Roseola Infantum (Exanthem Subitum)

Key Features

Essentials of Diagnosis

• High fever in a child aged 6–36 months

• Minimal toxicity

• Rose-pink maculopapular rash appears when fever subsides

General Considerations

• Caused by HHV-6 or HHV-7

• Occurs predominantly in children aged 6 months to 3 years, with 90% of cases occurring before the second year

• HHV-7 infection tends to occur somewhat later in childhood

Clinical Findings

Symptoms and Signs

• Fever

  • Abrupt onset, often reaching > 39.5°C

  • Lasts up to 8 days (mean, 4 days) in an otherwise mildly ill child

  • Ceases abruptly, and a characteristic rash may appear

• Rash

  • Incidence is 20–30%

  • Begins on the trunk and spreads to the face, neck, and extremities

  • May occur without fever

  • Characteristics

    • Rose-pink macules or maculopapules, 2–3 mm in diameter

    • Nonpruritic

    • Tend to coalesce and disappear in 1–2 days without pigmentation or desquamation

• Pharynx, tonsils, and tympanic membranes may be injected

• Conjunctivitis and pharyngeal exudate are notably absent

• Diarrhea and vomiting occur in one-third of patients

• Adenopathy of the head and neck often occurs

• The anterior fontanelle is bulging in one-quarter of HHV-6–infected infants

Differential Diagnosis

• Measles

• Rubella

• Adenoviruses

• Enteroviruses

• Drug reactions

• Scarlet fever

• Bacterial meningitis

Diagnosis

• Leukopenia and lymphocytopenia are present early

• Hepatitis occurs in some patients

Treatment

• Acetaminophen and sponge baths used for fever control, especially in children with history of febrile seizures

• Antiviral agents are used for systemic infection in immunocompromised children

Outcome

Complications

• Febrile seizures occur in up to 10% of patients (even higher percentages in those with HHV-7 infections)

• Meningoencephalitis caused by HHV-6 directly infecting the central nervous system

• Multiorgan disease may occur in immunocompromised patients

  • Pneumonia

  • Hepatitis

  • Bone marrow suppression

  • Encephalitis

Reference