Asthma is a disease that affects the breathing passages of the lungs (bronchioles). Asthma is caused by chronic (ongoing, long-term) inflammation of these passages. This makes the breathing tubes, or airways, of the person with asthma highly sensitive to various triggers.
When the inflammation is triggered by any number of external and internal factors, the walls of the passages swell, and the openings fill with mucus.
Muscles within the breathing passages contract (bronchospasm), causing even further narrowing of the airways.
This narrowing makes it difficult for air to be breathed out (exhaled) from the lungs.
This resistance to exhaling leads to the typical symptoms of an asthma attack.
Because asthma causes resistance, or obstruction, to exhaled air, it is called an obstructive lung disease. The medical term for such lung conditions is chronic obstructive pulmonary disease or COPD. COPD is actually a group of diseases that includes not only asthma but also chronic bronchitis and emphysema. Some people with asthma do not have COPD. These are the individuals whose lung function returns to normal when they are not having an attack. Others will have a process of lung airway remodeling from chronic, long-standing inflammation, usually untreated. This results in permanent abnormalities of their lung function with symptoms of obstructive lung disease occurring all the time. These people are categorized as having one of the class of diseases known as COPD.
Like any other chronic disease, asthma is a condition you live with every day of your life. You can have an attack any time you are exposed to one of your triggers. Unlike other chronic obstructive lung diseases, asthma is reversible.
Asthma cannot be cured, but it can be controlled.
You have a better chance of controlling your asthma if it is diagnosed early and treatment is begun right away.
With proper treatment, people with asthma can have fewer and less severe attacks.
Without treatment, they will have more frequent and more severe asthma attacks and can even die.
Ongoing persistent airway inflammation can lead to progressive deterioration of lung function and can result in disability and even death.
Asthma is on the rise in the United States and other developed countries. We are not sure exactly why this is, but these factors may contribute.
We grow up as children with less exposure to infection than did our ancestors, which has made our immune systems more sensitive. We spend more and more time indoors, where we are exposed to indoor allergens such as dust and mold. The air we breathe is more polluted than the air most of our ancestors breathed. Our lifestyle has led to our getting less exercise and an epidemic of obesity. There is some evidence to suggest an association between obesity and asthma. Asthma is a very common disease in the United States, where more than 17 million people are affected. A third of these are children. Asthma affects all races and is slightly more common in African Americans than in other races.
Asthma affects all ages, although it is more common in younger people. The frequency and severity of asthma attacks tend to decrease as a person ages.
Asthma is the most common chronic disease of children.