Differential Diagnosis for a 19-month-old with Cough and No Fever

Single Most Likely Diagnosis

• Viral Upper Respiratory Tract Infection (URTI): This is the most common cause of cough in children, often presenting without fever, especially if the infection is mild or in its later stages. The age of the child and the absence of fever make this a highly plausible diagnosis.

Other Likely Diagnoses

• Asthma: Recurrent cough can be a symptom of asthma, especially in young children where wheezing might not always be present. The diagnosis of asthma in this age group can be challenging but should be considered, especially if there's a family history or if the cough is worsening over time.
• Allergic Rhinitis: Allergies can cause chronic cough due to postnasal drip. In a 19-month-old, this might be an early sign of atopic disease, which includes allergies and potentially asthma.
• Gastroesophageal Reflux Disease (GERD): GERD can cause cough in infants and toddlers due to the reflux of stomach contents into the esophagus, irritating the throat and triggering cough.

Do Not Miss Diagnoses

• Pertussis (Whooping Cough): Although less common due to vaccination, pertussis can still occur, especially in areas with low vaccination rates or in children who have not completed their vaccination series. It's crucial to consider this diagnosis due to its potential severity and the need for public health intervention.
• Foreign Body Aspiration: This is a medical emergency that can present with sudden onset of cough and potentially no fever. It's critical to consider this diagnosis, especially if the cough started abruptly.
• Pneumonia: While fever is often present, pneumonia can occasionally occur without fever, especially in young children. It's essential to consider this diagnosis due to its potential severity.

Rare Diagnoses

• Cystic Fibrosis: This genetic disorder can lead to recurrent respiratory infections and chronic cough. While rare, it's an important consideration in a child with persistent or recurrent respiratory symptoms.
• Primary Ciliary Dyskinesia (Kartagener Syndrome): A rare genetic disorder affecting the cilia, leading to chronic respiratory infections and cough.
• Tuberculosis (TB): Although rare in many parts of the world, TB can present with chronic cough and should be considered, especially if there's a history of exposure or travel to endemic areas.

Each of these diagnoses requires careful consideration of the child's history, physical examination, and potentially further diagnostic testing to determine the underlying cause of the cough.