TABLE 1.

Prevalence of signs, symptoms, and laboratory abnormalities in infectious mononucleosisa , b

FindingPrevalence (%)Comment
Signs
    Pharyngitis100Occasionally seen without sore throat
    Cervical lymphadenopathy95Especially posterior cervical and postauricular
    Fever50Often masked by antipyretics
    Hepatomegaly25
    Splenomegaly33
    Eyelid edema10Unusual in other acute illnesses
    Rash5Virtually all patients given penicillin derivatives develop a rash
Symptoms
    Sore throat95Many patients describe this as the “worst” they have ever had
    Fatigue90Usually the last symptom to resolve
    Headache75Common but underappreciated
    Fever70
    Body aches50Patients describe this as “like the flu”
    Decreased appetite50
    Abdominal discomfort40Due to mesenteric adenitis or hepatosplenomegaly
Laboratory abnormalities
    Alanine aminotransferase elevation80Five to 10% of patients are jaundiced
    Leukocystosis40Usually due to increase in CD8 cytotoxic lymphocytes
    Thrombocytopenia25Thought to be autoimmune
    Anemia10Thought to be autoimmune
  • a Based on a compilation of published series (54, 67, 84, 130, 167) and 116 subjects followed in natural history and treatment trials at the University of Minnesota (14-16).

  • b The median duration of illness is 16 days, and the mean duration is 19 days.