Conditions · Pediatrics and neonatology
Roseola infantum (exanthem subitum) !
A common childhood virus infection: a few days of high fever, then a pink rash appears just as the fever goes away.
Updated 2026-11-01
Structures involved
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Microorganisms that cause it
What it is
A viral exanthem of infants and toddlers, usually caused by human herpesvirus 6 (HHV-6) and less often HHV-7, with 3–5 days of high fever followed, as the fever breaks, by a pink maculopapular rash on the trunk.
Who gets it
Most children are infected with HHV-6 by age 2; peak age is 6 months to 2 years. It occurs year-round worldwide, including Colombia, and spreads through saliva from asymptomatic adults and older children.
Causes
- Human herpesvirus 6 (mainly HHV-6B)
- Human herpesvirus 7 in some cases
- Spread by saliva and respiratory secretions
Risk factors
- Age 6 months to 3 years, after maternal antibodies wane
- Close contact with siblings or adults who shed the virus
- Childcare attendance
Pathophysiology
HHV-6 infects CD4 T lymphocytes and causes viremia with high fever. The rash appears as the immune response clears the virus. Like other herpesviruses it stays latent for life and can reactivate in immunosuppressed people.
Symptoms and signs
- Sudden high fever, often above 39.5 °C, for 3–5 days in a child who looks relatively well
- Pink, small maculopapular rash starting on the trunk and spreading to the neck and face as fever ends
- Irritability and decreased appetite
- Mild cervical or occipital lymphadenopathy
- Red papules on the soft palate and uvula (Nagayama spots) and eyelid swelling
Diagnosis
- Clinical
- Clinical, based on the classic sequence: high fever with no focus, then a rash as the fever falls.
- Tests
- Usually none. During the fever, tests may be done to exclude bacterial infection (urinalysis, blood count); HHV-6 serology or PCR only in atypical or immunosuppressed cases.
- Imaging
- Not needed.
Differential diagnosis
- Measles (rash with fever, cough and conjunctivitis)
- Rubella
- Erythema infectiosum (fifth disease)
- Scarlet fever
- Drug rash after antibiotics given during the fever
- Urinary tract infection or serious bacterial infection in the febrile phase
Goal of treatment
Keep the child comfortable and hydrated, recognize febrile seizures and exclude serious bacterial infection during the fever.
Treatment
- Conservative
- Fluids, rest and light clothing; the rash is not itchy and needs no treatment.
- Medical
- Antipyretics (acetaminophen or ibuprofen) for comfort; they do not prevent febrile seizures.
- Acute
- A febrile seizure is managed with airway protection and positioning; benzodiazepines are used if it is prolonged.
- Follow-up
- Observation for dehydration and neurological signs; antivirals (ganciclovir, foscarnet) are reserved for immunosuppressed patients with severe disease.
Complications
- Febrile seizures, the most frequent complication
- Encephalitis (rare)
- Hepatitis (rare)
- Reactivation after transplantation in immunosuppressed patients
Prognosis
Excellent in healthy children; it resolves in about a week without sequelae and gives lasting immunity.
Test yourself
Think of the answer, then tap the question to see it.
Which virus causes most cases of roseola infantum?
Human herpesvirus 6 (HHV-6B); HHV-7 causes some cases.
What is the classic sequence of roseola?
Three to five days of high fever, then a pink trunk rash as the fever breaks.
What is the most common complication of roseola?
Febrile seizures during the high fever.
At what age does roseola usually occur?
Between 6 months and 2 years.
Related conditions
- Febrile seizures
- Measles
- Rubella and congenital rubella syndrome
- Erythema infectiosum (fifth disease, parvovirus B19)
- Scarlet fever
- Hand, foot and mouth disease
- Kawasaki disease
- Varicella (chickenpox)
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Roseola (MedlinePlus Medical Encyclopedia (U.S. National Library of Medicine), 2025).
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