Understanding wheezing: Causes, symptoms and treatment

What is wheezing?

Many people with respiratory allergies know that bouts of wheezing often come with the arrival of hayfever season. Mild wheezing may also accompany respiratory infections such as acute bronchitis and may be experienced by patients in heart failure and by some with emphysema (or chronic obstructive pulmonary disease, COPD). But the characteristic whistling sound of wheezing is a primary symptom of the chronic respiratory disease asthma.

A variety of conventional and alternative remedies can alleviate wheezing. However, you should be regularly monitored by a doctor if you have asthma, severe allergies, chronic bronchitis, emphysema, or COPD. It is often worthwhile to be evaluated at least once by a specialist such as an allergist or a respiratory physician.

What causes wheezing?

The whistling sound that characterises wheezing occurs when air moves through airways that are narrowed, much like the way a whistle or flute makes music. In asthma, this airway narrowing is due to inflammation and spasm of the muscles in the wall of the airways.

Wheezing is usually the result of one of the following health problems:

• Asthma
• Allergic reactions to pollen, chemicals, pet dander, dust, foods, or insect stings
• Acute or chronic bronchitis, which can produce excess mucus in the respiratory tract and cause the lungs' passageways to become blocked

Less commonly, wheezing may also be caused by these health problems:

• Cystic fibrosis
• Obstruction from a foreign body which has been inhaled (such as a coin)
• A tumour in the lungs (rare in non-smokers)
• Congestive heart failure (usually in older adults)

What are the symptoms of wheezing?

The symptoms of wheezing include a musical or whistling sound and laboured breathing, particularly when exhaling; sometimes accompanied by a feeling of tightening in the chest. You can hear wheezing more loudly if you plug your ears and exhale rapidly, or by using a stethoscope held at the neck or over the lungs. On the other hand, stridor is a wheezing sound heard during inhalation, and usually caused by narrowing of the windpipe or vocal cords (in the neck). 

Seek medical advice about wheezing if:

• Wheezing is accompanied by a temperature of 38C (101F) or above. You may have a respiratory infection such as acute bronchitis, or pneumonia.
• Breathing is so difficult that you feel you are suffocating. This can be a sign of a severe asthma episode or an allergic reaction (anaphylaxis); call 999 to get emergency medical help immediately.
• You wheeze frequently and cough up greenish or grey phlegm. You may have chronic bronchitis, emphysema, or COPD.
• You begin wheezing suddenly and cough up frothy pink or white phlegm. This may be a sign of heart failure; get emergency medical help immediately.
• You cough up bloody phlegm, feel breathless or you have a sharp, localised chest pain; this could be a sign of pulmonary embolism.