What is Asthma?

Asthma is a chronic (long-term) condition affecting people of all ages, causing changes to the airways of the lungs.^1,2 There is always some degree of swelling in the lungs with asthma; however, this can worsen, which is called flares (exacerbations).² During a flare, swelling from inflammation, increased thick mucus production, and tightening of the muscles around small airways causes airway narrowing, making it harder to breathe.^1-3 Untreated or poorly controlled asthma can result in scarring of the lungs, called airway remodeling.² When this occurs, asthma treatments may not work as well, and breathing can remain difficult.²

Allergic asthma is the most common type of asthma; it typically starts in childhood, and is often present along with eczema and allergic rhinitis (hay fever).⁴ Airborne allergens that are inhaled help drive the inflammatory process and asthma symptoms.⁴ Allergic asthma often continues on into adulthood, and flares with the change in seasons are more likely.⁴

Rapid Facts on Asthma in Children and Adults

According to the Centers for Disease Control and Prevention (CDC), 1 in 13 people in the US has asthma.³ Rates of asthma in adults and children from 2023 include:⁵
- 8.9% of adults (age 18 and older)
- 6.7% of children (younger than age 18)
Annual number of physician office visits for asthma: 4.9 million (2019)⁵
Number of emergency department visits for asthma (not including chronic obstructive asthma): 939,000 (2021)⁵
Number of deaths: 3,602 (2022)⁵
Low income is linked to asthma prevalence, exacerbations, hospitalizations, and intensive care unit admission⁶
In addition to low income, inequities in wealth, homeownership, level of education, and employment opportunities contribute to asthma disparities⁶
African Americans and Hispanic Americans have higher rates of asthma and are at greater risk of death from asthma-related causes^6,7

References

World Health Organization (WHO). Asthma. May 6, 2024. https://www.who.int/news-room/fact-sheets/detail/asthma
American Lung Association (ALA). What is asthma? Last updated October 23, 2024. https://www.lung.org/lung-health-diseases/lung-disease-lookup/asthma/learn-about-asthma/what-is-asthma
National Institutes of Health (NIH). National Heart, Lung, and Blood Institute (NHLBI). LMBB: What is asthma? March 2020. https://www.nhlbi.nih.gov/health/asthma
Global Initiative for Asthma. Global Strategy for Asthma Management and Prevention, 2024. Updated May, 2024. Available from: https://ginasthma.org/2024-report/.
Centers for Disease Control and Prevention. National Center for Health Statistics. Asthma. https://www.cdc.gov/nchs/fastats/asthma.htm
Grant T, et al. Asthma and the social determinants of health. Ann Allergy Asthma Immunol. 2022;128:5-11. https://www.annallergy.org/article/S1081-1206(21)01132-7/fulltext
NIH/NHLBI. Asthma: causes and triggers. Last updated April 17, 2024. https://www.nhlbi.nih.gov/health/asthma/causes

All URLs accessed March 21, 2025.