Wheezing

A wheeze is a whistling or musical sound made when air is forced through an airway that has narrowed. You hear it mostly when breathing out, because the airways naturally get smaller on exhaling and a narrowed one narrows further. It is not a diagnosis in itself — it is the sound of obstruction, and the job is to find out what is doing the obstructing.

What it tells you

Whether the wheeze is on both sides or just one matters a great deal.

Both sides, coming and going. This is the pattern of asthma and COPD — widespread narrowing from inflammation and muscle tightening. It responds to inhalers.

One side only, and persistent. A wheeze always heard in the same spot, which does not shift or settle, suggests a single airway narrowed by something specific — a tumour, a stricture, or in children an inhaled object. This needs imaging and often bronchoscopy, and it should not be treated as asthma indefinitely.

The common causes

Asthma. The most frequent cause at any age. Wheeze with cough and chest tightness, worse at night, in cold air, with dust, smoke, pollen or exercise, and better after a reliever inhaler. Confirmed with spirometry rather than assumed.

COPD. In smokers, ex-smokers and people with long exposure to biomass smoke or industrial dust. The wheeze sits on top of a long-standing productive cough and steadily worsening breathlessness.

Chest infection. Bronchitis and pneumonia can cause temporary wheeze while the airway is inflamed. It settles as the infection does.

Allergy. Wheeze that appears in a particular season, in a particular room, or around an animal usually has an allergic trigger. Allergy testing identifies it, and avoiding the trigger does more than any medicine.

Heart failure. Fluid in the lungs produces a wheeze — once called cardiac asthma. It usually comes with breathlessness lying flat and swollen ankles, and the treatment is entirely different, so it must be distinguished.

Acid reflux. Acid reaching the larynx can trigger airway narrowing, often at night when lying down.

Vocal cord dysfunction. Not every whistle comes from the lungs. Narrowing at the vocal cords produces noise heard mostly on breathing in, often with throat tightness, and it does not respond to asthma inhalers. It is treated with breathing and speech techniques, and is commonly misdiagnosed as difficult asthma for years.

An inhaled object. In a small child, a sudden wheeze with coughing and no fever — especially while eating peanuts or playing with small toys — can be something inhaled. This is urgent.

How it is investigated

• Listening carefully, over both sides, in and out. Where the wheeze is and when it occurs narrows things immediately.
• Spirometry with reversibility — the airflow is measured, an inhaler is given, and it is measured again. A clear improvement supports asthma; obstruction that barely changes points to COPD. This single test separates most causes.
• A chest X-ray, particularly for a one-sided or persistent wheeze.
• Allergy testing where the history suggests a trigger.
• A CT scan and bronchoscopy where a fixed, localised narrowing needs to be seen directly.
• An echocardiogram where the heart is a possibility.

Treatment

For asthma, the mainstay is an inhaled preventer taken every day, with a reliever for symptoms — and the technique checked in front of you, because a correctly prescribed inhaler used incorrectly delivers almost nothing. For COPD, long-acting inhalers and pulmonary rehabilitation. For allergy, identification and avoidance of the trigger, with immunotherapy in selected cases. For a fixed narrowing, the treatment is whatever the cause requires, including airway stenting where a major airway is obstructed.

What matters is not reaching for a nebuliser each time, but finding out why the airway narrows and preventing it.