Asthma is a chronic, inflammatory lung disease involving recurrent breathing problems. It's characterized by three airway problems: obstruction, inflammation, and hyper-responsiveness. Asthma may resemble other respiratory problems such as emphysema, bronchitis, and lower respiratory infections. If asthma is not diagnosed, many people don't know they have it. The cause of the lung abnormality in asthma isn't yet known, although health care professionals have established that it is a special type of inflammation of the airways that leads to contraction of airway muscles, mucus production, and swelling in the airways. It's important to know that asthma is not caused by emotional factors, as was commonly believed years ago. Anxiety and nervous stress can cause fatigue, which may affect the immune system and increase asthma symptoms or aggravate an attack. However, these reactions are considered to be more of an effect than a cause. What happens during an asthma attack? People with asthma have episodes when the smaller air passages in their lungs become narrower and breathing becomes more difficult because asthmatics can't get enough oxygen into their lungs. These problems are caused by an oversensitivity of the lungs and airways, which overreact to certain triggers and become inflamed and clogged. Breathing becomes harder and may hurt, and coughing is common. There also may be a wheezing or whistling sound, which is typical of asthma. Wheezing occurs because muscles that surround the airways tighten, and the inner lining of the airways swells and pushes inward. Membranes that line the airways secrete extra mucus, which can form plugs that further block the air passages. The rush of air through the narrowed airways produces the wheezing sound. Although anyone can have an asthma attack, it most commonly occurs in children. Other factors include having a family history of asthma or a personal medical history of allergies. To diagnose asthma, doctors rely on a combination of your medical history, a physical exam, and lab tests, which may include: Spirometry: The evaluation of lung function with a spirometer. This is one of the simplest, most common pulmonary function tests and may be necessary for the following reasons: To determine how well the lungs receive, hold, and use air To monitor a lung disease To monitor the effectiveness of treatment To determine the severity of a lung disease To determine whether the lung disease is restrictive (decreased airflow) or obstructive (disruption of airflow) Peak flow monitor (PFM): A device used to measure the fastest speed at which a person can blow air out of the lungs. During an asthma or other respiratory flare-up, the large airways in the lungs slowly begin to narrow. This slows the speed of air leaving the lungs and can be measured by a PFM. This measurement is very important in evaluating how well the disease is being controlled. Chest X-rays Blood tests Allergy tests As of yet, there's no cure for asthma. However, it often can be controlled by taking prescription medications that may help prevent or relieve symptoms. Learning ways to manage episodes can also make a difference. People with asthma can learn to identify and avoid the things that trigger an episode, and educate themselves about medications and other asthma management strategies.