Roseola infantum

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

References:^[1][2]

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

References:^[1][3]

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
• Other possible symptoms:
  • Mild upper and lower respiratory symptoms (pharyngitis, cough, etc.)
  • Vomiting and/or diarrhea
  • Conjunctivitis and edema of the eyelid

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

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).

References:^{[1][4][5][6][7][8]}

• Usually a clinical diagnosis
• Laboratory tests
  • Antibody testing: HHV-6 IgM detection is possible.
  • Viral DNA testing: pathogen DNA detection via PCR (possible detection using blood, urine, cerebrospinal fluid, or saliva samples)

References:^[7]

• Other infectious rashes in childhood
• Drug reactions
• Meningitis

References:^[7]

The differential diagnoses listed here are not exhaustive.

• Symptomatic treatment; (e.g., fluids and possibly acetaminophen to reduce fever)

References:^[7]

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

References:^[5]

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)