a viral infection that unmasks asthma symptoms.
- Allergic asthma: Not everyone with allergies has asthma, and not everyone with asthma has allergies. However, allergens such as pollen, dust, and pet dander can trigger asthma symptoms and asthma attacks in some people.
- Asthma/chronic obstructive pulmonary disease (COPD): COPD is a collection of lung diseases that cause breathing problems and obstruct airflow. This group of diseases can include asthma. Most people with asthma will not develop COPD, and many people with COPD do not have asthma. However, it’s possible to have both.
- Exercise-induce asthma (exercise-induced bronchoconstriction or EIB): Symptoms develop when airways narrow during physical activity. Many people with asthma have EIB, but not everyone with EIB has asthma. Some people with EIB have won Olympic medals.
- Non-allergic asthma: Rather than being triggered by allergies, symptoms may flare up due to extreme weather, viral illness, or stress.
- Occupational asthma: People with this condition usually work around chemical fumes, dust, or other irritants in the air. People diagnosed with asthma that has another cause may find their symptoms worsen due to airborne irritants at work.
7. How is asthma treated?
A health care provider will work with a patient to create an action plan to recognize and treat asthma symptoms and to determine how to avoid asthma triggers. It is important to know when to seek emergency care (see #6 below). A peak flow meter may be used to track symptoms. A peak flow meter is a handheld device that measures peak expiratory flow rate – how fast a person can blow air out of the lungs.
Asthma medicines are either: (a) medications for long-term control, or (b) quick-relief medications for asthma attacks. If quick-relief medicines are needed more and more, a person may need different treatment. Long-term control medicines decrease the frequency and severity of asthma attacks, but they do not help for asthma attacks.
Examples of medicines most commonly used by people who have asthma:
Long-term controller (usually taken daily to control symptoms and prevent attacks)
- Inhaled corticosteroids: examples are fluticasone (Flovent HFA), budesonide (Pulmicort Flexhaler), mometasone (Asmanex Twisthaler), beclomethasone (Qvar RediHaler), and ciclesonide (Alvesco)
- Combination inhalers: fluticasone and salmeterol (Advair Diskus); budesonide and formoterol (Symbicort); mometasone and formoterol (Dulera); and fluticasone and vilanterol (Breo)
- Leukotriene modifiers: montelukast (Singulair), zafirlukast (Accolate), and zileuton Zyflo)
Quick-relief medicines (usually only taken when an asthma attack occurs)
- Albuterol (ProAir HFA, Ventolin HFA, and others), pirbuterol (Maxair), levalbuterol (Xopenex HFA), or bitolterol (Tornalate)
- Ipratropium (Atrovent HFA)
- Oral steroids (prednisone, prednisolone)
8. Severe asthma attacks
Severe asthma attacks can be life-threatening and it is essential that urgent health care is obtained. Symptoms and signs of a severe asthma attack can include:
- Extreme difficulty breathing
- Fingernails or lips turn gray or blue
- Problems walking or talking
- Neck, chest, or ribs pulled in with each breath
- Nostrils flare when breathing
- Rapid pulse
- Rescue medication does not relieve symptoms
9. What are the goals of asthma treatment?
When asthma is under control, symptoms can be kept to a minimum. For example: (a) symptoms like wheezing or coughing are absent, (b) sleep is improved, (c) it is possible to attend school or work and participate in physical activities, and (d) trips to the hospital are decreased. It is important to stay away from situations that can lead to asthma attacks and to learn the warning signs of an attack.
American Academy of Family Physicians. Asthma. 2020 Sep. Available at: https://familydoctor.org/condition/asthma/
American College of Allergy, Asthma & Immunology. Asthma. 2014. Available at: https://acaai.org/asthma
American Lung Association. Asthma. 2021. Available at: https://www.lung.org/lung-health-diseases/lung-disease-lookup/asthma
Global Initiative for Asthma (GINA). Global strategy for asthma management and prevention. 2021. Available at: https://ginasthma.org/wp-content/uploads/2021/05/GINA-Main-Report-2021-V2-WMS.pdf
Mayo Clinic. Asthma medications: Know your options. 2021. Available at: https://www.mayoclinic.org/diseases-conditions/asthma/in-depth/asthma-medications/art-20045557
U.S. Centers for Disease Control and Prevention (CDC). You can control your asthma. 2012 Jun. Available at: https://www.cdc.gov/asthma/pdfs/asthma_brochure.pdf
U.S. Centers for Disease Control and Prevention (CDC). Most recent national asthma data. 2021 Mar. Available at: https://www.cdc.gov/asthma/most_recent_national_asthma_data.htm