• 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 (e.g., saliva)
  • Incubation period: 5–15 days


Clinical features

Febrile phase

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 rush)
    • Originates on the trunk; ; sometimes spreads to the face and extremities

The names of the disease reflect its two phases: Three-day fever refers to 3 days of high fever; exanthem subitum (from Latin: "subitus" = sudden) describes a "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, and reactivation of latent virus or reinfection may occur later in life (especially if individuals become immunocompromised)