What is the most common etiology of Parinaud's Oculoglandular Syndrome?

• A. Cat scratch fever
• B. Tularemia
• C. Lyme disease
• D. Syphilis

Answer: (A)

Parinaud's oculoglandular syndrome presents as unilateral granulomatous conjunctivitis with ipsilateral preauricular lymphadenopathy. The classic cause is cat scratch disease from Bartonella henselae, typically transmitted to the eye after a cat scratch or bite. The conjunctival infection triggers a localized granulomatous response, and the regional lymphatics drain to the preauricular nodes, producing the characteristic lymphadenopathy on the same side. Among infectious etiologies, Bartonella henselae is the most commonly identified agent in this syndrome, making cat scratch fever the best explanation. Other agents like Francisella tularensis (tularemia), Borrelia burgdorferi (Lyme), or Treponema pallidum (syphilis) can cause ocular signs but are far less commonly associated with this specific presentation.