Epidemiology

• Peak incidence: 6 months to 2 years

Etiology

• Pathogen
  • HHV-6 (and in rare cases HHV-7)
  • Humans are the sole hosts.
• Route of transmission: droplet infection (e.g., saliva)

Pathophysiology

Clinical features

Febrile phase

• Duration: 3–5 days
• Fever
  • Abrupt onset of high fever, in some cases > 40ºC (104ºF)
  • Febrile seizures are a potential complication of roseola (see “Complications” below).
• Cervical, postauricular, and/or occipital lymphadenopathy
• Inflamed tympanic membranes
• Nagayama spots: papular enanthem on the uvula and soft palate

Exanthem phase

• Duration: 1–3 days
• Characteristic presentation: subsequent sudden decrease in temperature and development of a patchy, maculopapular exanthem
  • Rose-pink in color; blanches upon pressure
  • Nonpruritic (in contrast to the drug allergy rash)
  • Originates on the trunk; sometimes spreads to the face and extremities

Diagnostics

Treatment