DESCRIPTION

Roseola infantum (also called exanthem subitum) is a common illness in preschool-aged children with a classic presentation of fever lasting 3 to 7 days followed by rapid defervescence and appearance of erythematous, maculopapular rash.

EPIDEMIOLOGY

• Roseola affects children from 3 months to 4 years of age. The peak age is 6 to 12 months.
• 90% of cases occur in the first 2 years of life.
• No gender predilection
• Roseola can occur throughout the year without seasonal patterns.

ETIOLOGY

• The major causes of roseola are human herpesvirus (HHV)-6 and HHV-7.
  • HHV-6 was first associated with roseola infantum in 1988.
  • HHV-6 and HHV-7 account for around 20% of unexplained febrile illness in emergency department visits by febrile infants 6 months to 2 years of age.
  • Almost all children will acquire a primary infection and be seropositive for HHV-6 by the age of 4 years.
  • ~30% of children infected with HHV-6 will present with the classic manifestations of roseola.
• Roseola-like illnesses have been associated with a number of different viruses, including:
  • Enterovirus (coxsackievirus A and B, echoviruses)
  • Adenoviruses (types 1, 2, 3)
  • Parainfluenza virus
  • Measles vaccine virus

GENERAL PREVENTION

• The virus that causes roseola infantum is usually transmitted via respiratory secretions or fecal–oral spread.
• Good hand hygiene is recommended.
• Outbreaks in hospitals have been reported, and standard infection control precautions are recommended.

PATHOPHYSIOLOGY

• Incubation period is 5 to 15 days depending on etiology. HHV-6 has a typical incubation period of 9 to 10 days, whereas in HHV-7, it is unknown.
• The typical pattern of rash that appears as the fever disappears may represent virus neutralization in the skin.