External Eye Involvement in Epstein Barr Virus Infectious Mononucleosis Periorbital edema is a rare characteristic of EBV infectious mononucleosis. It presents in the first few days of illness only. However, this characteristic suggests some differential diagnoses. • Bilateral periorbital edema with no generalized edema suggests – Kawaski disease, trichninosis, bilateral periorbital cellulitis and allergic reactions • Unilateral periorbital edema suggests – Retro-orbital eye tumor, insect sting, Chagas disease, thyrotoxicosis, unilateral conjunctivitis