Viral upper respiratory tract infection (URTI): This is the most common cause of cough in children, especially at the age of 1. Viruses such as rhinovirus, coronavirus, and respiratory syncytial virus (RSV) are frequently implicated.

Asthma: Although less common in infants, asthma can present with cough, especially if it's chronic or recurrent. It's often associated with wheezing and shortness of breath.
Allergic rhinitis: Allergies to dust mites, pollen, or pet dander can cause chronic cough in children.
Gastroesophageal reflux disease (GERD): Stomach acid reflux can irritate the throat and cause coughing, especially after feeding or when lying down.
Pneumonia: Bacterial or viral pneumonia can cause cough, fever, and difficulty breathing.

Pertussis (Whooping Cough): A highly contagious bacterial infection that can be severe in young children, characterized by a distinctive whooping sound during coughing.
Foreign body aspiration: Objects like nuts, coins, or small toys can be inhaled and cause sudden onset of coughing and choking.
Congenital heart disease: Certain heart defects can lead to coughing due to pulmonary congestion or edema.
Cystic fibrosis: A genetic disorder that affects the lungs and digestive system, causing chronic cough, wheezing, and recurrent respiratory infections.

Tuberculosis (TB): A bacterial infection that can cause chronic cough, fever, and weight loss, although it's less common in young children.
Ciliary dyskinesia: A rare genetic disorder that affects the movement of cilia in the respiratory tract, leading to chronic cough and recurrent infections.
Interstitial lung disease: A group of rare disorders that affect the lung tissue, causing cough, shortness of breath, and difficulty breathing.
Anatomical abnormalities: Conditions like tracheoesophageal fistula or laryngomalacia can cause coughing and respiratory symptoms in infants.