Wheeze: Definition & Causes

Instructor: Lynee Carter
Learn about the respiratory symptom called a wheeze. Know how it sounds in the lungs and about the conditions that cause it; the five I's- inflammation, irritation, infection, injury, and illness, and then test your knowledge with a quiz.


Have you ever heard a strange noise when someone was breathing? Did you notice it happened when the person was breathing in or out? Was the sound high-pitch or low-pitch? Perhaps what you were hearing was a wheeze. Let's explore this abnormal lung sound in more detail.


A wheeze is a high-pitch noise that occurs when a person inhales and exhales. This occurs when the airway from the lungs becomes narrow. Air squeezing between the smaller spaces produces a squeaky or whistling sound. It can be heard with or without the special tools the doctor uses to listen to the lungs called a stethoscope. A person who is wheezing may also have chest tightness, difficulty breathing, and repeated coughing.



The main causes of wheezes are the five I's: inflammation, infection, irritation, injury, and illness.


Asthma is a lung disease that produces a wheeze from inflammation. It usually starts in childhood but can occur in adults. Triggers in the environment cause the airways to be sensitive which leads to swelling, increased production of mucous, and spasms of the bronchial tubes. These triggers can include allergens such as pollen, mold, and animal dander, as well as pollutants in the air. Physical activity, emotional stress, and certain medications can also stimulate these effects. When air passes through the narrowed bronchial tubes, wheezes can be heard.


Allergies are the immune system's reaction to foreign invaders that have entered the body. After the body detects substances that can potentially be harmful, it reacts by producing antibodies and other components to fight against them. During the reaction, the airways get very irritated, which narrows the bronchial tubes and leads to wheezes. The symptoms can range from being mild to being a life-threatening condition called anaphylaxis. Substances that can cause this reaction include items like foods, medications, stings from insect bites, and cigarette smoke.


Respiratory tract infections, such as bronchitis and pneumonia, cause the airways to narrow from mucous production. When germs like bacteria, viruses, and fungi enter the lungs, the body secretes mucous that carries substances to fight against them. Its moisture also prevents germs from entering spaces between tissues. The lining of the bronchial tubes becomes thick from the secretions, restricting the amount of air that flows through which produces the wheezes.



In conditions where the lungs are injured the result can lead to wheezes. When a person aspirates, or when a foreign object is breathed into the lungs, it can produce a wheeze when only a small amount of air can pass around it. This can lead to other problems like pneumonia and an obstructed airway. In the condition called emphysema, damage to the air sacs of the lungs disrupts the normal airflow and wheezes can be heard when breathing.

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