Wheezing is a whistling sound that can be made while breathing that may be a symptom of an illness or other causes or conditions. If wheezing is accompanied with difficulty breathing, this may be a medical emergency. Wheezing may be a symptom of hayfever, COPD, asthma, acute bronchitis, bronchospasm, swelling in the airways, mucus in the airways, something stuck in the throat or a growth in the airway.

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.

How do I find out what's causing my wheezing?
To determine the cause of your wheezing, your doctor will ask you questions to determine your symptoms and what leads to them. For example, if you have no history of lung disease and you always wheeze after eating a certain food or at a certain time of year, your doctor may suspect that you have a food or respiratory allergy.

Your doctor will listen to your lungs with a stethoscope to hear where the wheezing is and how much wheezing you have. If this is the first time you've been evaluated, your doctor will probably ask you to perform a breathing test (spirometry) and may also arrange a chest X-ray.