• Clinical science

Roseola infantum (Exanthem subitum…)


Roseola infantum (exanthem subitum, three-day fever) is a viral exanthematous infection caused by the human herpes virus 6 (HHV-6; in rare cases, HHV-7) that mainly affects infants and toddlers. Infection is characterized by high fever, which ends abruptly after three to five days, followed by the sudden appearance of a maculopapular rash. The rash generally appears mainly on the trunk, but sometimes spreads to the face and extremities, and fades within two days. Roseola infantum is a self-limiting condition that is only treated symptomatically. Febrile seizures are a possible complication of infection; however, most patients recover from these seizures without any adverse outcome.


  • Most frequent in infants and young children
  • Peak incidence: 6 months to 2 years


Epidemiological data refers to the US, unless otherwise specified.


  • Pathogen
    • HHV-6; (and in rare cases HHV-7)
    • Humans are the sole hosts.
  • Route of transmission: droplet infection
  • Incubation period: 5–15 days


Clinical features

Febrile phase

  • Duration: 3–5 days
  • Fever
    • Abrupt onset of high fever, in some cases > 40ºC (104ºF)
    • Frequent cause of emergency room visits for febrile illness
  • Cervical, postauricular, and/or occipital lymphadenopathy (in ∼ 98% of cases)
  • Inflamed tympanic membranes (in ∼ 93% of cases)
  • Nagayama spots: papular enanthem on the uvula and soft palate (in ∼ 87% of cases)
  • Other possible symptoms:

Exanthem phase

  • Duration: 2–3 days
  • Characteristic presentation: subsequent sudden decrease in temperature and development of a patchy, maculopapular exanthem
    • Rose-pink in color; blanches upon pressure
    • Nonpruritic (DDx: drug allergy!)
    • Originates on the trunk; → sometimes spreads to the face and extremities
    • Duration: 1–2 days

The names of the disease reflect its two phases: three-day fever3 days of high fever; exanthem subitum (from Greek: "subitus-" = sudden) → "sudden exanthem" (upon fever cessation)!




Differential diagnoses


The differential diagnoses listed here are not exhaustive.




  • Febrile seizures (in up to 15% of cases), usually without sequelae
  • Meningoencephalitis (very rare)


We list the most important complications. The selection is not exhaustive.


  • Very good prognosis; self-limiting disease
  • The virus persists lifelong in its host → reactivation of latent virus or reinfection may occur later in life (especially if individuals become immunocompromised)