Differential Diagnosis for a Non-Immunized 6-year-old with Persistent Dry Cough Followed by Vomiting

• Single Most Likely Diagnosis

  • Pertussis (Whooping Cough): This is the most likely diagnosis given the symptoms of persistent dry cough followed by vomiting in a non-immunized child. Pertussis is a highly contagious respiratory illness caused by Bordetella pertussis, and its classic presentation includes a paroxysmal cough that can be followed by vomiting.

• Other Likely Diagnoses

  • Viral gastroenteritis: Although the primary symptom is a dry cough, the vomiting could suggest a gastrointestinal involvement, possibly due to a viral infection. However, the cough would be more prominent in this case.
  • Asthma: Could present with cough and vomiting if the cough is severe enough to induce vomiting, especially in a child with no previous diagnosis of asthma and without a clear allergic or environmental trigger.
  • Bronchiolitis: Typically affects younger children but can present with cough and vomiting due to respiratory distress.

• Do Not Miss Diagnoses

  • Pneumonia: Although pneumonia typically presents with fever and productive cough, atypical presentations, especially in young children, can include dry cough and vomiting. It's crucial to consider this diagnosis due to the potential severity of pneumonia.
  • Foreign body aspiration: Can cause sudden onset of cough and potentially vomiting if the object obstructs the airway sufficiently to induce gagging or if there's associated respiratory distress.
  • Tuberculosis (TB): Less common but critical to consider, especially if the child has been exposed to someone with TB. TB can present with chronic cough, among other symptoms.

• Rare Diagnoses

  • Cystic fibrosis: A genetic disorder that can lead to recurrent respiratory infections and could potentially present with chronic cough and gastrointestinal symptoms due to malabsorption.
  • Congenital anomalies of the respiratory tract: Such as tracheoesophageal fistula or esophageal atresia, which could present with cough and vomiting due to aspiration.
  • Other rare infections like pertussis-like illnesses caused by other bacteria (e.g., Chlamydophila pneumoniae, Mycoplasma pneumoniae) might also be considered, though they are less likely in a non-immunized child with a classic pertussis presentation.