Wheezing is a high-pitched whistling sound during breathing. It occurs when air flows through narrowed breathing tubes.

Sibilant rhonchi

Wheezing is a sign that a person may be having breathing problems. The sound of wheezing is most obvious when breathing out (exhaling), but may be heard when taking a breath (inhaling).

Wheezing most often comes from the small breathing tubes (bronchial tubes) deep in the chest, but it may be due to a blockage in larger airways or in persons with certain vocal cord problems.

• Asthma
• Breathing a foreign object into the lungs
• Bronchiectasis
• Bronchiolitis
• Bronchitis
• Emphysema (COPD), especially when a respiratory infection is present
• Gastroesophageal reflux disease
• Heart failure (cardiac asthma)
• Insect sting that causes an allergic reaction
• Medications (particularly aspirin)
• Pneumonia
• Smoking
• Viral infection, especially in infants younger than age 2

Schatz M. Asthma in adolescents and adults. In: Rakel P, Bope ET, eds. Conn’s Current Therapy 2008. 60th ed. Philadelphia, Pa: Saunders Elsevier; 2008:chap 189.