Differential Diagnosis for a 6-year-old with Cough
Single Most Likely Diagnosis
- Viral upper respiratory tract infection (URTI): The initial symptoms of diarrhea and runny nose that improved, followed by a persistent cough, are consistent with a common cold or viral URTI, which is prevalent in children and often presents with these symptoms.
Other Likely Diagnoses
- Asthma: A cough that persists, especially if it worsens at night or with activity, could be an initial presentation of asthma, especially if there's a family history or other suggestive symptoms like wheezing.
- Pertussis (Whooping Cough): Although less common due to vaccination, pertussis can cause a persistent cough, often with a characteristic whoop sound, and is more severe in younger children.
- Allergic rhinitis: If the cough is dry and accompanied by other symptoms like sneezing, itchy eyes, or a runny nose, allergic rhinitis could be a consideration, especially if there are known allergies.
Do Not Miss Diagnoses
- Pneumonia: While less likely given the initial improvement of other symptoms, pneumonia can present with cough and should be considered, especially if the child has a fever, difficulty breathing, or chest pain.
- Foreign body aspiration: In children, aspiration of a foreign body can cause sudden onset of cough and respiratory distress, and it's crucial to consider this in the differential due to its urgency.
- Tuberculosis (TB): Although rare in many areas, TB can cause a chronic cough and is a critical diagnosis not to miss due to its public health implications and the need for specific treatment.
Rare Diagnoses
- Cystic fibrosis: A persistent cough, especially if accompanied by other symptoms like poor growth or recurrent infections, could suggest cystic fibrosis, a genetic disorder that affects the lungs and digestive system.
- Bronchiectasis: This condition, characterized by damaged airways, can cause a chronic cough and is often associated with underlying conditions or recurrent infections.
- Immunodeficiency: Certain immunodeficiencies can predispose children to recurrent or severe infections, including those causing cough, and should be considered in the context of recurrent or unusual infections.