The patient is usually an adolescent or a young adult between the ages of 15 and 25 complaining of several days of fever, malaise, myalgias, and anorexia, culminating in a severe sore throat. The physical examination is remarkable for lymphadenopathy, typically bilateral posterior cervical chains, and enlarged tonsils, at times meeting in the midline and covered with an exudate, which can be white, green, yellow, or necrotic appearing. There may also be palatal petechiae and swelling, periorbital edema, splenomegaly (often not evident clinically), hepatomegaly, and, less commonly, a diffuse maculopapular rash or jaundice (more common in patients who are >40 years of age).