Asthma is a chronic, inflammatory lung disease involving recurrent breathing problems. The characteristics of asthma are three airway problems:
Asthma may resemble other respiratory problems, such as emphysema, bronchitis, and lower respiratory infections. It is underdiagnosed--many people with the disease do not know they have it. Sometimes the only symptom is a chronic cough, especially at night, chest tightness, noisy breathing, or wheezing. Some people think they have recurrent bronchitis, since respiratory infections usually settle in the chest in a person predisposed to asthma.
The basic cause of the lung abnormality in asthma is not yet known, although health care professionals have established that it is a special type of inflammation of the airway that leads to:
It is important to know that asthma is not caused by emotional factors as commonly believed years ago. Emotional anxiety and nervous stress can, however, directly affect your immune and respiratory systems and increase asthma symptoms or aggravate an attack. These reactions are considered to be more of an effect than a cause.
A risk factor is anything that may increase a person's chance of developing a disease. It may be an activity, diet, family history, or many other things.
Different diseases have different risk factors. Although these factors can increase a person's risk, they do not necessarily cause the disease. For example, some people with one or more risk factors never develop cancer, while others develop cancer and have no known risk factors.
Knowing your risk factors to any disease can help to guide you into the appropriate actions, including changing behaviors and being clinically monitored for the disease.
The number of people in the U.S. who have asthma is rising. Although the exact cause is unknown, several theories have been proposed as to why. One of the most common is the "hygiene hypothesis," which suggests that living in too clean an environment prevents exposure to germs that stimulate the immune system. Scientists believe that an underutilized immune system may overreact to lesser irritants, inappropriately triggering the release of histamine and other inflammatory substances in the lungs.
Other researchers believe that a variety of factors may be contributing. These include rising obesity rates and increased use of antibiotics.
Although anyone may have an asthma attack, it most commonly occurs in:
Other factors include:
Children most susceptible to asthma attacks include the following:
People with asthma have acute episodes when the air passages in their lungs get narrower, and breathing becomes more difficult. These problems are caused by an oversensitivity of the lungs and airways.
To diagnose asthma and distinguish it from other lung disorders, doctors rely on a combination of medical history, physical examination, and laboratory tests, which may include:
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