Crackling sounds while breathing are suggestive of some conditions in the lower respiratory tract (lungs, bronchi and trachea). Crackling sound while breathing that is audible to naked ears (i.e. without a stethoscope) warrants proper evaluation and treatment because of high risk of having a serious underlying disease condition. The affected person may also experience a sensation of chest rattle while exhaling. Depending upon the cause, the crackling sound may occur in isolation or it might be associated with the other respiratory symptoms.  

Causes of Crackling Sound While Breathing

Some of the most common causes of crackling sound are bronchitis, asthma, pulmonary edema, pneumonia and foreign body in bronchus.

• Bronchitis: Inflammation of the lining of bronchi (the air-carrying passages from the trachea to the lungs) may be acute (new onset bronchitis) or chronic (repeated and long lasting bronchitis). Acute bronchitis might have crackling sounds while breathing even after resolution of the other symptoms of bronchitis.
• Asthma: Narrowing of the air-carrying passages of the lungs results in shortness of breath, coughing and feeling of chest tightness.
• Pneumonia: It is inflammation of the lungs caused by an infection bacteria (commonly), virus or fungi. Presentation and severity are variable. Often, other symptoms of pneumonia like fever, cough, chills, shortness of breath, etc. are also present. Crackling sound while breathing might be the only symptom in some people having a less severe form of pneumonia called "walking pneumonia".
• Pulmonary Edema: Collection of watery fluid in the lungs is referred to as pulmonary edema. Congestive heart failure is one of the most important causes of pulmonary edema. Shortness of breath (which worsens in lying down position) is usually present.
• Foreign Body in Bronchus: Partial blocking of a bronchus can result in chest rattle on exhale. Crackling sounds while breathing might also be there if distal lungs start collapsing (atelectasis).

Treatment of Crackling Sound While Breathing

Treatment would depend upon the disease condition causing this symptom.

• Infectious diseases like pneumonia and bronchitis require a course of antibiotics for complete resolution of symptoms.
• Asthma requires treatment with bronchodilators (as inhalers). Severe asthma may require treatment with other drugs like corticosteroids.
• Pulmonary edema often occurs secondary to some other conditions like heart failure, and treatment is focused on the primary condition resulting in pulmonary edema.
• Foreign body in bronchus requires removal by bronchoscopy. In rare cases, surgery may be needed if bronchoscopy can't remove the blockage.