A 3-year child presents with a 3-day history of malaise, fever 41.1°C, cough, coryza, and conjunctivitis, then develops erythematous maculopapular rash on the face. He is noted to have white pinpoint lesions on a bright red buccal mucosa in the area opposite his lower molars.

A 14-month-old infant presents with a 4-day history of high fever without any localising signs. At the peak of fever, the baby suffers a short convulsive fit and is admitted for observation. The next day, the fever subsides, but a maculopapular rash develops over the trunk and abdomen.

A 14-year-old boy presenting with a 3-week history of fever between 38.3°C and 38.9°C, lethargy. Physical examination reveals marked cervical and inguinal adenopathy, enlarged tonsils with exudates, palpable spleen 2 cm below the left costal margin.

A previously healthy 8-year-old boy has a 3-week history of low grade fever of unknown source, fatigue, weight loss, myalgia, and headache. On repeated examinations during this time, he is found to have developed a heart murmur, petechiae, and mild splenomegaly.

A 14-year-old boy presenting with a 3-week history of fever between 38.3°C and 38.9°C, lethargy. Physical examination reveals marked cervical and inguinal adenopathy, enlarged tonsils with exudates, palpable spleen 2 cm below the left costal margin. WBC differential has 50% lymphocytes (10% atypical).

A 12-year-old girl awakens with a mild sore throat, low-grade fever, and a diffuse maculopapular rash. During the next 24h, she develops tender swelling of her wrists and redness of her eyes. In addition, her physician notes mild tenderness and marked swelling of her posterior cervical and occipital lymph nodes. Four days after the onset of her illness, the rash had vanished.