Asthma: This is the most common cause of rhonchi, which are sounds produced by the turbulent flow of air through partially obstructed airways. Asthma is characterized by recurrent episodes of wheezing, coughing, chest tightness, and shortness of breath.

Chronic Obstructive Pulmonary Disease (COPD): COPD, including chronic bronchitis and emphysema, can cause rhonchi due to chronic inflammation and obstruction of the airways.
Bronchitis: Both acute and chronic bronchitis can lead to rhonchi, as the inflammation of the bronchial tubes can cause obstruction and turbulent airflow.
Pneumonia: Certain types of pneumonia, especially those causing bronchopneumonia or involving the larger airways, can result in rhonchi.

Foreign Body Aspiration: Although less common, aspiration of a foreign body into the airways can cause sudden onset of rhonchi and is a medical emergency, especially in children.
Epiglottitis: This is a severe and potentially life-threatening condition that can cause stridor (a similar but higher-pitched sound than rhonchi) and significant respiratory distress.
Anaphylaxis: Part of the respiratory manifestations of anaphylaxis can include rhonchi due to airway constriction and edema.

Cystic Fibrosis: A genetic disorder that leads to the production of thick, sticky mucus, which can clog the airways and cause rhonchi among other respiratory symptoms.
Bronchiectasis: A condition characterized by damage to the large airways, leading to their widening and scarring, which can result in chronic rhonchi.
Tracheobronchomalacia: A rare condition where the cartilage in the trachea and bronchi is weak or floppy, leading to airway collapse and potential rhonchi.