Differential Diagnosis for a 3-year-old Child with Eye Infection and Cough

Single Most Likely Diagnosis

• Viral Conjunctivitis with a concurrent Upper Respiratory Tract Infection (URTI): This is the most likely diagnosis given the common occurrence of viral conjunctivitis and URTIs in children. The symptoms of eye infection (redness, discharge) and cough are consistent with a viral etiology.

Other Likely Diagnoses

• Bacterial Conjunctivitis with a concurrent URTI: Bacterial conjunctivitis can present similarly to viral conjunctivitis but may have a thicker, more purulent discharge. The cough could still be part of a URTI.
• Allergic Conjunctivitis with a concurrent URTI: Allergic reactions can cause eye symptoms similar to an infection, and if the child has allergies, this could be a consideration, especially if the cough is related to allergic rhinitis.
• Influenza or other Viral Respiratory Infections: Influenza and other viral respiratory infections can cause both eye and respiratory symptoms, including cough.

Do Not Miss Diagnoses

• Pertussis (Whooping Cough): Although less common due to vaccination, pertussis can cause a severe cough and, in some cases, may be associated with conjunctivitis. It's crucial to consider this diagnosis due to its potential severity and the need for public health measures.
• Tuberculosis: TB can cause chronic cough and eye infections, among other symptoms. While less common, it's a critical diagnosis not to miss due to its implications for the child and public health.
• Lymphogranuloma Venereum (LGV): This is a sexually transmitted infection that can cause conjunctivitis and other systemic symptoms, including cough. In a child, it would raise concerns about sexual abuse.

Rare Diagnoses

• Cystic Fibrosis: This genetic disorder can lead to recurrent respiratory infections and, in some cases, eye infections due to malnutrition or other complications. It's a rare condition but one that significantly impacts the child's quality of life and management.
• Immunodeficiency Disorders: Conditions like HIV/AIDS or primary immunodeficiencies can predispose children to a variety of infections, including those of the eyes and respiratory system. These are rare but critical diagnoses due to their impact on the child's health and management.