It is estimated that only about 10% of children who become infected with EBV develop the illness, likewise, probably because of immunity from prior infection, adults typically do not develop the illness. Signs of mono: swelling around the eyes, rash, weight loss, drowsiness, muscle aches or stiffness.
Less frequently occurring symptoms and signs include: mild jaundice (a yellowish tint to skin), neck stiffness, sensitivity to light/FONT, cough, shortness of breath, chest pain ,rapid and/or irregular heart rate, nosebleeds, hives.
Most cases of infectious mononucleosis occur in the 15-24 age group.
About 5% of patients have a splotchy red rash over the body, which has a similar appearance to the rash of measles. Early in the course of disease (over the first few days of illness), a temporary swelling (edema) of both upper eyelids may appear.