Wheezing occurs when the lower airways become constricted, or as the result of problems with the vocal cords, producing a high-pitched sound during breathing. The causes of wheezing are varied but essentially relate to inflammation and swelling. Histamines that are released in response to something foreign in the body produce a cascade of events that can lead to wheezing and shortness of breath.
Asthma
One of the most common causes of wheezing is asthma. Cough occurs when the airways are inflamed, and wheezing can be audible when breathing in or out. Triggers for asthma include allergens such as perfume, pet dander, air pollution, exercise, anxiety and stress, chemicals and food. Some medications can induce asthma symptoms.
Fluid in the Alveoli
Fluid that fills the air sacs in the lungs, called alveoli, causes wheezing. Wheezing that occurs from fluid in the lungs due to heart failure sometimes is described as cardiac asthma and occurs when the heart muscle is weak. Pneumonia--which can result from viruses, fungus or bacteria that produce infection and inflammation--can lead to the small air sacs in the lower airways filling with fluid when they become inflamed.
Foreign Body in the Airway
Aspirating food or a foreign body into the airway can cause inflammation and wheezing. Children often accidentally inhale small objects into the airway. Symptoms of a partially obstructed airway could be mistaken for asthma, pneumonia or bronchial disease. Adults who have difficulty swallowing from stroke or neuromuscular disease can inhale fluids or food into the airway, producing inflammation and wheezing. Gastroesophageal reflux disease (GERD) can cause aspiration of food that is regurgitated and inhaled into the lungs. Food, fluid, and bile cause irritation that inflame the lungs and can lead to cough and wheezing in some individuals.
Allergic Reaction
An allergic reaction to a bee sting, ant bite, poison ivy, food, medication or other allergen can cause wheezing. Allergy also plays a role in asthma. Sensitivity to specific substances, such as bee venom, causes histamine release that leads to airway swelling, including the throat and tongue. The condition, known as anaphylaxis, can turn into a life-threatening allergic reaction preceded by wheezing then progressing to cessation of breathing and cardiac arrest.
Vocal Cord Dysfunction
Paradoxical movement of the vocal cord can cause wheezing. Some individuals with vocal cord dysfunction--a condition that causes the vocal cords to move during inhalation and stick together--are incorrectly diagnosed with asthma. Stress has been cited as a cause of vocal cord dysfunction. The condition sometimes is difficult to diagnose.
Lung Cancer
In the early stages, lung cancer may not cause any symptoms. As the disease progresses, cough, shortness of breath and wheezing typically occur.
COPD and Emphysema
COPD and emphysema that develop from smoking or long-term exposure to respiratory toxins causes wheezing and cough. Smoking is the leading cause of wheezing associated with emphysema and COPD and occurs from constriction, destruction and inflammation of the airways.
