Asthma: Although asthma is more commonly associated with expiratory wheezing, in infants, it can sometimes present with inspiratory wheezing due to the smaller airway size and different respiratory mechanics. Asthma in infants can be triggered by viral infections or allergens.

Viral Croup: This condition is characterized by a barking cough and inspiratory stridor, which can sometimes be perceived as wheezing. It's caused by viral infections, such as parainfluenza virus, and is common in infants and young children.
Bronchiolitis: Caused by respiratory syncytial virus (RSV) and other viruses, bronchiolitis can present with wheezing, although it's more typically associated with expiratory wheezing. Inspiratory wheezing can occur, especially if there's significant airway obstruction.
Gastroesophageal Reflux Disease (GERD): GERD can cause wheezing in infants due to the aspiration of stomach contents into the airways or through a vagally mediated reflex. The wheezing can be inspiratory or expiratory.

Foreign Body Aspiration: This is a medical emergency that can cause sudden onset of inspiratory or expiratory wheezing, depending on the location and nature of the obstruction. It's crucial to consider this diagnosis in any infant with acute onset of respiratory symptoms.
Congenital Heart Disease: Certain congenital heart defects can lead to respiratory symptoms, including wheezing, due to pulmonary congestion or other mechanisms. Early diagnosis is critical for the management and outcome of these conditions.
Pneumonia: Bacterial or viral pneumonia can cause wheezing, among other respiratory symptoms. Identifying pneumonia is crucial due to the need for specific antimicrobial therapy.

Vascular Rings or Slings: These are congenital anomalies of the aortic arch that can compress the trachea or bronchi, leading to respiratory symptoms, including wheezing.
Tracheomalacia: A condition characterized by softening of the tracheal cartilages, which can lead to tracheal collapse and inspiratory wheezing or stridor.
Laryngomalacia: The most common cause of stridor in infants, which can sometimes be mistaken for wheezing. It's due to soft and pliable cartilage of the larynx that collapses inward during inhalation.