Wheezing is a high-pitched whistling sound that occurs during breathing. It occurs when something is blocking the lungs' airways or making them too narrow. Wheezing is most obvious during exhalation, or when you are breathing out; however, wheezing may also be preset during inhalation, or when you are taking a breath, according to MedlinePlus. Several well-known conditions may cause wheezing.
Asthma
Wheezing is a classic symptom of asthma, according to Norman H. Edelman, M.D., chief medical officer for the American Lung Association, or ALA. Asthma is a chronic lung disease that makes breathing difficult for 23 million Americans, including 7 million children, the ALA reports. In asthma, wheezing typically occurs when exhaling. Asthma is not just a condition involving wheezing, however. Coughing, rapid breathing and shortness of breath are also symptoms.
Bronchitis
Bronchitis is another respiratory disease that causes wheezing. Bronchitis is an inflammation of the lining of the airways, inhibiting airflow through the lungs. The result can be wheezing, typically when exhaling. The ALA estimates that 9.9 million Americans were diagnosed with chronic bronchitis in 2009. Cigarette smoking is by far the most common cause of chronic bronchitis.
Emphysema
Emphysema, another lung disease, may be a cause of wheezing, especially when a respiratory infection is present. Emphysema causes the tiny air passages of the lungs to collapse, leading to wheezing, usually when exhaling. Emphysema is most common in long-term smokers and may lead to death, warns Edelman.
Pneumonia
Pneumonia can cause wheezing on exhalation, as well as pain with breathing. Pneumonia is a serious inflammation of the lungs, in which the air sacs fill with pus and other liquids. This narrows the airways, causing wheezing. Pneumonia may be a complication of influenza. Influenza is the most common cause of pneumonia in the elderly and small children, according to Edelman.
Other Causes
A foreign object, such as a peanut, stuck in the airway may cause wheezing, according to Edelman, who adds that this type of wheezing may be particularly high-pitched and vibrating. A tumor may cause the same type of wheezing. MedlinePlus lists other causes of wheezing as gastroesophageal reflux disease, heart failure, allergic reactions to insect stings, respiratory viruses in babies and toddlers, and medications, especially aspirin.
