A number of conditions may present with a syndrome very much like infectious mononucleosis. Diagnosis often depends on a careful history and physical examination followed by laboratory tests.
Patient features:
(1) prolonged fever
(2) lymphadenopathy
(3) fatigue
(4) pharyngitis
(5) skin rash
(6) atypical lymphocytosis
(7) elevated serum transaminase levels
(8) negative screening test for infectious mononucleosis (heterophile antibody test, Monospot)
Diagnosis
Features
heterophile negative infectious mononucleosis
more common in children; antibodies to EBV antigens positive
cytomegalovirus (CMV)
sexual contact, blood transfusion
rubella (German measles)
lack of MMR vaccination; no history of childhood exposure
primary HIV
unprotected sexual contact, blood transfusion, injection drug use
toxoplasmosis
animal contact, raw meat
herpesvirus 6 (roseola)
infant or young child
cat-scratch fever
animal contact, lymphadenopathy
leukemia, malignant lymphoma
atypical lymphocytosis, lymphadenopathy
cancer
lymphadenopathy, fatigue
hypersensitivity drug reaction
diphenylhydantoin, other
mumps
lack of MMR vaccination; no history of childhood exposure; parotitis and/or orchitis
acute viral hepatitis
jaundice, positive serologic tests
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