Differential Diagnosis for 8-Month-Old with Pink Eye

• Single Most Likely Diagnosis
  • Viral conjunctivitis: This is the most common cause of pink eye in infants, often presenting with redness, discharge, and tearing. It is highly contagious and usually self-limiting.
• Other Likely Diagnoses
  • Bacterial conjunctivitis: Caused by bacteria such as Staphylococcus aureus, Haemophilus influenzae, or Streptococcus pneumoniae, it presents similarly to viral conjunctivitis but may have a thicker, more purulent discharge.
  • Allergic conjunctivitis: Although less common in infants, allergic reactions to environmental allergens can cause conjunctival inflammation, itching, and tearing.
• Do Not Miss Diagnoses
  • Gonococcal conjunctivitis: A serious infection caused by Neisseria gonorrhoeae, which can lead to corneal perforation and vision loss if not promptly treated. It is particularly concerning in newborns but can occur in infants if exposed.
  • Chlamydial conjunctivitis: Caused by Chlamydia trachomatis, this infection can lead to long-term consequences, including blindness, if not adequately treated.
  • Herpes simplex virus (HSV) keratoconjunctivitis: HSV can cause a severe, vision-threatening infection that requires prompt antiviral treatment.
• Rare Diagnoses
  • Kawasaki disease: Although primarily known for its systemic symptoms, Kawasaki disease can present with bilateral nonexudative conjunctivitis.
  • Sjögren's syndrome: An autoimmune disorder that can cause conjunctivitis, though it is exceedingly rare in infants.
  • Leukemic infiltration: In rare cases, conjunctival infiltration by leukemic cells can cause conjunctivitis in infants with leukemia.